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SLEEP ACTIVITIES
By: Mohibullah Fazli Kakar
Trainee of Neurophysiology
French Medical Institute for Children
Sleep stages
•Drowsiness Alpha dropout (earliest sign)
• Increased beta activity over the frontocentral regions
• Diff use rhythmic theta activity with anterior
predominance
• Slow eye movement
• Mu rhythm, wicket wave, and 14 and 6 Hz positive spikes
can be seen.
• Deep drowsiness is marked by the vertex waves and
POSTS that persist during light sleep and deep sleep
• Hypnagogic hypersynchrony in 3 months to 8 years.
Sleep stages
•Stage 2 sleep
• Symmetric, synchronous theta rhythms with posterior
predominance, 12–15/sec spindles, vertex sharp waves,
K-complexes, and POSTS.
• Sleep spindles in the 12–15/sec range are hallmark of
sleep onset.
Sleep stages
•Stage 3 sleep Delta frequencies in the 0.75–
3/sec range are prominent over the anterior
regions.
• Sleep spindle in the 10–12/sec and even in the
12– 14/sec ranges are still present but gradually
become less prominent.
• Rhythmic activity of 5–9/sec is common.
• Rhythmic and symmetrical delta activity is noted
between 20% and 50% of the recording
Sleep stages
• Stage 4 sleep
• Over 50% of the recording is delta rhythm.
• Spindles are rare.
• Arousal at this stage can be correlated with sleep
disorders (somnambulism, nocturnal terror, or enuresis),
and can cause confusion.
• Occasionally, spikes in temporal lobe epilepsy will only
appear in stage 3 and 4 sleep.
Sleep stages
•REM sleep Low-voltage activity, polyrhythmic
waves, and slower alpha waves.
• Short bursts of “saw-tooth waves” over the frontal
or vertex leads and quick lateral eye movements.
• Appearance of REM sleep in routine EEG is
seen in narcolepsy and in patients who are
withdrawn from CNS depressants such as alcohol
or phenobarbital
K-Complex
• Contain 3 components including sharp, slow, and fast.
• Seen in stage 2 sleep and arousal.
• Largest in older children and adolescence. With
advanced age, the K-complexes show the decline in
voltage with tiny superimposed spindle-like waves.
• First appears at 4 months of age.
• They have high amplitude but their rise is not as abrupt
and the configuration is not as sharp as seen in older
children.
Sleep spindles
• Arise from synchronized activity in neuronal networks
linking the thalamus and the cortex.
• Spindles result from rhythmic spike bursts in inhibitory
(GABAergic) thalamic reticular neurons that induce
rhythmic rebound bursting in cortical neurons resulting in
effective deafferentiation of the cerebral cortex.
• Cortical neurons show enhanced synaptic plasticity that
might have a role in memory and learning processes.
• First seen at 1.5–2 months with a frequency of 14/sec.
Sleep spindles
• Throughout infancy, they are maximal over the central and
parietal areas with shifting asymmetry.
• They usually are electronegative with rounded positive
component that is a typical hallmark of sleep spindles in
infancy.
• These surface-negative spindles with wicket or comb-like
shape can be erroneously interpreted as 14/sec positive
spikes
• Between the ages of 3 and 6 months, sleep spindles
appear to be biphasic and as prolonged runs, up to 10–
15 sec. The prolonged run of spindles is a very useful
developmental marker and is rarely seen beyond this age
range
Sleep spindles
• Subharmonic or harmonic of sleep spindles with a
frequency approximately half or double that of sleep
spindles and notched appearance can be seen.
• In the second half of the first year of life, the spindles
appear to be monophasic and are often asynchronous
between the two sides.
• The frequency of spindles also changes, with 12/sec
components becoming more prominent.
• Asynchronous spindles may occasionally continue from 1
to 2 year of age but rarely are seen after the age of 2
years when interhemispheric synchrony of the spindles
appears.
Mitten patterns
• Consist of a sharp-contoured waveform on the slope of a
slow wave of the same polarity that resembles a mitten,
with a thumb of mitten formed by the last wave of a
spindle and the hand portion by the slower wave
component.
• Maximal at the frontocentral vertex with spread into
parasagittal regions.
• The location is different from K-complexes in that it is
centered anterior to the central vertex where K-complexes
are maximal.
• Variant of a vertex wave or K-complex and should not be
mistaken for a spike-and-wave discharge.
• It is best seen in referential montage in stage 3 sleep.
Hypnagogic hypersynchrony
• Seen in early drowsiness and arousal from deeper sleep.
• Characterized by bilateral synchronous, high voltage,
rhythmic 3–5 Hz activity.
• The frequency of hypnagogic hypersynchrony is 3–4 Hz
at the age of 2–3 months and increases to 4–5 Hz in older
children.
• Asymmetric hypnagogic hypersynchrony with shifting
predominance can be seen and is not considered
abnormal.
• At 2–3 months, first appears.
• At 9 months, more prominent and continuous.
• Between 4 months and 2 years, seen in almost all infants
Hypnagogic hypersynchrony
• Few infants do not show this pattern but show occipital or
widespread rhythmical and synchronous
• 4–5 Hz waves of low to medium amplitude.
• At 4 years, shorter in duration and more paroxysmal.
• At 9–11 years, it becomes rare (10%).
• Although the presence of hypnagogic hypersynchrony
• at age 12 years is considered abnormal by some
• authors, it may be seen in normal children up to the age of 12–
13 years.
• Occasionally, small sharp or spiky discharges may be
interspersed between the theta waves.
• These discharges should not be interpreted as epileptiform
activity unless they are definitely distinct from background
activity and not only occur during drowsiness or at the onset of
sleep but persist into deeper stages of sleep.
Hypnic myoclonia (hypnagogic jerks)
• This wake-to-sleep transition event is characterized
by a sudden, single, brief muscular contraction of the
legs and occasionally the arms, head, and postural
muscles.
• Sensory hallucinations (hypnagogic hallucinations)
often occur before the hypnic myoclonia.
• Hypnic myoclonia occurs in 60–79% of normal
population.
• Although it may occur at any age, 90% of patients
stop these movements by age of 4 years.
• They are more common in boys than girls by 4:1.
Midline theta rhythm
• Rare nonspecific finding of no clinical significance.
• Rhythmic train of 5–7 Hz theta activity occurring in the
central vertex but may also be seen in the frontal vertex.
• Morphology includes sinusoidal, aciform, spiky, or mu-like
appearance.
• Seen during wakefulness and drowsiness.
• Variable reactivity to eye opening, alerting, and limb
movement.
• The rhythm usually lasts from 3 to 20 sec and does not
evolve.
Frontal arousal rhythm (FAR)
• Rare nonspecific EEG pattern of no clinical significance.
• Frontal regions (F3 and F4 electrodes with minimal
spread to nearby scalp areas) during arousal from sleep
in children.
• Characterized by 30–150 μV, predominantly monophasic
negative waves, occurring in bursts or runs lasting up to
13 sec (usually 1–5 sec) with a characteristic notching of
the ascending or descending phase of each wave that
may represent harmonics of the waveforms.
Frontal arousal rhythm (FAR)
• The waxing and waning of the amplitude often leads
• to a spindle-like morphology.
• 70% of patients having epileptic seizures; a reported
case in which FAR representing ictal electrographic
seizure activity.
Rhythmic temporal theta bursts of
drowsiness, rhythmic midtemporal
discharges (RMTD), psychomotor variant
• Benign variant of no clinical signifi cance.
• Seen in 0.5–2.0% of normal adult population and less
common in adolescence. No prevalence in childhood.
• Bursts or runs of rhythmic, 5–7 Hz or 4–7 Hz (typically
• 5–5.5 Hz), theta activity with fl at-topped, sharply
contoured, often notched appearance in the temporal
regions.
• Maximally expressed in the mid- or anterior temporal
• electrodes.
• Monomorphic pattern with amplitude of 50–200 μV.
• Duration: commonly 5–10 sec; vary from 1 to >60 sec
with gradual onset and off set.
Rhythmic temporal theta bursts of
drowsiness, rhythmic midtemporal
discharges (RMTD), psychomotor variant
• The sharper component of the wave usually has a negative
polarity in the anterior temporal region.
• Unilaterally with shifting from side to side greater than
bisynchronous.
• Differentiated from ictal epileptiform activity by Monomorphic
and monorhythmic (no evolution into other frequencies
although amplitude can vary)
• No alteration of background activity Occurrence in relaxed
wakefulness and drowsiness (most common) and
disappearancein deeper levels of sleep.
• Although it has no clinical significance, it was considered by
some authors to be a pathologic finding in selected cases.
Fourteen and six per second positive
spike discharge
• Benign variant of no clinical significance.
• Bursts of arch-shaped waves at 13–17 Hz and/or 5–
7 Hz, most commonly at 14 and/or 6 Hz. The 14 Hz
• component is more commonly seen than 6 Hz.
• Maximal over the posterior temporal and adjacent
areas of one or both sides of the head.
• Amplitude <75 μV.
• Appearance in deep drowsiness and very light sleep
and disappearance in deeper levels of sleep.
• Electropositive of sharp component and
electronegative of smooth component.
Fourteen and six per second positive
spike discharge
• Widespread fi eld lasting for 0.5–1 sec.
• Occurs in children after age 3 to young adult but
more common between 12 and 20 years with a peak
at age 13–14 years.
• Best seen in contralateral ear reference montage.
• Appearance in diff use encephalopathy EEG pattern
in a wide variety of encephalopathies of childhood
suggesting that they are epiphenomena or a resilient
normal.
• Frequency is more variable and can be elicited by
alerting stimuli.
Small sharp spike (SSS) or benign
epileptiform transients of sleep (BETS)
• Benign variant of no clinical signifi cance.
• 20–25% of a normal adult population.
• Appearance in deep drowsiness and very light sleep and
disappearance in deeper stages of sleep.
• Usually low voltage, short duration, single monophasic,
or biphasic spike with an abrupt ascending limb and a
steep descending limb.
Six-hertz spike-wave bursts (phantom
spike-wave)
• Benign variant of no clinical signifi cance.
• 2.5% of both adolescents and young adults; 0.5–1%
overall.
• Appearance in relaxed wakefulness, drowsiness, and
light sleep and disappearance in deeper levels of sleep.
• Bursts of 1–2 sec duration diff use, low voltage (<40 μV),
short duration (<30 msec), 5–7 Hz, spike-andwave
• discharges, commonly bifrontal or occipital.
• 25% of phantom spike and wave have repetitive rate of 4
Hz.
Six-hertz spike-wave bursts (phantom
spike-wave)
• At times, spikes are difficult to see.
• Six-hertz spikes with minimal or no associated waves
may represent a transitional pattern between
• 6-Hz spike-wave bursts and 14 and 6-Hz positive
bursts.
• Waking, high-amplitude, anterior, male (WHAM) vs
female, occipital, low-amplitude, drowsy (FOLD).
• WHAM is more likely to be associated with seizures
if the repetitive rate is <5 Hz or amplitude of spike
greater than slow wave.
Wicket waves
• One of the most common over-read EEG patterns seen almost
exclusively in adults, most commonly >30 years of age and,
usually, older than 50 years.
• Benign variant pattern and is not associated with epilepsy.
• Rare waveform (0.9%).
• It occurs in clusters or trains, but also as single sharp
transients, of 6- to 11-Hz negative sharp aciform waves with
amplitude of 60–200 μV.
• Anterior or midtemporal regions.
• Seen during relaxed wakefulness but facilitated by drowsiness
and may occur in light sleep.
• Recently wicket waves have also been reported to occur
during REM sleep.
Wicket waves
• Unilaterally with a shifting asymmetry between the
• two hemispheres.
• During the wakefulness, wicket waves are often masked
by background EEG activity.
• Cardinal feature is a changing mode of occurrence
through any single recording, from intermittent trains of
more or less sustained, aciform, discharges resembling
mu rhythm, to sporadic single spikes.
• Amplitude may be high, but the transient arises out
• of an ongoing rhythm and does not stand out
Wicket waves
• When occurring singly, wicket waves can be mistaken for
anterior or middle temporal spikes.
• Isolated wicket wave can be differentiated from epileptiform
discharge by the following criteria:
• No slow wave component following the wicket wave
• Occurring in trains or in isolation and do not disrupt the
background
• Similar morphology to the waveforms in the train when
occurring as a single spike
• More commonly seen in patients with cerebrovascular
disease.
• The age (younger than 30 years) and abnormal background
activity are strongly against the diagnosis of wicket waves and
supportive of epileptiform activities
• In older children and adults, early drowsiness is
associated with
• (1) alpha dropout (earliest sign)
• (2) increased beta activity over the fronto-central regions
• (3) diff use rhythmic theta activity with anterior
predominance;
• and (4) slow eye movement.
• Mu rhythm, wicket wave and 14- and 6 Hz positive spikes
can be seen during drowsiness.
Drowsiness; Older Children and Adults
• Drowsiness must be differentiated from increased
alertness after eye opening or caused by emotional stress
that can cause alpha blocking.
• In such cases the slow frequency component is absent
and beta frequency predominates.
• Deep drowsiness is marked by the appearance of vertex
waves and POSTS that persist during light sleep and
deep sleep
Drowsiness; Older Children and Adults
Drowsiness; Older Children and Adults
• In older children and adults, early drowsiness is associated with
• (1) alpha dropout (earliest sign);
• (2) increased beta activity over the fronto-central regions (double
arrows)
• (3) diff use rhythmic theta activity with anterior predominance (open
arrow)
• and (4) slow eye movement (doublehead arrow).
• Mu rhythm, wicket wave and 14- and 6 Hz positive spikes (*) can be
seen during drowsiness.
• Drowsiness must be differentiated from increased alertness after eye
opening or caused by emotional stress that can cause alpha blocking.
• In such case slow frequency component is absent and beta frequency
predominates.
• Deep drowsiness is marked by the appearance of vertex waves and
POSTS that persist during light sleep and deep sleep
Drowsiness; 14-and-6 Hertz Positive Bursts
Drowsiness; 14-and-6 Hertz Positive Bursts
• Stage 2 sleep shows symmetric, synchronous theta
rhythms with posterior predominance, 12–15/sec
spindles, vertex sharp waves, K-complex and POSTS.
• The appearance of sleep spindles in the 12–15/sec range
is a hallmark of sleep onset
Stage 2 (Light Sleep
Stage 2 (Light Sleep
• Subdural recording showing the sleep spindles in the
parietal lobe during sleep.
• A harmonic of the sleep spindles is more frequently seen
in intracranial EEG.
• In addition, the sleep spindles usually appear sharper in
morphology as the scalp and skull act as a high-frequency
filter and pass lower frequencies more efficiently than
higher frequencies.
• Disappearance during wakefulness helps to differentiate
the sleep spindles from low-voltage fast activity.
• All normal EEG rhythms seen in the scalp EEG can be
seen in the intracranial EEG
Sleep Spindles During Subdural EEG Recording
Sleep Spindles During Subdural EEG Recording
• Delta frequencies in the 0.75–3/sec range are prominent
over the anterior regions.
• Sleep spindles in the 10–12/sec and even in the 12–
14/sec ranges are still present but gradually become less
prominent.
• Rhythmic activity of 5–9/sec is common.
• Rhythmic and symmetrical delta activity occurs during
20% to 50% of the recording
Stage 3 (Moderate Deep Sleep)
Stage 3 (Moderate Deep Sleep)
• Over 50% of the recording is delta rhythm. Spindles are
rare.
• Arousal at this stage can be correlated with sleep
disorders (somnambulism, nocturnal terror, or enuresis),
and can cause confusion.
• Occasionally, spikes in temporal lobe epilepsy will only
appear in stage 3 and 4 sleep
Stage 4 (Very Deep Sleep)
Stage 4 (Very Deep Sleep)
• EEG reveals low-voltage activity, polyrhythmic waves,
slower alpha waves, and short bursts of “saw-tooth
waves” over the frontal or vertex leads (Box B), and quick
lateral eye movement (Box A).
• Appearance of REM sleep in routine EEG is seen in
narcolepsy and in patients who are withdrawn from CNS
depressants such as alcohol or phenobarbital
REM Sleep
REM Sleep
• K complexes contain 3 components including sharp, slow,
and fast.
• They are seen in stage 2 sleep and arousal.
• The K complexes are largest in older children and
adolescence.
• With increasing age, the K complexes show the
decreasing voltage with tiny superimposed spindle-like
waves
K Complexes
K Complexes
• Subdural recording showing a run of vertex waves and widely
distributed K-complexes, maximally expressed in the parietal
lobe during arousal.
• Harmonic of the sleep spindles is frequently seen in intracranial
EEGs.
• In addition, the sleep spindles usually are sharper in
morphology as the scalp and skull act as a high-frequency filter
and pass lower frequencies more efficiently than higher
frequencies.
• Disappearance during wakefulness
• helps to differentiate the K-complexes from low-voltage fast
ctivity.
• All normal EEG rhythms in the scalp EEG can be seen in the
intracranial EEG.
Subdural EEG Monitoring; K-Complex During
Arousal
Subdural EEG Monitoring; K-Complex During Arousal
• The differentiation of physiologic waveforms and
pathologic waveforms is extremely important in
intracranial EEG recording (open arrow-epileptiform in
depth electrode; arrow-sleep spindles; double arrows-
vertex waves).
• Harmonic and sharp morphology of the physiologic
waveforms in an intracranial EEG make distinguishing
between onepileptiform and epileptiform activities more
difficult.
• Disappearance of spindles and vertex waves during
wakefulness, distribution, and morphology help to diff
erentiate them from epileptiform activity, especially
between sleep spindles and low-voltage fast epileptiform
activity
Pathologic vs Physiologic Wave
Forms in Intracranial EEG
Pathologic vs Physiologic Wave Forms in Intracranial
EEG
• K-complex first appears at 4 months of age.
• They have high amplitude but their rise is not as abrupt
and the configuration isnot as sharp as one seen in older
children
Early K-Complex (16 Week CA)
Early K-Complex (16 Week CA)
• Sleep spindles arise from synchronized activity in
functionally important neuronal networks linking the
thalamus and the cortex.
• Spindles result from rhythmic spike bursts in inhibitory
(GABAergic) thalamic reticular neurons that induce
rhythmic rebound bursting in cortical neurons. This
process has been shown to result in effective
deafferentiation of the cerebral cortex.
• Cortical neurons show enhanced responsiveness and
properties of synaptic plasticity that may have a role in
memory and learning processes.
• At 1.5 to 2 months, 14/sec spindles are first seen
Normal Sleep Spindles (2 Months); Definite
14/sec Spindles
Normal Sleep Spindles (2 Months); Definite 14/sec Spindles
• EEG of an 8-week-old full-term boy shows low-voltage
22–24 Hz biphasic beta activity diffusely in the central
vertex and bilateral central-parietal areas.
• This exceptional waveform most likely represents a
harmonic of sleep spindles.
• More commonly spindles occur independently from faster
18–25 Hz activity and both patterns may be seen at the
same time
Normal Sleep Spindles (8 Weeks CA);
Harmonic of Sleep Spindles
Normal Sleep Spindles (8 Weeks CA); Harmonic of
Sleep Spindles
• Trace alternant disappears in the first month of life.
• Sleep spindles usually appear in the second months of life
with frequency between 12 and 15/sec. Throughout
infancy, they are maximal over the central and parietal
areas with shifting asymmetry.
• They usually are electronegative with a rounded positive
component.
• A complete absence of spindles at age 3–8 months
indicates a severe abnormality
Normal Sleep Spindles (10 Weeks CA)
Normal Sleep Spindles (10 Weeks CA)
• Between the ages of 3–6 months, sleep spindles appear
to be biphasic and occur as prolonged runs, up to 10–15
sec.
• The prolonged run of spindles is a very useful
developmental marker and is rarely seen beyond this age
range
Normal Sleep Spindles (3-6 Months CA);
Prolonged Runs of Spindles
Normal Sleep Spindles (3-6 Months CA); Prolonged Runs of
Spindles
• Between the ages of 3–6 months, sleep spindles appear
to be biphasic and occur as prolonged runs, up to 10–15
sec.
• The prolonged run of spindles is a very useful
developmental marker and is rarely seen beyond this age
range
Prolonged Sleep Spindles (3-6 Months
CA)
Prolonged Sleep Spindles (3-6 Months CA)
• Between the ages of 3–6 months, sleep spindles appear
to be biphasic and occur as prolonged runs, up to 10–15
sec.
• The prolonged run of spindles is a very useful
developmental marker and rarely seen beyond this age
range.
Prolonged Sleep Spindles (3-6 Months
CA)
Prolonged Sleep Spindles (3-6 Months CA)
• Between the ages of 3–6 months, sleep spindles appear
to be biphasic and as prolonged runs, up to 10–15 sec.
• The prolonged run of spindles is a very useful
developmental marker and rarely seen beyond this age
range.
• Throughout infancy, sleep spindles are maximal over the
central and parietal areas with shifting asymmetry.
• They usually shows electronegative with rounded positive
component that is a typical hallmark of sleep spindles in
infancy.
• These surface-negative spindles with wicket or comb-like
shape can be erroneously interpreted as 14/sec positive
spikes (below)
Normal Sleep Spindles (16 Weeks
CA)
Normal Sleep Spindles (16 Weeks CA)
Sleep Spindles with subharmonic
• Subharmonic of
sleep spindles
with a frequency
approximately
half that of sleep
spindles with a
notched
appearance can
be seen.
• The subharmonic
has the same
reaction and
distribution as
sleep spindles
Sleep Spindles with Subharmonic
• Mitten patterns are seen during sleep and consist of a
sharply-contoured waveform on the slope of a slow wave
of the same polarity that resemble a mitten, with the
thumb of the mitten formed by the last wave of a spindle
and the hand portion by the slower wave component.
• Mittens are a variant of a vertex wave or K-complex and
should not be mistaken for a spike-and-wave discharge.
• It is best seen in the referential montage and in stage 3
sleep
Mitten Pattern
Mitten Pattern
Mitten Pattern
Mitten Pattern
Mitten Pattern
• Hypnagogic hypersynchrony is an activity seen in early
drowsiness and in arousal from deeper sleep.
• It is characterized by bilateral synchronous, high voltage,
rhythmic 3-5 Hz activity.
• This activity first appears at the age of 2 to 3 months and
becomes prominent and continuous at 9 months.
• At age 4 years, it becomes shorter in duration and more
paroxysmal in appearance
•
Hypnagogic Hypersynchrony
• By age 9 to 11 years, it becomes rare. Although the
presence of hypnagogic hypersynchrony at age 12 years
is considered abnormal by some authors,21 it may be
seen in normal children up to the age of 12-13 years.
• The frequency of hypnagogic hypersynchrony is 3-4 Hz
at the age of 2-3 months and increases to 4-5 Hz in older
children.
• This EEG also shows slow eye movement (SEM),
maximally seen at F7 and F8, which is also one of the
signs of drowsiness.
Hypnagogic Hypersynchrony
Hypnagogic Hypersynchrony
• Nearly continuous hypnagogic hypersynchrony in a 22-
month-old infant.
• Hypnagogic hypersynchrony appears at approximately 3
months of age and is characterized by monorhythmic,
slow generalized activity with the frequency of 3-4 Hz
during drowsiness.
• It may be seen in olderchildren up to 12-13 years but is
rare after 11 years (incidence of only 10%).
• The frequency increases to 4-5 Hz in older children
Hypnagogic Hypersynchrony
Hypnagogic Hypersynchrony
• EEG of a 25-month-old boy with asymmetric hypnagogic
hypersynchrony with shifting predominance.
• The paroxysmal bursts of generalized high-voltage,
rhythmically monotonous theta activity superimposed on
low-voltage background activity, so-called “hypnagogic
hypersynchrony,” is the hallmark of drowsiness in early
childhood.
• Occasionally, small sharp or spiky discharges may be
interspersed between the theta waves.
•
Asymmetric Hypnagogic Hypersynchrony
• These discharges should not be interpreted as
epileptiform activity unless they are definitely distinct from
background activity and not only occur during drowsiness
or at the onset of sleep but also persist into deeper stages
of sleep.
• Asymmetric hypnagogic hypersynchrony with shifting
predominance can be seen and is not considered
abnormal
Asymmetric Hypnagogic Hypersynchrony
Asymmetric Hypnagogic Hypersynchrony
Hypnagogic Hypersynchrony
• EEG of a 4-year-old boy with hypnagogic hypersynchrony.
• The paroxysmal bursts of generalized high-voltage,
rhythmically
• monotonous theta activity superimposed on low-voltage
background activity, so-called “hypnagogic hypersynchrony” is
the hallmark of drowsiness in early childhood.
• Occasionally, small sharp or spiky discharges may be
interspersed between the theta waves.
• These discharges should not be interpreted as epileptiform
activity unless they are definitely distinct from background
activity and not only occur during drowsiness or at the onset of
sleep but also persist into deeper stages of sleep
Hypnagogic Hypersynchrony
Hypnic Myoclonia (HM) (Sleep Starts or Hypnogogic
Jerks)
• Video-EEG of a 5-year-old boy with well-controlled focal
epilepsy shows a burst of high-voltage 3–4 Hz delta activity
intermixed with low-amplitude spikes during chin quivering (*).
• This EEG pattern is compatible with hypnagogic
hypersynchrony associated with HM.
• This wake-to-sleep transition event is characterized by a
sudden, single, brief muscular contraction of the legs and
occasionally the arms, head, and postural muscles.
• Hypnagogic hallucinations often occur before the sleep starts,
and the perception of falling may occur, ending with the
myoclonic jerk.
• HM is a physiologic fi nding unless it is frequent and results in
sleep-onset insomnia. It also must be diff erentiated from
seizure, especially if it occurs in patients with known epilepsy.
Hypnic Myoclonia (HM) (Sleep Starts or Hypnogogic
Jerks)
• HM occurs in 60–79% of normal individuals.
• Ninety percent of patients stop these movements by age
4 years.
• It is more common in boys than in girls by 4:1.
• It may be frightening when observed by a parent,
• especially if associated with a vocalization or cry.
• Injury from the massive movement is rare, but foot injuries
secondary to kicking a bedpost or crib rail may occur
Hypnic Myoclonia (HM) (Sleep Starts or Hypnogogic
Jerks)
• EEG of a 5-year-old asymptomatic boy shows 14- and 6
Hz positive spikes (arrow head) immediately after
hypnagogic hypersynchrony (open arrow).
• Fourteen and six hertz positive spikes (arrow head) are
commonly seen during drowsiness.
14-and-6-Hertz Positive Spikes;
Hypnagogic Hypersynchrony
14-and-6-Hertz Positive Spikes; Hypnagogic Hypersynchrony
• An 8-year-old boy with recurrent syncope without other
associated symptoms suspicious of seizures or other
neurologic conditions except borderline ADHD.
• There was a history of GTCS in his 4-year-old brother.
• EEG during drowsiness shows hypnagogic
hypersynchrony and bilateral-independent centro-
temporal spikes. Characteristic spikes over the rolandic
area are regarded as neurobiological markers of BECTS.
• However, rolandic (centro-temporal) spikes have been
reported in normal children without clinical seizures or
neurologic manifestations.
Asymptomatic Centro-Temporal Spikes;
Hypnagogic Hypersynchrony
• They are seen in 1.2–3.5% of normal healthy children in
the community36,37 and 6–34% of siblings of patients aff
ected by BECTS
• The risk of epilepsy is higher if rolandic spikes remain
unilateral during sleep, rolandic spikes continue during
REM sleep, and if they occur in the presence of
generalized spike-wave discharges.
• The frequency of rolandic spikes in children with ADHD
(3–5.6%) is significantly higher than expected from
epidemiologic studies although how ADHD symptoms are
related to rolandic spikes is still unclear
Asymptomatic Centro-Temporal Spikes;
Hypnagogic Hypersynchrony
Asymptomatic Centro-Temporal Spikes; Hypnagogic
Hypersynchrony
• Video-EEG of a 5-year-old boy with well-controlled focal epilepsy
shows a burst of high-voltage 4 Hz delta activity intermixed with
low-amplitude spike-like during right arm jerks (arrow).
• This EEG pattern is compatible with hypnagogic hypersynchrony
and the right arm jerking is most likely to be hypnic myoclonia.
• Sleep starts (hypnic myoclonia) also have been termed
“hypnagogic jerks”.
• This wake-to-sleep transition event is characterized by a sudden,
single, brief muscular contraction of the legs and occasionally the
arms, head, and postural muscles.
• Sensory hallucinations (hypnagogic hallucinations) often occur
before the sleep start, and the subjective perception of falling may
occur, ending with the myoclonic jerk.
Hypnic Myoclonia; Hypnagogic
Hypersynchrony.
• Sleep starts are common, occur in most individuals, and are
not pathologic unless they are frequent and result in sleep-
onset insomnia.
• They also must be differentiated from seizure, especially if they
occur in patients with known epilepsy.
• Hypnic myoclonia occurs in 60–79% of normal individuals.
• Although it may occur at any age, 90% of patients stop these
movements by age 4 years.
• They are more common in boys than girls by 4:1.
• It may be frightening when observed by a parent, especially if
associated with a vocalization or cry.
• Injury from the massive movement is rare, but foot injuries
secondary to kicking a bedpost or crib rail may occur
Hypnic Myoclonia; Hypnagogic
Hypersynchrony.
Hypnic Myoclonia; Hypnagogic Hypersynchrony.
• Focal rhythm over the midline region, most prominent
over vertex with occasional spread to adjacent electrodes
• Usually 5-7 Hz, monorhythmic, waxes and wanes
• Seen in wakefulness and drowsiness- has variable
reactivity
• Occurs in a heterogeneous group of patients
• May be more common in frontal lobe epilepsy if
pathologic
Midline theta
Midline theta
Midline Theta
• Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the
frontal regions during arousal from sleep in children.
• The FAR is characterized by 30–150 μV, predominantly
monophasic negative waves, occurring in bursts or runs lasting
up to 13 sec (usually 1–5 sec) with a characteristic notching of
the ascending or descending phase of each wave.
• The notched appearance may represent harmonics of the
waveforms.
• The waxing and waning of the amplitude often leads to a
spindle-like morphology.
• The FAR appears at the F3 and F4 electrodes with minimal
spread to nearby scalp areas.46 The incidence of the FAR in a
normal population is unknown.
• Although it was first reported in children with minimal cerebral
dysfunction or a seizure disorder, it is later considered to be a
non specifi c EEG pattern of no clinical significance
Frontal Arousal Rhythm (FAR)
Frontal Arousal Rhythm (FAR)
• EEG of an 8-year-old girl with idiopathic generalized epilepsy.
• Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions
during arousal from sleep in children between ages 2 and 12 years, mainly 2 and
4 years.
• The FAR is characterized by 30–150 μV predominantly monophasic negative
waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec),
maximally over the frontal midline, with a characteristic notching of the ascending
or descending phase of each wave.
• The notched appearance may represent harmonics of the waveforms. Waxing
and waning of the amplitude often leads to a spindle-like morphology. The FAR
appears at the F3 and F4 electrodes with minimal spread to nearby scalp areas.
• The incidence of the FAR in the normal population is unknown.
• Although it was first reported in children with minimal cerebral dysfunction or a
seizure disorder, it is now considered to be a nonspecific EEG pattern of no
clinical significance
Frontal Arousal Rhythm (FAR)
Frontal Arousal Rhythm (FAR)
• An 8-year-old girl with a history of GTCS. EEG demonstrates trains of
rhythmic 6-Hz sharp waves in bifrontal regions during arousal state.
• Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the
frontal regions during arousal from sleep in children.
• The FAR is characterized by 30–150 μV, predominantly monophasic
negative waves, occurring in bursts or runs lasting up to 13 sec
(usually 1–5 sec) with a characteristic notching of the ascending or
descending phase of each wave.
• The notched appearance may represent harmonics of the waveforms.
The waxing and waning of the amplitude often leads to a spindle-like
morphology.
• The FAR appears at the F 3 and F 4 electrodes with minimal spread
to nearby scalp areas.46 The incidence of the FAR in a normal
population is unknown.
• Although it was first reported in children with minimal cerebral
dysfunction or a seizure disorder, it is now considered to be a
nonspecific EEG pattern of no clinical significance
Frontal Arousal Rhythm (FAR)
Frontal Arousal Rhythm (FAR)
• EEG of a 10-year-old boy with idiopathic generalized epilepsy.
• Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions during
arousal from sleep in children between ages 2 and 12 years, mainly 2 and 4 years.
• The FAR is characterized by 30–150 μV predominantly monophasic negative waves,
occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec), maximally over the
frontal midline, with a characteristic notching of the ascending or descending phase of
each wave.
• The notched appearance may represent harmonics of the waveforms.
• Waxing and waning of the amplitude often leads to a spindle-like morphology.
• The FAR appears at the F3 and F4 electrodes with minimal spread to nearby scalp
areas.
• The incidence of the FAR in a normal population is unknown.
• Although it was first reported in children with minimal cerebral dysfunction or a seizure
disorder, it is now considered to be a nonspecific EEG pattern of no clinical significance
Frontal Arousal Rhythm (FAR)
Frontal Arousal Rhythm (FAR)
• EEG of a 6-year-old boy with frontal lobe epilepsy during
arousal from sleep.
• Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the
frontal regions during arousal from sleep in children between
ages 2 and 12 years, mainly 2 and 4 years.
• The FAR is characterized by 30–150 μV predominantly
monophasic negative waves, occurring in bursts or runs lasting
up to 13 sec (usually 1–5 sec), maximally over the frontal
midline, with a characteristic notching of the ascending or
descending phase of each wave.
• The notched appearance may represent harmonics of the
waveforms.
• Waxing and waning of the amplitude often leads to a spindle-
like morphology.
Frontal Arousal Rhythm (FAR)
• The FAR appears at the F3 and F4 electrodes with
minimal spread to nearby scalp areas.
• The incidence of the FAR in a normal population is
unknown. Although it was first reported in children with
minimal cerebral dysfunction or a seizure disorder, it is
now considered to be a nonspecific EEG pattern of no
clinical significance.
• Its mildly abnormal character is likely, but its clinical
significance was thought to be debatable
• Hughes found 70% of patients having epileptic seizures
and demonstrated a case in which FAR representing ictal
electrographic seizure activity
Frontal Arousal Rhythm (FAR)
Frontal Arousal Rhythm (FAR)
• RTTD is seen in 0.5–2.0% of normal adult population and less
common in adolescence.
• It is described as bursts or runs of rhythmic, 5–7 Hz (typically
5–5.5 Hz), theta activity with flat-topped, sharply contoured,
often notched appearance in the temporal regions, maximally
expressed in the mid anterior temporal electrode.
• The sharper component of the wave usually has a negative
polarity in the anterior temporal region.
• It can occur unilaterally, bilaterally, or shifting from side to side
with gradual onset and off set.
Rhythmic Temporal Theta Bursts of Drowsiness (RTTD);
Rhythmic Mid temporal Discharges (RMTD); (Psychomotor
Variant)
• The pattern is distinguished from ictal epileptiform activity because it
is monomorphic and mono rhythmic (no evolution into other
frequencies), does not alter background activity, occurs in relaxed
wakefulness and drowsiness (most common), and disappears in
deeper levels of sleep.
• This pattern has no clinical significance.
• However, it was considered by some authors to be a pathologic
finding in selected cases.
• This pattern was previously called “psychomotor variant.
• They are also now called “rhythmic mid temporal discharges
(RMTDs)
Rhythmic Temporal Theta Bursts of Drowsiness (RTTD);
Rhythmic Mid temporal Discharges (RMTD); (Psychomotor
Variant)
Rhythmic Temporal Theta Bursts of Drowsiness
(RTTD); Rhythmic Mid temporal Discharges
(RMTD); (Psychomotor Variant)
• A 15-year-old girl with recurrent passing out episodes.
• EEG during drowsiness shows rhythmic 5-6 Hz, theta
activity with flat-topped, sharply contoured over the
temporal regions with a phase reversal in the posterior
temporal electrodes.
• Rhythmic temporal theta waves of drowsiness (RTTD) is
also called rhythmic mid temporal discharges (RMTDs) or
psychomotor variant.
• RTTD is seen in adult and, less commonly, in adolescent.
Rhythmic Temporal Theta Bursts
of Drowsiness (RTTD)
• This EEG pattern is distinguished from ictal epileptiform
activity in that it is monomorphic and mono rhythmic (no
evolution), does not affect background activity, and occurs
in only in relaxed wakefulness and drowsiness.
• This EEG pattern is of uncertain significant
Rhythmic Temporal Theta Bursts
of Drowsiness (RTTD)
Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
• A 16-year-old girl with recurrent vertigo who had been
diagnosed with simple partial seizures and was treated
with carbamazepine.
• The treatment failed to stop the symptoms and caused
side effects.
• Brain MRI was unremarkable.
• EEGs were performed four times in the past and were
interpreted as epileptiform activity in the temporal regions.
• This EEG during drowsiness shows a burst of rhythmical
5.5 Hz theta activity in the left temporal region (open
arrow) with negative polarity of the sharper component of
the burst in the midtemporal region.
Rhythmic Temporal Theta Bursts of
Drowsiness (RTTD)
• Note no disruption of alpha rhythm in the left occipital
region (arrow heads).
• The patient was completely normal throughout the
discharge.
• This EEG pattern is compatible with RTTD and is
considered a normal variant and has no clinical
significance.
• The patient has done well since stopping carbamazepine
Rhythmic Temporal Theta Bursts of
Drowsiness (RTTD)
Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
• A 17-year-old boy with recurrent headache and numbness
of his right arm.
• EEG during resting wakefulness shows bilateral-
independent 5.5 Hz theta activity in the temporal regions
in the 2 hemispheres.
• As the discharge proceeds, the morphology does not
change (monomorphic and monorhythmic).
• The discharge continues during drowsiness but
disappears in stage 2 sleep.
• These differentiate the RTTD from focal ictal activity
Rhythmic Temporal Theta Bursts of
Drowsiness (RTTD)
Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
• A 17-year-old boy with a new-onset GTCS.
• EEG during drowsiness shows runs of bilateral-independent 5.5
Hz sharply-contoured theta activity in the midtemporal regions
in the two hemispheres.
• As the discharge proceeds, the morphology does not change
(monomorphic and monorhythmic).
• The discharge continues during drowsiness but disappears in
stage 2 sleep.
• These findings differentiate the RTTD from focal ictal activity.
Rhythmic Temporal Theta Bursts of
Drowsiness (RTTD)
Rhythmic Temporal Theta Bursts of
Drowsiness (RTTD)
• EEG during drowsiness shows long runs of monomorphic and
monorhythmic notched theta activity that does not evolve into
other frequencies or waveforms.
• The patient was completely normal throughout the run of
discharge.
• The discharge disappears during deeper states of sleep.
• These findings differentiate RTTD from an electrographic
seizure.
• Note an unusual morphology of the discharge that shows
positive polarity in the posterior temporal areas.
Rhythmic Temporal Theta Bursts of
Drowsiness (RTTD)
Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
• This EEG pattern is defined as bursts of arch shaped waves at
13–17 Hz and/or 5–7 Hz, most commonly at 14 and/or 6 Hz,
seen generally over the posterior temporal and adjacent areas
of one or both sides of the head during deep drowsiness and
very light sleep.
• The sharp peaks of its components are electropositive
compared to other regions. The bursts have a widespread field
and last for 0.5–1 sec.
• This EEG pattern occurs in children from the age of 3 up to
young adulthood but more commonly occur between 12 and 20
years with a peak at age 13–14 years. It is best displayed in
the contralateral ear reference montage.
• 14 and 6/sec positive spike discharge is a benign variant of no
clinical significance
14 and 6/sec Positive Spike Discharge
14 and 6/sec Positive Spike Discharge
• Fourteen and six per second positive spike discharge
shows mainly 13 Hz positive spikes
14 and 6/sec Positive Spike Discharge
14 and 6/sec Positive Spike Discharge
14 and 6/sec Positive Spike Discharges;
(Anterior-Posterior Bipolar)
• This EEG pattern is defined as bursts of arch shaped
waves at 13–17 Hz and/or 5–7 Hz, most commonly at 14
and/or 6 Hz, seen generally over the posterior temporal
and adjacent areas of one or both sides of the head
during deep drowsiness and very light sleep (arrow).
• The sharp peaks of its components are positive with
respect to other regions.
• This pattern occurs in the children after age 3 to young
adult with a peak at age 13–14 years.
• This pattern is a benign variant of no clinical significance
14 and 6/sec Positive Spike Discharges;
(Anterior-Posterior Bipolar)
14 and 6/sec Positive Spike Discharges;
(Contralateral Ear Reference)
• The 14 and 6/sec positive spike discharges are best seen
during a contralateral ear reference run
14 and 6/sec Positive Spike Discharges;
(Contralateral Ear Reference)
• A 12-year-old boy with symptomatic Lennox-Gastaut syndrome
after the treatment of status epilepticus with intravenous
midazolam.
• EEG showed continuously diff use polymorphic delta activity
with superimposed “14-and-6-Hertz positive spikes.”
• Although 14- and 6 Hz positive spikes in diff use
encephalopathy EEG pattern was once thought to be seen
exclusively in coma due to Reye’s syndrome
• in other encephalopathies of childhood as well suggesting that
they are epiphenomena or a resilient normal.
• The 14- and 6 Hz positive spikes are best seen in contralateral
ear reference montage.
14-and-6-Hertz Positive Spikes;
Diffuse Encephalopathy
14-and-6-Hertz Positive Spikes;
Diffuse Encephalopathy
• With contralateral ear reference, 14- and 6 Hz positive
spikes (arrow head) are diffusely seen over both
hemispheres but maximal in the right posterior temporal
region.
• The opposite polarity in the EEG electrodes over the left
hemisphere may be suggestive of the dipole character of
this waveform
14-and 6-Hz Positive Spikes
14-and 6-Hz Positive Spikes
• Diff use 14 and 6/sec positive spike discharges with right
hemispheric predominance during referential run in a 12-
year-old adolescent girl with non epileptic events
14 and 6/sec Positive Spike Discharge;
Referential Montage
14 and 6/sec Positive Spike Discharge; Referential Montage
• When a 14 and 6/sec positive spike discharge is
intermixed with diff use delta or theta slowing, it can
simulate spike-wave or poly spike-wave activity
14 and 6/sec Positive Spike Discharge; Poly
spike-Wave-Like Discharge
14 and 6/sec Positive Spike Discharge; Poly
spike-Wave-Like Discharge
• Fourteen and six hertz positive spikes (**) can be mixed with sleep
spindles (*).
• These 2 waveforms can be differentiated from each other by
configuration and distribution.
• Fourteen and six hertz positive spikes occur predominantly during
drowsiness and light sleep and consist of short trains of arch-shaped
waveforms with alternating positive spiky components and a negative,
smooth, rounded waveform.
• a 14 and 6/sec positive spike maximal amplitude over the posterior
temporal region.
• Sleep spindles occur predominantly during stage 2 sleep and consist
of trains of sinusoidal waveforms.
• It usually has maximal amplitude over the fronto-central region
14-and-6-Hertz Positive Spikes
14-and-6-Hertz Positive Spikes
• During a subdural EEG recording in the patient with right
neocortical temporal lobe epilepsy, 14 and 6/sec positive spikes
are noted in the right anterior temporal region (open arrow)
outside of the epileptogenic zone (blue).
• This is an uncommon location of this EEG pattern that is
usually seen in the posterior temporal region.
• This may be due to brain plasticity.
• The patient has been seizure free since the epileptogenic zone,
excluding the area containing 14 and 6/sec positive spike
discharge, was resected.
• This strongly supports the benign nature of this EEG pattern.
• The 14 and 6/sec positive spikes EEG pattern has never been
reported in the literature.
14-and 6-Hertz Positive Spikes
(Subdural EEG Monitoring)
14-and 6-Hertz Positive Spikes (Subdural
EEG Monitoring)
• Small sharp spike (SSS) is a benign EEG pattern that is
seen in 20–25% of a normal adult population.
• SSS are seen in adults during drowsiness or light sleep.
• They are usually low voltage, short duration, single
monophasic or biphasic spike with an abrupt ascending
limb and a steep descending limb.
• The prominent after coming slow wave may not occur.
• SSS occur unilaterally or bilaterally
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS
• A 16-year-old girl with a history of migraine who presented
with recurrent passing out episodes. EEG obtained during
light non-REM sleep shows low voltage, short duration,
biphasic spikes with an abrupt ascending limb and a
steep descending limb.
• The negative and positive components are of
approximately equally spiky character.
• The spikes are widely distributed in both hemispheres (*).
• Small sharp spikes (SSS) or BETS occur almost
exclusively during drowsiness or light non-REM sleep.
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS)
• A prevalence of 1.36% was found in adult with a peak
between ages 30 and 40.
• It is uncommonly seen in adolescents.
• There is a debate whether this is a normal or an
epileptogenic pattern.
• In nonepileptics, these discharges may be seen in stroke,
syncopal attacks, and psychiatric patients
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS)
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS)
• A 17-year-old-right-handed girl with recurrent episodes of
deja vu. The presurgical work-up was consistent with right
mesio-temporal epilepsy.
• EEG shows frequent small sharp spikes (SSS) during
drowsiness and light sleep (arrow head).
• The patient has been seizure free since the right anterior
temporal lobectomy.
• “Small sharp spikes (SSS)” is a benign EEG pattern that
is seen in 20–25% of
• a normal adult population.
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS); Benign Sporadic Sleep
Spikes (BSSS)
• SSS are seen in adults during drowsiness or light sleep,
usually low voltage (less than 50 μV), short duration, single
monophasic or biphasic spikes with an abrupt ascending limb
and a steep descending limb.
• The prominent after coming slow wave may not occur.
• SSS are almost always bilaterally represented, either ccurring
independently or having reflection to the opposite hemisphere.
• The bilateral occurrence of the SSS should not be
misinterpreted as bilateral epileptogenic foc
Small Sharp Spikes (SSS); Benign Epileptiform
Transients of Sleep (BETS); Benign Sporadic Sleep
Spikes (BSSS)
Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep
(BETS); Benign Sporadic Sleep Spikes (BSSS)
• A 9-year-old girl with right mesio-temporal epilepsy caused by
mild MCD.
• She has been seizure free since the left temporal lobectomy.
EEG during drowsiness shows diff use SSS, predominantly in
the left hemisphere.
• “Small sharp spikes (SSS)” is a benign EEG pattern that is
seen in 20–25% of a normal adult population.
• SSS are seen in adults during drowsiness or light sleep,
usually low voltage, short duration, single monophasic or
biphasic spikes with an abrupt ascending limb and a steep
descending limb. The prominent after coming slow wave may
not occur. SSS occur unilaterally or bilaterally.
• Some authors believed this pattern indicates a “moderate
degree of epileptogenicity.
Small Sharp Spikes (SSS)
Small Sharp Spikes (SSS)
• This EEG pattern can be seen in 2.5% of both adolescents and
young adults.
• It occurs during relaxed wakefulness, drowsiness, and light
sleep and disappears during deeper stages of sleep.
• It is described as bursts of 1–2 sec duration, diff use, low
voltage, 5–7 Hz, spike-and-wave discharges, commonly
bifrontally or occipitally.
• At times, spikes are difficult to see.
• This EEG pattern is regarded as a benign variant of uncertain
• significance.
• Six-hertz spikes with minimal or no associated waves may
represent a transitional pattern between 6-Hz spike-wave
bursts and 14 and 6 Hz positive bursts.
Six-Hertz Spike-and-Wave Bursts; (Phantom Spike-
and-Wave Discharge)
Six-Hertz Spike-and-Wave Bursts; (Phantom Spike-and-
Wave Discharge)
• Six-hertz spike and wave bursts in an 11-year-old girl with
recurrent syncopal attacks associated with migraine.
• Six-hertz spike and wave bursts (arrow) can be very
difficult to distinguish from atypical spike-wave activity.
• The clue to make a distinction is that benign 6-Hz spike
and wave bursts occur during relaxed wakefulness and
drowsiness and disappear during deeper stages of sleep.
• Two types of 6-Hz-spike-and-wave discharges have been
described, FOLD (Female, Occipital, Low amplitude,
Drowsiness) and WHAM (Wake, High-amplitude, Anterior,
Male).
• FOLD is more benign, and WHAM is more likely to be
associated with seizures
Six-Hertz Spike-and-Wave Bursts
Six-Hertz Spike-and-Wave Bursts
• Wicket waves are one of the most common over-read EEG
patterns64 seen almost exclusively in adults, most commonly
>30 years of age and, usually older than 50 years.
• Wicket waves are relatively rare with an incidence of 0.9%.
• It occurs in clusters or trains, but also as single sharp
transients, of 6- to 11-Hz negative sharp aciform waves with
amplitude of 60–200 μV.
• They are seen over the anterior or midtemporal regions during
relaxed wakefulness but facilitated by drowsiness and may
occur in light sleep.
• Wicket waves occur unilaterally with a shifting asymmetry
between the two hemispheres.
• During the waking portion of the record, wicket waves are often
• masked by background EEG activity.
• Recently, wicket waves have also been reported to occur
during REM sleep
Wicket Wave
• Their cardinal feature is a changing mode of occurrence through any single recording,
from intermittent trains of more or less sustained, aciform, discharges resembling mu
rhythm, to sporadic single spikes.
• Amplitude may be high, but the transient arises out of an ongoing rhythm and does
not stand out.
• When occurring singly, wicket waves can be mistaken for anterior or mid-temporal
spikes.
• Isolated wicket wave(s) can be differentiated from epileptiform discharge (s) by the
following criteria:
• (1) no slow wave component following the wicket wave;
• (2) occurring in trains or in isolation
• and do not disrupt the background;
• (3) having a similar morphology to the waveforms in the train when they occur as a
single spike.
• Wicket wave is considered a benign variant pattern and is not associated with
epilepsy
Wicket Wave
Wicket Wave
• A 12-year-old-right-handed boy with medically intractable epilepsy caused
by nonaccidental trauma in infancy.
• Interictal EEG shows trains of negative sharp arciform waves in the right
anterior temporal region (box), continuously low-amplitude polymorphic
delta activity (PDA), and suppression of background activity over the right
hemisphere, maximal in the temporal region.
• The trains of sharp waves are similar to “wicket waves.”
• MRI demonstrates multifocal encephalomalacia but maximal over the right
anterior temporal region (open arrow).
• Wicket waves are most commonly seen in individuals older than 30 years
of age.
• Wicket waves are relatively rare with a prevalence of 0.9% in adults but
unknown in children.
• They occur in clusters or trains, but also as single sharp transients, of mid-
or anterior temporal 6–11 Hz negative sharp arciform waves with amplitude
of up to 200 μV.
Wicket-Wave Like Waveform; Non
accidental Trauma
• Wicket waves can be differentiated from temporal lobe
epileptiform discharges based on the following criteria:
• (1) no slow wave component following wicket spikes;
• (2)occurring intrains or in isolation and do not disrupt the
background;
• (3) having a similar morphology to the waveforms in the
train when they occur as a single spike.
• Wicket waves are more commonly seen in patients with
cerebrovascular disease.
• In this EEG, the age and abnormal background activity
are strongly against the diagnosis of wicket waves and
supportive of epileptiform activities.
Wicket-Wave Like Waveform; Non
accidental Trauma
Wicket-Wave Like Waveform; Non
accidental Trauma
• A 4-month-old boy who developed a right-sided focal motor seizure
after cardiac surgery for complex congenital heart defects.
• MRI with DWI shows cerebral infarction in the left fronto-temporal
region.
• Interictal EEG shows trains of negative sharp arciform waves in
the left posterior temporal region (box) and suppression of
background activity over the left hemisphere.
• The trains of sharp wave configuration are similar to “wicket
waves.”
• Wicket waves are most commonly seen in individuals older than 30
years of age.
Wicket-Wave Like Waveform; Left Frontal-
Temporal Infarction
• Wicket waves are relatively rare with a prevalence of 0.9% in adult
but unknown in children.
• They occur in clusters or trains, but also as single sharp transients,
of mid- or anterior temporal 6–11 Hz negative sharp arciform waves
with amplitude of up to 200 μV.
• Wicket waves can be differentiated from temporal lobe epileptiform
discharges based on the following criteria:
• (1) no slow wave component following wicket spikes;
• (2) occurring in
• trains or in isolation and do not disrupt the background;
• (3) having a similar morphology to the waveforms in the train when
occurs as a single spike.
Wicket-Wave Like Waveform; Left Frontal-
Temporal Infarction
• In this EEG, the age and abnormal background activity
are strongly against the diagnosis of wicket waves but
supportive of epileptiform activities.
• In adult, wicket waves are more common seen in patients
with cerebrovascular disease
Wicket-Wave Like Waveform; Left Frontal-
Temporal Infarction
Wicket-Wave Like Waveform; Left Frontal-
Temporal Infarction
Reference: Atlas of pediatric EEG

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Sleep activity in eeg

  • 1. SLEEP ACTIVITIES By: Mohibullah Fazli Kakar Trainee of Neurophysiology French Medical Institute for Children
  • 2. Sleep stages •Drowsiness Alpha dropout (earliest sign) • Increased beta activity over the frontocentral regions • Diff use rhythmic theta activity with anterior predominance • Slow eye movement • Mu rhythm, wicket wave, and 14 and 6 Hz positive spikes can be seen. • Deep drowsiness is marked by the vertex waves and POSTS that persist during light sleep and deep sleep • Hypnagogic hypersynchrony in 3 months to 8 years.
  • 3. Sleep stages •Stage 2 sleep • Symmetric, synchronous theta rhythms with posterior predominance, 12–15/sec spindles, vertex sharp waves, K-complexes, and POSTS. • Sleep spindles in the 12–15/sec range are hallmark of sleep onset.
  • 4. Sleep stages •Stage 3 sleep Delta frequencies in the 0.75– 3/sec range are prominent over the anterior regions. • Sleep spindle in the 10–12/sec and even in the 12– 14/sec ranges are still present but gradually become less prominent. • Rhythmic activity of 5–9/sec is common. • Rhythmic and symmetrical delta activity is noted between 20% and 50% of the recording
  • 5. Sleep stages • Stage 4 sleep • Over 50% of the recording is delta rhythm. • Spindles are rare. • Arousal at this stage can be correlated with sleep disorders (somnambulism, nocturnal terror, or enuresis), and can cause confusion. • Occasionally, spikes in temporal lobe epilepsy will only appear in stage 3 and 4 sleep.
  • 6. Sleep stages •REM sleep Low-voltage activity, polyrhythmic waves, and slower alpha waves. • Short bursts of “saw-tooth waves” over the frontal or vertex leads and quick lateral eye movements. • Appearance of REM sleep in routine EEG is seen in narcolepsy and in patients who are withdrawn from CNS depressants such as alcohol or phenobarbital
  • 7. K-Complex • Contain 3 components including sharp, slow, and fast. • Seen in stage 2 sleep and arousal. • Largest in older children and adolescence. With advanced age, the K-complexes show the decline in voltage with tiny superimposed spindle-like waves. • First appears at 4 months of age. • They have high amplitude but their rise is not as abrupt and the configuration is not as sharp as seen in older children.
  • 8. Sleep spindles • Arise from synchronized activity in neuronal networks linking the thalamus and the cortex. • Spindles result from rhythmic spike bursts in inhibitory (GABAergic) thalamic reticular neurons that induce rhythmic rebound bursting in cortical neurons resulting in effective deafferentiation of the cerebral cortex. • Cortical neurons show enhanced synaptic plasticity that might have a role in memory and learning processes. • First seen at 1.5–2 months with a frequency of 14/sec.
  • 9. Sleep spindles • Throughout infancy, they are maximal over the central and parietal areas with shifting asymmetry. • They usually are electronegative with rounded positive component that is a typical hallmark of sleep spindles in infancy. • These surface-negative spindles with wicket or comb-like shape can be erroneously interpreted as 14/sec positive spikes • Between the ages of 3 and 6 months, sleep spindles appear to be biphasic and as prolonged runs, up to 10– 15 sec. The prolonged run of spindles is a very useful developmental marker and is rarely seen beyond this age range
  • 10. Sleep spindles • Subharmonic or harmonic of sleep spindles with a frequency approximately half or double that of sleep spindles and notched appearance can be seen. • In the second half of the first year of life, the spindles appear to be monophasic and are often asynchronous between the two sides. • The frequency of spindles also changes, with 12/sec components becoming more prominent. • Asynchronous spindles may occasionally continue from 1 to 2 year of age but rarely are seen after the age of 2 years when interhemispheric synchrony of the spindles appears.
  • 11. Mitten patterns • Consist of a sharp-contoured waveform on the slope of a slow wave of the same polarity that resembles a mitten, with a thumb of mitten formed by the last wave of a spindle and the hand portion by the slower wave component. • Maximal at the frontocentral vertex with spread into parasagittal regions. • The location is different from K-complexes in that it is centered anterior to the central vertex where K-complexes are maximal. • Variant of a vertex wave or K-complex and should not be mistaken for a spike-and-wave discharge. • It is best seen in referential montage in stage 3 sleep.
  • 12. Hypnagogic hypersynchrony • Seen in early drowsiness and arousal from deeper sleep. • Characterized by bilateral synchronous, high voltage, rhythmic 3–5 Hz activity. • The frequency of hypnagogic hypersynchrony is 3–4 Hz at the age of 2–3 months and increases to 4–5 Hz in older children. • Asymmetric hypnagogic hypersynchrony with shifting predominance can be seen and is not considered abnormal. • At 2–3 months, first appears. • At 9 months, more prominent and continuous. • Between 4 months and 2 years, seen in almost all infants
  • 13. Hypnagogic hypersynchrony • Few infants do not show this pattern but show occipital or widespread rhythmical and synchronous • 4–5 Hz waves of low to medium amplitude. • At 4 years, shorter in duration and more paroxysmal. • At 9–11 years, it becomes rare (10%). • Although the presence of hypnagogic hypersynchrony • at age 12 years is considered abnormal by some • authors, it may be seen in normal children up to the age of 12– 13 years. • Occasionally, small sharp or spiky discharges may be interspersed between the theta waves. • These discharges should not be interpreted as epileptiform activity unless they are definitely distinct from background activity and not only occur during drowsiness or at the onset of sleep but persist into deeper stages of sleep.
  • 14. Hypnic myoclonia (hypnagogic jerks) • This wake-to-sleep transition event is characterized by a sudden, single, brief muscular contraction of the legs and occasionally the arms, head, and postural muscles. • Sensory hallucinations (hypnagogic hallucinations) often occur before the hypnic myoclonia. • Hypnic myoclonia occurs in 60–79% of normal population. • Although it may occur at any age, 90% of patients stop these movements by age of 4 years. • They are more common in boys than girls by 4:1.
  • 15. Midline theta rhythm • Rare nonspecific finding of no clinical significance. • Rhythmic train of 5–7 Hz theta activity occurring in the central vertex but may also be seen in the frontal vertex. • Morphology includes sinusoidal, aciform, spiky, or mu-like appearance. • Seen during wakefulness and drowsiness. • Variable reactivity to eye opening, alerting, and limb movement. • The rhythm usually lasts from 3 to 20 sec and does not evolve.
  • 16. Frontal arousal rhythm (FAR) • Rare nonspecific EEG pattern of no clinical significance. • Frontal regions (F3 and F4 electrodes with minimal spread to nearby scalp areas) during arousal from sleep in children. • Characterized by 30–150 μV, predominantly monophasic negative waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec) with a characteristic notching of the ascending or descending phase of each wave that may represent harmonics of the waveforms.
  • 17. Frontal arousal rhythm (FAR) • The waxing and waning of the amplitude often leads • to a spindle-like morphology. • 70% of patients having epileptic seizures; a reported case in which FAR representing ictal electrographic seizure activity.
  • 18. Rhythmic temporal theta bursts of drowsiness, rhythmic midtemporal discharges (RMTD), psychomotor variant • Benign variant of no clinical signifi cance. • Seen in 0.5–2.0% of normal adult population and less common in adolescence. No prevalence in childhood. • Bursts or runs of rhythmic, 5–7 Hz or 4–7 Hz (typically • 5–5.5 Hz), theta activity with fl at-topped, sharply contoured, often notched appearance in the temporal regions. • Maximally expressed in the mid- or anterior temporal • electrodes. • Monomorphic pattern with amplitude of 50–200 μV. • Duration: commonly 5–10 sec; vary from 1 to >60 sec with gradual onset and off set.
  • 19. Rhythmic temporal theta bursts of drowsiness, rhythmic midtemporal discharges (RMTD), psychomotor variant • The sharper component of the wave usually has a negative polarity in the anterior temporal region. • Unilaterally with shifting from side to side greater than bisynchronous. • Differentiated from ictal epileptiform activity by Monomorphic and monorhythmic (no evolution into other frequencies although amplitude can vary) • No alteration of background activity Occurrence in relaxed wakefulness and drowsiness (most common) and disappearancein deeper levels of sleep. • Although it has no clinical significance, it was considered by some authors to be a pathologic finding in selected cases.
  • 20. Fourteen and six per second positive spike discharge • Benign variant of no clinical significance. • Bursts of arch-shaped waves at 13–17 Hz and/or 5– 7 Hz, most commonly at 14 and/or 6 Hz. The 14 Hz • component is more commonly seen than 6 Hz. • Maximal over the posterior temporal and adjacent areas of one or both sides of the head. • Amplitude <75 μV. • Appearance in deep drowsiness and very light sleep and disappearance in deeper levels of sleep. • Electropositive of sharp component and electronegative of smooth component.
  • 21. Fourteen and six per second positive spike discharge • Widespread fi eld lasting for 0.5–1 sec. • Occurs in children after age 3 to young adult but more common between 12 and 20 years with a peak at age 13–14 years. • Best seen in contralateral ear reference montage. • Appearance in diff use encephalopathy EEG pattern in a wide variety of encephalopathies of childhood suggesting that they are epiphenomena or a resilient normal. • Frequency is more variable and can be elicited by alerting stimuli.
  • 22. Small sharp spike (SSS) or benign epileptiform transients of sleep (BETS) • Benign variant of no clinical signifi cance. • 20–25% of a normal adult population. • Appearance in deep drowsiness and very light sleep and disappearance in deeper stages of sleep. • Usually low voltage, short duration, single monophasic, or biphasic spike with an abrupt ascending limb and a steep descending limb.
  • 23. Six-hertz spike-wave bursts (phantom spike-wave) • Benign variant of no clinical signifi cance. • 2.5% of both adolescents and young adults; 0.5–1% overall. • Appearance in relaxed wakefulness, drowsiness, and light sleep and disappearance in deeper levels of sleep. • Bursts of 1–2 sec duration diff use, low voltage (<40 μV), short duration (<30 msec), 5–7 Hz, spike-andwave • discharges, commonly bifrontal or occipital. • 25% of phantom spike and wave have repetitive rate of 4 Hz.
  • 24. Six-hertz spike-wave bursts (phantom spike-wave) • At times, spikes are difficult to see. • Six-hertz spikes with minimal or no associated waves may represent a transitional pattern between • 6-Hz spike-wave bursts and 14 and 6-Hz positive bursts. • Waking, high-amplitude, anterior, male (WHAM) vs female, occipital, low-amplitude, drowsy (FOLD). • WHAM is more likely to be associated with seizures if the repetitive rate is <5 Hz or amplitude of spike greater than slow wave.
  • 25. Wicket waves • One of the most common over-read EEG patterns seen almost exclusively in adults, most commonly >30 years of age and, usually, older than 50 years. • Benign variant pattern and is not associated with epilepsy. • Rare waveform (0.9%). • It occurs in clusters or trains, but also as single sharp transients, of 6- to 11-Hz negative sharp aciform waves with amplitude of 60–200 μV. • Anterior or midtemporal regions. • Seen during relaxed wakefulness but facilitated by drowsiness and may occur in light sleep. • Recently wicket waves have also been reported to occur during REM sleep.
  • 26. Wicket waves • Unilaterally with a shifting asymmetry between the • two hemispheres. • During the wakefulness, wicket waves are often masked by background EEG activity. • Cardinal feature is a changing mode of occurrence through any single recording, from intermittent trains of more or less sustained, aciform, discharges resembling mu rhythm, to sporadic single spikes. • Amplitude may be high, but the transient arises out • of an ongoing rhythm and does not stand out
  • 27. Wicket waves • When occurring singly, wicket waves can be mistaken for anterior or middle temporal spikes. • Isolated wicket wave can be differentiated from epileptiform discharge by the following criteria: • No slow wave component following the wicket wave • Occurring in trains or in isolation and do not disrupt the background • Similar morphology to the waveforms in the train when occurring as a single spike • More commonly seen in patients with cerebrovascular disease. • The age (younger than 30 years) and abnormal background activity are strongly against the diagnosis of wicket waves and supportive of epileptiform activities
  • 28. • In older children and adults, early drowsiness is associated with • (1) alpha dropout (earliest sign) • (2) increased beta activity over the fronto-central regions • (3) diff use rhythmic theta activity with anterior predominance; • and (4) slow eye movement. • Mu rhythm, wicket wave and 14- and 6 Hz positive spikes can be seen during drowsiness. Drowsiness; Older Children and Adults
  • 29. • Drowsiness must be differentiated from increased alertness after eye opening or caused by emotional stress that can cause alpha blocking. • In such cases the slow frequency component is absent and beta frequency predominates. • Deep drowsiness is marked by the appearance of vertex waves and POSTS that persist during light sleep and deep sleep Drowsiness; Older Children and Adults
  • 31. • In older children and adults, early drowsiness is associated with • (1) alpha dropout (earliest sign); • (2) increased beta activity over the fronto-central regions (double arrows) • (3) diff use rhythmic theta activity with anterior predominance (open arrow) • and (4) slow eye movement (doublehead arrow). • Mu rhythm, wicket wave and 14- and 6 Hz positive spikes (*) can be seen during drowsiness. • Drowsiness must be differentiated from increased alertness after eye opening or caused by emotional stress that can cause alpha blocking. • In such case slow frequency component is absent and beta frequency predominates. • Deep drowsiness is marked by the appearance of vertex waves and POSTS that persist during light sleep and deep sleep Drowsiness; 14-and-6 Hertz Positive Bursts
  • 32. Drowsiness; 14-and-6 Hertz Positive Bursts
  • 33. • Stage 2 sleep shows symmetric, synchronous theta rhythms with posterior predominance, 12–15/sec spindles, vertex sharp waves, K-complex and POSTS. • The appearance of sleep spindles in the 12–15/sec range is a hallmark of sleep onset Stage 2 (Light Sleep
  • 34. Stage 2 (Light Sleep
  • 35. • Subdural recording showing the sleep spindles in the parietal lobe during sleep. • A harmonic of the sleep spindles is more frequently seen in intracranial EEG. • In addition, the sleep spindles usually appear sharper in morphology as the scalp and skull act as a high-frequency filter and pass lower frequencies more efficiently than higher frequencies. • Disappearance during wakefulness helps to differentiate the sleep spindles from low-voltage fast activity. • All normal EEG rhythms seen in the scalp EEG can be seen in the intracranial EEG Sleep Spindles During Subdural EEG Recording
  • 36. Sleep Spindles During Subdural EEG Recording
  • 37. • Delta frequencies in the 0.75–3/sec range are prominent over the anterior regions. • Sleep spindles in the 10–12/sec and even in the 12– 14/sec ranges are still present but gradually become less prominent. • Rhythmic activity of 5–9/sec is common. • Rhythmic and symmetrical delta activity occurs during 20% to 50% of the recording Stage 3 (Moderate Deep Sleep)
  • 38. Stage 3 (Moderate Deep Sleep)
  • 39. • Over 50% of the recording is delta rhythm. Spindles are rare. • Arousal at this stage can be correlated with sleep disorders (somnambulism, nocturnal terror, or enuresis), and can cause confusion. • Occasionally, spikes in temporal lobe epilepsy will only appear in stage 3 and 4 sleep Stage 4 (Very Deep Sleep)
  • 40. Stage 4 (Very Deep Sleep)
  • 41. • EEG reveals low-voltage activity, polyrhythmic waves, slower alpha waves, and short bursts of “saw-tooth waves” over the frontal or vertex leads (Box B), and quick lateral eye movement (Box A). • Appearance of REM sleep in routine EEG is seen in narcolepsy and in patients who are withdrawn from CNS depressants such as alcohol or phenobarbital REM Sleep
  • 43. • K complexes contain 3 components including sharp, slow, and fast. • They are seen in stage 2 sleep and arousal. • The K complexes are largest in older children and adolescence. • With increasing age, the K complexes show the decreasing voltage with tiny superimposed spindle-like waves K Complexes
  • 45. • Subdural recording showing a run of vertex waves and widely distributed K-complexes, maximally expressed in the parietal lobe during arousal. • Harmonic of the sleep spindles is frequently seen in intracranial EEGs. • In addition, the sleep spindles usually are sharper in morphology as the scalp and skull act as a high-frequency filter and pass lower frequencies more efficiently than higher frequencies. • Disappearance during wakefulness • helps to differentiate the K-complexes from low-voltage fast ctivity. • All normal EEG rhythms in the scalp EEG can be seen in the intracranial EEG. Subdural EEG Monitoring; K-Complex During Arousal
  • 46. Subdural EEG Monitoring; K-Complex During Arousal
  • 47. • The differentiation of physiologic waveforms and pathologic waveforms is extremely important in intracranial EEG recording (open arrow-epileptiform in depth electrode; arrow-sleep spindles; double arrows- vertex waves). • Harmonic and sharp morphology of the physiologic waveforms in an intracranial EEG make distinguishing between onepileptiform and epileptiform activities more difficult. • Disappearance of spindles and vertex waves during wakefulness, distribution, and morphology help to diff erentiate them from epileptiform activity, especially between sleep spindles and low-voltage fast epileptiform activity Pathologic vs Physiologic Wave Forms in Intracranial EEG
  • 48. Pathologic vs Physiologic Wave Forms in Intracranial EEG
  • 49. • K-complex first appears at 4 months of age. • They have high amplitude but their rise is not as abrupt and the configuration isnot as sharp as one seen in older children Early K-Complex (16 Week CA)
  • 51. • Sleep spindles arise from synchronized activity in functionally important neuronal networks linking the thalamus and the cortex. • Spindles result from rhythmic spike bursts in inhibitory (GABAergic) thalamic reticular neurons that induce rhythmic rebound bursting in cortical neurons. This process has been shown to result in effective deafferentiation of the cerebral cortex. • Cortical neurons show enhanced responsiveness and properties of synaptic plasticity that may have a role in memory and learning processes. • At 1.5 to 2 months, 14/sec spindles are first seen Normal Sleep Spindles (2 Months); Definite 14/sec Spindles
  • 52. Normal Sleep Spindles (2 Months); Definite 14/sec Spindles
  • 53. • EEG of an 8-week-old full-term boy shows low-voltage 22–24 Hz biphasic beta activity diffusely in the central vertex and bilateral central-parietal areas. • This exceptional waveform most likely represents a harmonic of sleep spindles. • More commonly spindles occur independently from faster 18–25 Hz activity and both patterns may be seen at the same time Normal Sleep Spindles (8 Weeks CA); Harmonic of Sleep Spindles
  • 54. Normal Sleep Spindles (8 Weeks CA); Harmonic of Sleep Spindles
  • 55. • Trace alternant disappears in the first month of life. • Sleep spindles usually appear in the second months of life with frequency between 12 and 15/sec. Throughout infancy, they are maximal over the central and parietal areas with shifting asymmetry. • They usually are electronegative with a rounded positive component. • A complete absence of spindles at age 3–8 months indicates a severe abnormality Normal Sleep Spindles (10 Weeks CA)
  • 56. Normal Sleep Spindles (10 Weeks CA)
  • 57. • Between the ages of 3–6 months, sleep spindles appear to be biphasic and occur as prolonged runs, up to 10–15 sec. • The prolonged run of spindles is a very useful developmental marker and is rarely seen beyond this age range Normal Sleep Spindles (3-6 Months CA); Prolonged Runs of Spindles
  • 58. Normal Sleep Spindles (3-6 Months CA); Prolonged Runs of Spindles
  • 59. • Between the ages of 3–6 months, sleep spindles appear to be biphasic and occur as prolonged runs, up to 10–15 sec. • The prolonged run of spindles is a very useful developmental marker and is rarely seen beyond this age range Prolonged Sleep Spindles (3-6 Months CA)
  • 60. Prolonged Sleep Spindles (3-6 Months CA)
  • 61. • Between the ages of 3–6 months, sleep spindles appear to be biphasic and occur as prolonged runs, up to 10–15 sec. • The prolonged run of spindles is a very useful developmental marker and rarely seen beyond this age range. Prolonged Sleep Spindles (3-6 Months CA)
  • 62. Prolonged Sleep Spindles (3-6 Months CA)
  • 63. • Between the ages of 3–6 months, sleep spindles appear to be biphasic and as prolonged runs, up to 10–15 sec. • The prolonged run of spindles is a very useful developmental marker and rarely seen beyond this age range. • Throughout infancy, sleep spindles are maximal over the central and parietal areas with shifting asymmetry. • They usually shows electronegative with rounded positive component that is a typical hallmark of sleep spindles in infancy. • These surface-negative spindles with wicket or comb-like shape can be erroneously interpreted as 14/sec positive spikes (below) Normal Sleep Spindles (16 Weeks CA)
  • 64. Normal Sleep Spindles (16 Weeks CA)
  • 65. Sleep Spindles with subharmonic • Subharmonic of sleep spindles with a frequency approximately half that of sleep spindles with a notched appearance can be seen. • The subharmonic has the same reaction and distribution as sleep spindles
  • 66. Sleep Spindles with Subharmonic
  • 67. • Mitten patterns are seen during sleep and consist of a sharply-contoured waveform on the slope of a slow wave of the same polarity that resemble a mitten, with the thumb of the mitten formed by the last wave of a spindle and the hand portion by the slower wave component. • Mittens are a variant of a vertex wave or K-complex and should not be mistaken for a spike-and-wave discharge. • It is best seen in the referential montage and in stage 3 sleep Mitten Pattern
  • 72. • Hypnagogic hypersynchrony is an activity seen in early drowsiness and in arousal from deeper sleep. • It is characterized by bilateral synchronous, high voltage, rhythmic 3-5 Hz activity. • This activity first appears at the age of 2 to 3 months and becomes prominent and continuous at 9 months. • At age 4 years, it becomes shorter in duration and more paroxysmal in appearance • Hypnagogic Hypersynchrony
  • 73. • By age 9 to 11 years, it becomes rare. Although the presence of hypnagogic hypersynchrony at age 12 years is considered abnormal by some authors,21 it may be seen in normal children up to the age of 12-13 years. • The frequency of hypnagogic hypersynchrony is 3-4 Hz at the age of 2-3 months and increases to 4-5 Hz in older children. • This EEG also shows slow eye movement (SEM), maximally seen at F7 and F8, which is also one of the signs of drowsiness. Hypnagogic Hypersynchrony
  • 75. • Nearly continuous hypnagogic hypersynchrony in a 22- month-old infant. • Hypnagogic hypersynchrony appears at approximately 3 months of age and is characterized by monorhythmic, slow generalized activity with the frequency of 3-4 Hz during drowsiness. • It may be seen in olderchildren up to 12-13 years but is rare after 11 years (incidence of only 10%). • The frequency increases to 4-5 Hz in older children Hypnagogic Hypersynchrony
  • 77. • EEG of a 25-month-old boy with asymmetric hypnagogic hypersynchrony with shifting predominance. • The paroxysmal bursts of generalized high-voltage, rhythmically monotonous theta activity superimposed on low-voltage background activity, so-called “hypnagogic hypersynchrony,” is the hallmark of drowsiness in early childhood. • Occasionally, small sharp or spiky discharges may be interspersed between the theta waves. • Asymmetric Hypnagogic Hypersynchrony
  • 78. • These discharges should not be interpreted as epileptiform activity unless they are definitely distinct from background activity and not only occur during drowsiness or at the onset of sleep but also persist into deeper stages of sleep. • Asymmetric hypnagogic hypersynchrony with shifting predominance can be seen and is not considered abnormal Asymmetric Hypnagogic Hypersynchrony
  • 80. Hypnagogic Hypersynchrony • EEG of a 4-year-old boy with hypnagogic hypersynchrony. • The paroxysmal bursts of generalized high-voltage, rhythmically • monotonous theta activity superimposed on low-voltage background activity, so-called “hypnagogic hypersynchrony” is the hallmark of drowsiness in early childhood. • Occasionally, small sharp or spiky discharges may be interspersed between the theta waves. • These discharges should not be interpreted as epileptiform activity unless they are definitely distinct from background activity and not only occur during drowsiness or at the onset of sleep but also persist into deeper stages of sleep
  • 82. Hypnic Myoclonia (HM) (Sleep Starts or Hypnogogic Jerks) • Video-EEG of a 5-year-old boy with well-controlled focal epilepsy shows a burst of high-voltage 3–4 Hz delta activity intermixed with low-amplitude spikes during chin quivering (*). • This EEG pattern is compatible with hypnagogic hypersynchrony associated with HM. • This wake-to-sleep transition event is characterized by a sudden, single, brief muscular contraction of the legs and occasionally the arms, head, and postural muscles. • Hypnagogic hallucinations often occur before the sleep starts, and the perception of falling may occur, ending with the myoclonic jerk. • HM is a physiologic fi nding unless it is frequent and results in sleep-onset insomnia. It also must be diff erentiated from seizure, especially if it occurs in patients with known epilepsy.
  • 83. Hypnic Myoclonia (HM) (Sleep Starts or Hypnogogic Jerks) • HM occurs in 60–79% of normal individuals. • Ninety percent of patients stop these movements by age 4 years. • It is more common in boys than in girls by 4:1. • It may be frightening when observed by a parent, • especially if associated with a vocalization or cry. • Injury from the massive movement is rare, but foot injuries secondary to kicking a bedpost or crib rail may occur
  • 84. Hypnic Myoclonia (HM) (Sleep Starts or Hypnogogic Jerks)
  • 85. • EEG of a 5-year-old asymptomatic boy shows 14- and 6 Hz positive spikes (arrow head) immediately after hypnagogic hypersynchrony (open arrow). • Fourteen and six hertz positive spikes (arrow head) are commonly seen during drowsiness. 14-and-6-Hertz Positive Spikes; Hypnagogic Hypersynchrony
  • 86. 14-and-6-Hertz Positive Spikes; Hypnagogic Hypersynchrony
  • 87. • An 8-year-old boy with recurrent syncope without other associated symptoms suspicious of seizures or other neurologic conditions except borderline ADHD. • There was a history of GTCS in his 4-year-old brother. • EEG during drowsiness shows hypnagogic hypersynchrony and bilateral-independent centro- temporal spikes. Characteristic spikes over the rolandic area are regarded as neurobiological markers of BECTS. • However, rolandic (centro-temporal) spikes have been reported in normal children without clinical seizures or neurologic manifestations. Asymptomatic Centro-Temporal Spikes; Hypnagogic Hypersynchrony
  • 88. • They are seen in 1.2–3.5% of normal healthy children in the community36,37 and 6–34% of siblings of patients aff ected by BECTS • The risk of epilepsy is higher if rolandic spikes remain unilateral during sleep, rolandic spikes continue during REM sleep, and if they occur in the presence of generalized spike-wave discharges. • The frequency of rolandic spikes in children with ADHD (3–5.6%) is significantly higher than expected from epidemiologic studies although how ADHD symptoms are related to rolandic spikes is still unclear Asymptomatic Centro-Temporal Spikes; Hypnagogic Hypersynchrony
  • 89. Asymptomatic Centro-Temporal Spikes; Hypnagogic Hypersynchrony
  • 90. • Video-EEG of a 5-year-old boy with well-controlled focal epilepsy shows a burst of high-voltage 4 Hz delta activity intermixed with low-amplitude spike-like during right arm jerks (arrow). • This EEG pattern is compatible with hypnagogic hypersynchrony and the right arm jerking is most likely to be hypnic myoclonia. • Sleep starts (hypnic myoclonia) also have been termed “hypnagogic jerks”. • This wake-to-sleep transition event is characterized by a sudden, single, brief muscular contraction of the legs and occasionally the arms, head, and postural muscles. • Sensory hallucinations (hypnagogic hallucinations) often occur before the sleep start, and the subjective perception of falling may occur, ending with the myoclonic jerk. Hypnic Myoclonia; Hypnagogic Hypersynchrony.
  • 91. • Sleep starts are common, occur in most individuals, and are not pathologic unless they are frequent and result in sleep- onset insomnia. • They also must be differentiated from seizure, especially if they occur in patients with known epilepsy. • Hypnic myoclonia occurs in 60–79% of normal individuals. • Although it may occur at any age, 90% of patients stop these movements by age 4 years. • They are more common in boys than girls by 4:1. • It may be frightening when observed by a parent, especially if associated with a vocalization or cry. • Injury from the massive movement is rare, but foot injuries secondary to kicking a bedpost or crib rail may occur Hypnic Myoclonia; Hypnagogic Hypersynchrony.
  • 92. Hypnic Myoclonia; Hypnagogic Hypersynchrony.
  • 93. • Focal rhythm over the midline region, most prominent over vertex with occasional spread to adjacent electrodes • Usually 5-7 Hz, monorhythmic, waxes and wanes • Seen in wakefulness and drowsiness- has variable reactivity • Occurs in a heterogeneous group of patients • May be more common in frontal lobe epilepsy if pathologic Midline theta
  • 96. • Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions during arousal from sleep in children. • The FAR is characterized by 30–150 μV, predominantly monophasic negative waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec) with a characteristic notching of the ascending or descending phase of each wave. • The notched appearance may represent harmonics of the waveforms. • The waxing and waning of the amplitude often leads to a spindle-like morphology. • The FAR appears at the F3 and F4 electrodes with minimal spread to nearby scalp areas.46 The incidence of the FAR in a normal population is unknown. • Although it was first reported in children with minimal cerebral dysfunction or a seizure disorder, it is later considered to be a non specifi c EEG pattern of no clinical significance Frontal Arousal Rhythm (FAR)
  • 98. • EEG of an 8-year-old girl with idiopathic generalized epilepsy. • Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions during arousal from sleep in children between ages 2 and 12 years, mainly 2 and 4 years. • The FAR is characterized by 30–150 μV predominantly monophasic negative waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec), maximally over the frontal midline, with a characteristic notching of the ascending or descending phase of each wave. • The notched appearance may represent harmonics of the waveforms. Waxing and waning of the amplitude often leads to a spindle-like morphology. The FAR appears at the F3 and F4 electrodes with minimal spread to nearby scalp areas. • The incidence of the FAR in the normal population is unknown. • Although it was first reported in children with minimal cerebral dysfunction or a seizure disorder, it is now considered to be a nonspecific EEG pattern of no clinical significance Frontal Arousal Rhythm (FAR)
  • 100. • An 8-year-old girl with a history of GTCS. EEG demonstrates trains of rhythmic 6-Hz sharp waves in bifrontal regions during arousal state. • Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions during arousal from sleep in children. • The FAR is characterized by 30–150 μV, predominantly monophasic negative waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec) with a characteristic notching of the ascending or descending phase of each wave. • The notched appearance may represent harmonics of the waveforms. The waxing and waning of the amplitude often leads to a spindle-like morphology. • The FAR appears at the F 3 and F 4 electrodes with minimal spread to nearby scalp areas.46 The incidence of the FAR in a normal population is unknown. • Although it was first reported in children with minimal cerebral dysfunction or a seizure disorder, it is now considered to be a nonspecific EEG pattern of no clinical significance Frontal Arousal Rhythm (FAR)
  • 102. • EEG of a 10-year-old boy with idiopathic generalized epilepsy. • Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions during arousal from sleep in children between ages 2 and 12 years, mainly 2 and 4 years. • The FAR is characterized by 30–150 μV predominantly monophasic negative waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec), maximally over the frontal midline, with a characteristic notching of the ascending or descending phase of each wave. • The notched appearance may represent harmonics of the waveforms. • Waxing and waning of the amplitude often leads to a spindle-like morphology. • The FAR appears at the F3 and F4 electrodes with minimal spread to nearby scalp areas. • The incidence of the FAR in a normal population is unknown. • Although it was first reported in children with minimal cerebral dysfunction or a seizure disorder, it is now considered to be a nonspecific EEG pattern of no clinical significance Frontal Arousal Rhythm (FAR)
  • 104. • EEG of a 6-year-old boy with frontal lobe epilepsy during arousal from sleep. • Frontal arousal rhythm (FAR) is a rare EEG rhythm, seen in the frontal regions during arousal from sleep in children between ages 2 and 12 years, mainly 2 and 4 years. • The FAR is characterized by 30–150 μV predominantly monophasic negative waves, occurring in bursts or runs lasting up to 13 sec (usually 1–5 sec), maximally over the frontal midline, with a characteristic notching of the ascending or descending phase of each wave. • The notched appearance may represent harmonics of the waveforms. • Waxing and waning of the amplitude often leads to a spindle- like morphology. Frontal Arousal Rhythm (FAR)
  • 105. • The FAR appears at the F3 and F4 electrodes with minimal spread to nearby scalp areas. • The incidence of the FAR in a normal population is unknown. Although it was first reported in children with minimal cerebral dysfunction or a seizure disorder, it is now considered to be a nonspecific EEG pattern of no clinical significance. • Its mildly abnormal character is likely, but its clinical significance was thought to be debatable • Hughes found 70% of patients having epileptic seizures and demonstrated a case in which FAR representing ictal electrographic seizure activity Frontal Arousal Rhythm (FAR)
  • 107. • RTTD is seen in 0.5–2.0% of normal adult population and less common in adolescence. • It is described as bursts or runs of rhythmic, 5–7 Hz (typically 5–5.5 Hz), theta activity with flat-topped, sharply contoured, often notched appearance in the temporal regions, maximally expressed in the mid anterior temporal electrode. • The sharper component of the wave usually has a negative polarity in the anterior temporal region. • It can occur unilaterally, bilaterally, or shifting from side to side with gradual onset and off set. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD); Rhythmic Mid temporal Discharges (RMTD); (Psychomotor Variant)
  • 108. • The pattern is distinguished from ictal epileptiform activity because it is monomorphic and mono rhythmic (no evolution into other frequencies), does not alter background activity, occurs in relaxed wakefulness and drowsiness (most common), and disappears in deeper levels of sleep. • This pattern has no clinical significance. • However, it was considered by some authors to be a pathologic finding in selected cases. • This pattern was previously called “psychomotor variant. • They are also now called “rhythmic mid temporal discharges (RMTDs) Rhythmic Temporal Theta Bursts of Drowsiness (RTTD); Rhythmic Mid temporal Discharges (RMTD); (Psychomotor Variant)
  • 109. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD); Rhythmic Mid temporal Discharges (RMTD); (Psychomotor Variant)
  • 110. • A 15-year-old girl with recurrent passing out episodes. • EEG during drowsiness shows rhythmic 5-6 Hz, theta activity with flat-topped, sharply contoured over the temporal regions with a phase reversal in the posterior temporal electrodes. • Rhythmic temporal theta waves of drowsiness (RTTD) is also called rhythmic mid temporal discharges (RMTDs) or psychomotor variant. • RTTD is seen in adult and, less commonly, in adolescent. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 111. • This EEG pattern is distinguished from ictal epileptiform activity in that it is monomorphic and mono rhythmic (no evolution), does not affect background activity, and occurs in only in relaxed wakefulness and drowsiness. • This EEG pattern is of uncertain significant Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 112. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 113. • A 16-year-old girl with recurrent vertigo who had been diagnosed with simple partial seizures and was treated with carbamazepine. • The treatment failed to stop the symptoms and caused side effects. • Brain MRI was unremarkable. • EEGs were performed four times in the past and were interpreted as epileptiform activity in the temporal regions. • This EEG during drowsiness shows a burst of rhythmical 5.5 Hz theta activity in the left temporal region (open arrow) with negative polarity of the sharper component of the burst in the midtemporal region. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 114. • Note no disruption of alpha rhythm in the left occipital region (arrow heads). • The patient was completely normal throughout the discharge. • This EEG pattern is compatible with RTTD and is considered a normal variant and has no clinical significance. • The patient has done well since stopping carbamazepine Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 115. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 116. • A 17-year-old boy with recurrent headache and numbness of his right arm. • EEG during resting wakefulness shows bilateral- independent 5.5 Hz theta activity in the temporal regions in the 2 hemispheres. • As the discharge proceeds, the morphology does not change (monomorphic and monorhythmic). • The discharge continues during drowsiness but disappears in stage 2 sleep. • These differentiate the RTTD from focal ictal activity Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 117. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 118. • A 17-year-old boy with a new-onset GTCS. • EEG during drowsiness shows runs of bilateral-independent 5.5 Hz sharply-contoured theta activity in the midtemporal regions in the two hemispheres. • As the discharge proceeds, the morphology does not change (monomorphic and monorhythmic). • The discharge continues during drowsiness but disappears in stage 2 sleep. • These findings differentiate the RTTD from focal ictal activity. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 119. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 120. • EEG during drowsiness shows long runs of monomorphic and monorhythmic notched theta activity that does not evolve into other frequencies or waveforms. • The patient was completely normal throughout the run of discharge. • The discharge disappears during deeper states of sleep. • These findings differentiate RTTD from an electrographic seizure. • Note an unusual morphology of the discharge that shows positive polarity in the posterior temporal areas. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 121. Rhythmic Temporal Theta Bursts of Drowsiness (RTTD)
  • 122. • This EEG pattern is defined as bursts of arch shaped waves at 13–17 Hz and/or 5–7 Hz, most commonly at 14 and/or 6 Hz, seen generally over the posterior temporal and adjacent areas of one or both sides of the head during deep drowsiness and very light sleep. • The sharp peaks of its components are electropositive compared to other regions. The bursts have a widespread field and last for 0.5–1 sec. • This EEG pattern occurs in children from the age of 3 up to young adulthood but more commonly occur between 12 and 20 years with a peak at age 13–14 years. It is best displayed in the contralateral ear reference montage. • 14 and 6/sec positive spike discharge is a benign variant of no clinical significance 14 and 6/sec Positive Spike Discharge
  • 123. 14 and 6/sec Positive Spike Discharge
  • 124. • Fourteen and six per second positive spike discharge shows mainly 13 Hz positive spikes 14 and 6/sec Positive Spike Discharge
  • 125. 14 and 6/sec Positive Spike Discharge
  • 126. 14 and 6/sec Positive Spike Discharges; (Anterior-Posterior Bipolar) • This EEG pattern is defined as bursts of arch shaped waves at 13–17 Hz and/or 5–7 Hz, most commonly at 14 and/or 6 Hz, seen generally over the posterior temporal and adjacent areas of one or both sides of the head during deep drowsiness and very light sleep (arrow). • The sharp peaks of its components are positive with respect to other regions. • This pattern occurs in the children after age 3 to young adult with a peak at age 13–14 years. • This pattern is a benign variant of no clinical significance
  • 127. 14 and 6/sec Positive Spike Discharges; (Anterior-Posterior Bipolar)
  • 128. 14 and 6/sec Positive Spike Discharges; (Contralateral Ear Reference) • The 14 and 6/sec positive spike discharges are best seen during a contralateral ear reference run
  • 129. 14 and 6/sec Positive Spike Discharges; (Contralateral Ear Reference)
  • 130. • A 12-year-old boy with symptomatic Lennox-Gastaut syndrome after the treatment of status epilepticus with intravenous midazolam. • EEG showed continuously diff use polymorphic delta activity with superimposed “14-and-6-Hertz positive spikes.” • Although 14- and 6 Hz positive spikes in diff use encephalopathy EEG pattern was once thought to be seen exclusively in coma due to Reye’s syndrome • in other encephalopathies of childhood as well suggesting that they are epiphenomena or a resilient normal. • The 14- and 6 Hz positive spikes are best seen in contralateral ear reference montage. 14-and-6-Hertz Positive Spikes; Diffuse Encephalopathy
  • 132. • With contralateral ear reference, 14- and 6 Hz positive spikes (arrow head) are diffusely seen over both hemispheres but maximal in the right posterior temporal region. • The opposite polarity in the EEG electrodes over the left hemisphere may be suggestive of the dipole character of this waveform 14-and 6-Hz Positive Spikes
  • 134. • Diff use 14 and 6/sec positive spike discharges with right hemispheric predominance during referential run in a 12- year-old adolescent girl with non epileptic events 14 and 6/sec Positive Spike Discharge; Referential Montage
  • 135. 14 and 6/sec Positive Spike Discharge; Referential Montage
  • 136. • When a 14 and 6/sec positive spike discharge is intermixed with diff use delta or theta slowing, it can simulate spike-wave or poly spike-wave activity 14 and 6/sec Positive Spike Discharge; Poly spike-Wave-Like Discharge
  • 137. 14 and 6/sec Positive Spike Discharge; Poly spike-Wave-Like Discharge
  • 138. • Fourteen and six hertz positive spikes (**) can be mixed with sleep spindles (*). • These 2 waveforms can be differentiated from each other by configuration and distribution. • Fourteen and six hertz positive spikes occur predominantly during drowsiness and light sleep and consist of short trains of arch-shaped waveforms with alternating positive spiky components and a negative, smooth, rounded waveform. • a 14 and 6/sec positive spike maximal amplitude over the posterior temporal region. • Sleep spindles occur predominantly during stage 2 sleep and consist of trains of sinusoidal waveforms. • It usually has maximal amplitude over the fronto-central region 14-and-6-Hertz Positive Spikes
  • 140. • During a subdural EEG recording in the patient with right neocortical temporal lobe epilepsy, 14 and 6/sec positive spikes are noted in the right anterior temporal region (open arrow) outside of the epileptogenic zone (blue). • This is an uncommon location of this EEG pattern that is usually seen in the posterior temporal region. • This may be due to brain plasticity. • The patient has been seizure free since the epileptogenic zone, excluding the area containing 14 and 6/sec positive spike discharge, was resected. • This strongly supports the benign nature of this EEG pattern. • The 14 and 6/sec positive spikes EEG pattern has never been reported in the literature. 14-and 6-Hertz Positive Spikes (Subdural EEG Monitoring)
  • 141. 14-and 6-Hertz Positive Spikes (Subdural EEG Monitoring)
  • 142. • Small sharp spike (SSS) is a benign EEG pattern that is seen in 20–25% of a normal adult population. • SSS are seen in adults during drowsiness or light sleep. • They are usually low voltage, short duration, single monophasic or biphasic spike with an abrupt ascending limb and a steep descending limb. • The prominent after coming slow wave may not occur. • SSS occur unilaterally or bilaterally Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS
  • 143. Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS
  • 144. • A 16-year-old girl with a history of migraine who presented with recurrent passing out episodes. EEG obtained during light non-REM sleep shows low voltage, short duration, biphasic spikes with an abrupt ascending limb and a steep descending limb. • The negative and positive components are of approximately equally spiky character. • The spikes are widely distributed in both hemispheres (*). • Small sharp spikes (SSS) or BETS occur almost exclusively during drowsiness or light non-REM sleep. Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS)
  • 145. • A prevalence of 1.36% was found in adult with a peak between ages 30 and 40. • It is uncommonly seen in adolescents. • There is a debate whether this is a normal or an epileptogenic pattern. • In nonepileptics, these discharges may be seen in stroke, syncopal attacks, and psychiatric patients Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS)
  • 146. Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS)
  • 147. • A 17-year-old-right-handed girl with recurrent episodes of deja vu. The presurgical work-up was consistent with right mesio-temporal epilepsy. • EEG shows frequent small sharp spikes (SSS) during drowsiness and light sleep (arrow head). • The patient has been seizure free since the right anterior temporal lobectomy. • “Small sharp spikes (SSS)” is a benign EEG pattern that is seen in 20–25% of • a normal adult population. Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS); Benign Sporadic Sleep Spikes (BSSS)
  • 148. • SSS are seen in adults during drowsiness or light sleep, usually low voltage (less than 50 μV), short duration, single monophasic or biphasic spikes with an abrupt ascending limb and a steep descending limb. • The prominent after coming slow wave may not occur. • SSS are almost always bilaterally represented, either ccurring independently or having reflection to the opposite hemisphere. • The bilateral occurrence of the SSS should not be misinterpreted as bilateral epileptogenic foc Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS); Benign Sporadic Sleep Spikes (BSSS)
  • 149. Small Sharp Spikes (SSS); Benign Epileptiform Transients of Sleep (BETS); Benign Sporadic Sleep Spikes (BSSS)
  • 150. • A 9-year-old girl with right mesio-temporal epilepsy caused by mild MCD. • She has been seizure free since the left temporal lobectomy. EEG during drowsiness shows diff use SSS, predominantly in the left hemisphere. • “Small sharp spikes (SSS)” is a benign EEG pattern that is seen in 20–25% of a normal adult population. • SSS are seen in adults during drowsiness or light sleep, usually low voltage, short duration, single monophasic or biphasic spikes with an abrupt ascending limb and a steep descending limb. The prominent after coming slow wave may not occur. SSS occur unilaterally or bilaterally. • Some authors believed this pattern indicates a “moderate degree of epileptogenicity. Small Sharp Spikes (SSS)
  • 152. • This EEG pattern can be seen in 2.5% of both adolescents and young adults. • It occurs during relaxed wakefulness, drowsiness, and light sleep and disappears during deeper stages of sleep. • It is described as bursts of 1–2 sec duration, diff use, low voltage, 5–7 Hz, spike-and-wave discharges, commonly bifrontally or occipitally. • At times, spikes are difficult to see. • This EEG pattern is regarded as a benign variant of uncertain • significance. • Six-hertz spikes with minimal or no associated waves may represent a transitional pattern between 6-Hz spike-wave bursts and 14 and 6 Hz positive bursts. Six-Hertz Spike-and-Wave Bursts; (Phantom Spike- and-Wave Discharge)
  • 153. Six-Hertz Spike-and-Wave Bursts; (Phantom Spike-and- Wave Discharge)
  • 154. • Six-hertz spike and wave bursts in an 11-year-old girl with recurrent syncopal attacks associated with migraine. • Six-hertz spike and wave bursts (arrow) can be very difficult to distinguish from atypical spike-wave activity. • The clue to make a distinction is that benign 6-Hz spike and wave bursts occur during relaxed wakefulness and drowsiness and disappear during deeper stages of sleep. • Two types of 6-Hz-spike-and-wave discharges have been described, FOLD (Female, Occipital, Low amplitude, Drowsiness) and WHAM (Wake, High-amplitude, Anterior, Male). • FOLD is more benign, and WHAM is more likely to be associated with seizures Six-Hertz Spike-and-Wave Bursts
  • 156. • Wicket waves are one of the most common over-read EEG patterns64 seen almost exclusively in adults, most commonly >30 years of age and, usually older than 50 years. • Wicket waves are relatively rare with an incidence of 0.9%. • It occurs in clusters or trains, but also as single sharp transients, of 6- to 11-Hz negative sharp aciform waves with amplitude of 60–200 μV. • They are seen over the anterior or midtemporal regions during relaxed wakefulness but facilitated by drowsiness and may occur in light sleep. • Wicket waves occur unilaterally with a shifting asymmetry between the two hemispheres. • During the waking portion of the record, wicket waves are often • masked by background EEG activity. • Recently, wicket waves have also been reported to occur during REM sleep Wicket Wave
  • 157. • Their cardinal feature is a changing mode of occurrence through any single recording, from intermittent trains of more or less sustained, aciform, discharges resembling mu rhythm, to sporadic single spikes. • Amplitude may be high, but the transient arises out of an ongoing rhythm and does not stand out. • When occurring singly, wicket waves can be mistaken for anterior or mid-temporal spikes. • Isolated wicket wave(s) can be differentiated from epileptiform discharge (s) by the following criteria: • (1) no slow wave component following the wicket wave; • (2) occurring in trains or in isolation • and do not disrupt the background; • (3) having a similar morphology to the waveforms in the train when they occur as a single spike. • Wicket wave is considered a benign variant pattern and is not associated with epilepsy Wicket Wave
  • 159. • A 12-year-old-right-handed boy with medically intractable epilepsy caused by nonaccidental trauma in infancy. • Interictal EEG shows trains of negative sharp arciform waves in the right anterior temporal region (box), continuously low-amplitude polymorphic delta activity (PDA), and suppression of background activity over the right hemisphere, maximal in the temporal region. • The trains of sharp waves are similar to “wicket waves.” • MRI demonstrates multifocal encephalomalacia but maximal over the right anterior temporal region (open arrow). • Wicket waves are most commonly seen in individuals older than 30 years of age. • Wicket waves are relatively rare with a prevalence of 0.9% in adults but unknown in children. • They occur in clusters or trains, but also as single sharp transients, of mid- or anterior temporal 6–11 Hz negative sharp arciform waves with amplitude of up to 200 μV. Wicket-Wave Like Waveform; Non accidental Trauma
  • 160. • Wicket waves can be differentiated from temporal lobe epileptiform discharges based on the following criteria: • (1) no slow wave component following wicket spikes; • (2)occurring intrains or in isolation and do not disrupt the background; • (3) having a similar morphology to the waveforms in the train when they occur as a single spike. • Wicket waves are more commonly seen in patients with cerebrovascular disease. • In this EEG, the age and abnormal background activity are strongly against the diagnosis of wicket waves and supportive of epileptiform activities. Wicket-Wave Like Waveform; Non accidental Trauma
  • 161. Wicket-Wave Like Waveform; Non accidental Trauma
  • 162. • A 4-month-old boy who developed a right-sided focal motor seizure after cardiac surgery for complex congenital heart defects. • MRI with DWI shows cerebral infarction in the left fronto-temporal region. • Interictal EEG shows trains of negative sharp arciform waves in the left posterior temporal region (box) and suppression of background activity over the left hemisphere. • The trains of sharp wave configuration are similar to “wicket waves.” • Wicket waves are most commonly seen in individuals older than 30 years of age. Wicket-Wave Like Waveform; Left Frontal- Temporal Infarction
  • 163. • Wicket waves are relatively rare with a prevalence of 0.9% in adult but unknown in children. • They occur in clusters or trains, but also as single sharp transients, of mid- or anterior temporal 6–11 Hz negative sharp arciform waves with amplitude of up to 200 μV. • Wicket waves can be differentiated from temporal lobe epileptiform discharges based on the following criteria: • (1) no slow wave component following wicket spikes; • (2) occurring in • trains or in isolation and do not disrupt the background; • (3) having a similar morphology to the waveforms in the train when occurs as a single spike. Wicket-Wave Like Waveform; Left Frontal- Temporal Infarction
  • 164. • In this EEG, the age and abnormal background activity are strongly against the diagnosis of wicket waves but supportive of epileptiform activities. • In adult, wicket waves are more common seen in patients with cerebrovascular disease Wicket-Wave Like Waveform; Left Frontal- Temporal Infarction
  • 165. Wicket-Wave Like Waveform; Left Frontal- Temporal Infarction
  • 166. Reference: Atlas of pediatric EEG