EEG - NORMAL & ABNORMAL IN NEONATAL INFANTS AND CHILDREN - DR.CHAKRADHAR MADDELA NEONATOLOGIST

2. EVOLUTIONARY CHANGES OF EEG DURING
INFANCY & EEG PATTERNS IN CHILDREN

3. The EEG features should be read under
following categories

4. EEG FEATURES FOR INTERPRETATION

5. CONCEPTUAL AGE GROUPS FOR EEG
INTERPRETATION

7. NEONATAL CONCEPTUAL AGE (CA) EEG INTERPRETATION –
BACKGROUND ACTIVITY 38 – 44 weeks
 Awake – continuous liw voltage activity – mixed type.
 Quite Sleep – trace alternans which disappears CA 46
weeks.
 Active Sleep – continuous activity – low voltage &
irregular.

8. NEONATAL CA EEG INTERPRETATION – SYNCHRONY
 24 – 26 wks: Synchronous EEG activity +++
 27 - 28 wks: not seen much.
 30 – 32 wks: may or may not be noticed +/-

9. NEONATAL CA EEG INTERPRETATION – SYNCHRONY
 33 – 34 wks: synchrony noticeable but absent during quite
sleep.
 35 – 37 wks: synchronous EEG +++, may be absent during
quite sleep.
 38 – 44 wks: synchronous EEG.

10. NEONATAL CA EEG INTERPRETATION – TRANSIENTS
 24 – 26 weeks: Sharp theta waves on the occipital areas
of premature infants (STOPS).
 27 – 29 weeks: Premature temporal theta activity
(PTT), diffuse delta brush activity (DB), slow activity in
occipital areas.
 30 – 32 weeks: Predominantly delta activity in occipital
area & alpha bursts in temporal areas.

11. NEONATAL CA EEG INTERPRETATION – TRANSIENTS
 33 – 34 weeks: Rolandic & occipital delta brush activity,
temporal alpha bursts activity.
 35 – 37 weeks: Frontal sharp transients (FST), bifrontal
delta activity (BFD).
 38 – 44 weeks: Predominantly FST & BFD activities and
temporal sharp transients.

12. NEONATAL CA EEG INTERPRETATION – SLEEP – WAKE CYCLE
(SWC)
 24 – 29 weeks: Sleep wake cycle is absent.
 30 – 32 weeks: Poor SWC
 33 – 34 weeks: SWC dominently seen during active sleep
and also in quite sleep.
 35 – 37 weeks: SWC seen during awake, quite and active
sleep.
 38 – 44 weeks: SWC is mature.

13. NEONATAL CA EEG INTERPRETATION – REACTIVITY
 EEG changes to reactivity may appear after 33 weeks CA.
 35 – 44 weeks: EEG changes to reactivity is certainly
noticeable in this sge group.

14. EEG CHANGES AFTER NEONATAL PERIOD
 Infancy: Delta to theta shift
 >2 years: Delta activity declines.
 3 years: Predominantly theta waves with some delta
waves.
 3 – 6 years: Declined diffuse theta activity.
 8 years: Some theta activity persists.
 CAUSE OF CONCERN (CEREBRAL DYSFUNCTION)
 -predominant delta activity after 4 or 5 years
 - asymmetric slowing.

15. AWAKE EEG IN CHILDREN – POSTERIOR DOMINANT RHYTHM
(PDR)
 At birth – PDR absent
 3 – 4 months: PDR appears at a frequency of 3 – 4 Hz.
 6 months: PDR is 5 Hz
 1 year: PDR is 6 Hz
 2 year: PDR is 7 Hz
 3 year: PDR is 8 Hz.

16. SLEEP EEG
 TERM INFANT:- IN QUIET SLEEP – TRANSITION FROM TRACE
ALTERNANS TO CONTINUOUS HIGH VOLTAGE SLOW ACTIVITY.
 2 MONTHS - SLEEP PATTERN DEVELOPS BUT IMMATURE.
 2 YEARS – SLEEP PATTERN IS MATURE WITH SYNCHRONOUS SLEEP
SPINDLES DURING STAGE 2 SLEEP.
 CAUSE OF CONCERN – UNILATERAL ABSENCE OR ASYNCHRONOUS
SLEEP SPINDLES BY 2 YEARS IS ABNORMAL (CEREBRAL
DYSFUNCTION).
 K – COMPLEXES & VERTEX WAVES SEEN BY 5 – 6 MONTHS (especially
in stage 2 sleep )
 NON-REM SLEEP SEEN BY 3 MONTHS
 REM SLEEP DECLINES AS AGE ADVANCES.
 REM SLEEP – 50% IN FULL TERM INFANTS, 40% BY 3 MONTHS & 20%
IN ADHOLESCENTS & ADULTS.

17. EEG VARIANTS IN CHILDREN
 HALF ALPHA VARIANT : THESE WAVES WITH NOTCHED
APPEARANCE SEEN IN CHILDREN ABOVE 8 YEARS AS PDR.
 POSTERIOR SLOW WAVES OF YOUTH : SEEN BETWEEN 2 –
21 YEARS OF AGE IN DELTA RANGE. IT IS ATTENUATED BY
EYE OPENING AND ALERTNESS.
 HYPNOGOGIC / HYPNOPOMPIC HYPERSYNCHONY: SEEN
BETWEEN 6 MONTHS TO 2 YEARS WITH HIGH VOLTAGE,
DIFFUSE BURST SUPPRESSION (>35mV).

18. ABNORMAL EEG PATTERNS IN NEONATES
 IN NEONATES :
 1. BFNE – BENIGN FAMILIAL NEONATAL EPILEPSY. EEG SHOWS THETA
SHARP WAVE PATTERN WITH MULTIFOCAL SPIKES.
 2. NME – NEONATAL MYOCLONIC ENCEPHALOPATHY. SEEN BETWEEN
BIRTH TO EARLY INFANCY. EEG SHOWS BURST SUPPRESSION
PATTERN WITH MYOCLONUS, PERIODS OF DISMATURITY AND
COMPLEX BURSTS AND SHARP WAVES.
 3. OHTAHARA SYNDROME – SEEN BETWEEN BIRTH TO EARLY INFANCY
WITH BURST SUPPRESSION PATTERN ON EEG.

19. NEONATAL SEIZURES
 ALL NEONATAL SEIZURES DO NOT FIT INTO A SINGLE EEG PATTERN.
 NEONATAL CLINICAL SEIZURES MAY PRESENT WITH OR WITHOUT
ELECTROGRAPHIC SEIZURES.
 NEONATAL SEIZURES WITH BURST SUPPRESSION PATTERN, LOW
VOLTAGE PATTERN AND VERY LOW VOLTAGE OR FLAT TRACE ARE
ASSOCIATED WITH POOR NEURODEVELOPMENTAL OUTCOME.
 DURATION OF INTERBURST INTERVAL IS CORRELATED WITH
GESTATIONAL AGE.

20. ABNORMAL EEG PATTERNS IN INFANCY
 IN INFANCY:
 1.EPILEPSY OF INFANCY WITH MIGRATING FOCAL SEIZURES (6MONTHS) –
SEIZURES WITH MULTIFOCAL ELECTROGRAPHIC PATTERN.
 2.WEST SYNDROME – SEEN BETWEEN 3 – 12 MONTHS. DIFFUSE SLOW / SHARP
WAVES WITH ELECTRO DECREMENT AND HYPSARRHYTHMIC BACKGROUND.
 3.MYOCLONIC EPILEPSY OF INFANCY (MEI) – SEEN BETWEEN 6 MONTHS TO 2
YEARS, GENERALIZED SPIKE AND POLYSPIKES WITH NORMAL BACKGROUND.
 4.BENINGN INFANTILE EPILEPSY – SEEN BETWEEN 3 TO 10 MONTHS, EEG SHOWS
VERTEX SPIKES DURING SLEEP WITH NORMAL BACKGROUND.
 5.DRAVET SYNDROME – PEAK INCIDENCE AT 6 MONTHS OF AGE BUT SEEN UPTO
2 YEARS. EEG SHOWS GENERALIZED AND FOCAL SPIKES INTERICTALLY.
 6.NON PROGRESSIVE MYOCLONIC EPILEPSY – SEEN BIRTH TO 5 YEARS WITH
PEAK AT 1 YEAR, SLOW BACKGROUND WITH MULTIFOCAL CONTINUOUS SPIKES,
SHARPS OR SLOW WAVES.

21. ABNORMAL EEG PATTERNS IN INFANCY
 DRAVET SYNDROME:
 CLINICALLY PRESENTS WITH FEBRILE STATUS EPILEPTICUS DURING
INFANCY.
 GENERALIZED TONIC CLONIC SEIZURES OR HEMICONVULSIVE PATTERN.
 HEAD IS SENSITIVE TO RISE IN TEMPERATURE AND MAY LEAD TO
SEIZURES.
 RARE.
 POOR PROGNOSIS – DEVELOPMENTAL REGRESSION.
 INTERICTAL EEG SHOWS – MAY BE NORMAL, GENERALIZED OR FOCAL
SLOWING. GENERALIZED SPIKE OR POLYSPIKE AND WAVE DISCHARGES
OR FOCAL OR MULTIFOCAL DISCHARGES IN FRONTO-TEMPORAL OR
CENTRO-TEMPORAL OR VERTEX AREAS. PHOTOSENSITIVITY IS SEEN IN
ABOUT HALF OF THE PATIENTS.

22. ABNORMAL EEG PATTERNS IN INFANCY
 WEST SYNDROME:
 ALSO CALLED INFANTILE SPASMS.
 TRIAD – 1. MYOCLONIC SEIZURES / TONIC SEIZURES 2.
HYPSARRHYTHMIA AND 3.MENTAL RETARDATION.
 PEAK ONSET BETWEEN 4 TO 7 MONTHS.
 CAN BE SYMPTOMATIC, CRYPTOGENIC OR IDIOPATHIC.
 PROGNOSIS IS GRAVE IN CRYPYOGENIC OR SYMPTOMATIC.
 SEIZURES OCCUR IN CLUSTERS IN TRANSITION FROM SLEEP TO
AWAKENING.
 EEG PATTERN IS CHARECTERISTIC HYPSARRHYTHMIC.
 INTERICTAL EEG: HIGH VOLTAGE MULTIFOCAL SPIKE AND SHARP WAVES
WITH DISORGANISED BACKGROUND.
 ICTAL EEG: HIGH VOLTAGE GENERALIZED SHARP WAVES AND
GENERALISED ELECTRODECREMENT.

23. ABNORMAL EEG PATTERNS IN CHILDREN
 FEBRILE SEIZURES: EEG PATTERN IS NORMAL IN TYPICAL FEBRILE
SEIZURES.
 ALL ATYPICAL FEBRILE SEIZURES (PROLONGED SEIZURES >15
MINUTES, FOCAL ONSET, FAMILY HISTORY OF EPILEPSY, POST-ICTAL
DEPRESSION) SHOULD BE EVALUATED WITH EEG.
ABSENCE SEIZURES / EPILEPSY: AGE OF ONSET IS BETWEEN 6 – 7
YEARS. CHILD EXPERIENCE SUDDEN STOPAGE OF ONGOING ACTIVITY,
BLANK GAZE, EYE FLUTTERING, SHORT DURATION < 30 SECONDS, NO
POST-ICTAL DEPRESSION AND ACTIVATED BY PHOTIC STIMULATION AND
HYPERVENTILATION.
TYPICAL ABSENCE EPILEPSY EEG SHOWS GENERALIZED, SYMMETRIC 3-
Hz SPIKE AND WAVE DISCHARGE WITH LITTLE FASTER FREQUENCY AT
ONSET AND SLOWER FREQUENCY AT TERMINATION.
ATYPICAL ABSENCE SEIZURES (MORE TONE DISTURBANCES, LONGER
DURATION, MENTAL SUB NORMALITY AND OTHER TYPE SEIZURES)
SHOW SLIGHTLY SLOWER AND LOWER FREQUENCY 1.5 TO 2.5 Hz,
ASYMMETRIC AND SLOW BACKGROUND.

24. ABNORMAL EEG PATTERNS IN CHILDREN
 HIHARS (HYPERVENTILATION INDUCED HIGH AMPLITUDE RHYTHMIC
SLOWING ON EEG): IT IS A VARIANT OF ABSENCE SEIZURES WITH
SMILING, YAWNING SND FIDGETING WITH CESSATION OS ACTIVITY,
STARING LOOK AND AUTOMATISMS.
 JUVENILE ABSENCE EPILEPSY: ONSET IS AT PUBERTY. SEIZURES LESS
ARE FREQUENT, OTHER SEIZURAL TYPES MAY BE SEEN LIKE MYOCLONIC
SEIZURES AND GENERALIZED TONOC – CLONIC SEIZURES.
 INTERMITTENT RHYTHMIC DELTA ACTIVITY (IRDA): THIS EEG
PATTERN IS SEEN IN OCCIPITAL REGION IN CHILDREN AND WITH
FRONTAL DISTRIBUTION IN OLDER CHILDREN. SINUSOIDAL, RHYTHMIC
DELTA ACTIVITY WITH LOW AMPLITUDE SPIKES SEEN ON EEG
RECORDING. THIS INTERICTAL EEG PATTERN MAY LATER EVOLVE INTO
3- Hz SPIKE AND WAVE PATTERN.

25. ABNORMAL EEG PATTERNS IN CHILDREN
 JUVENILE MYOCLONIC EPILEPSY: ONSET IS AT PUBERTY. IT
IS AN IMPULSIVE PETIT MAL.
 USUALLY BILATERAL
 MAY INVOLVED A WHOLE LIMB WITH MILD TO MODERATE
INTENSITY. CHILD MAY DROP OBJECTS.
 ACTIVATED BY SLEEP DEPRIVATION.
 MAY PROGRESS TO MYOCLONIC STATUS EPILEPTICUS.
 INTER-ICTAL EEG SHOWS RAPID SPIKE AND WAVE
DISCHARGES WITH 3.5 – 6 Hz, POLYSPIKE AND WAVE
COMPLEXES.
 SLOW WAVES 10 – 16 Hz, PHOTOSENSITIVE AND ABNORMAL
EEG CHANGES DURING SLEEP CAN BE NOTICED.

26. ABNORMAL EEG PATTERNS IN CHILDREN
 BENIGN FOCAL EPILEPSY OF CHILDHOOD / BENIGN
ROLANDIC EPILEPSY:
 ABNORMAL EEG DISCHARGES ARISE FROM CENTRO-
TEMPORAL, OCCIPITAL OR FRONTAL AREAS.
 CENTRO-TEMPORAL LOCATION IS MOST COMMON.
 AGE OF ONSET IS 3 TO 13 YEARS WITH A PEAK AT 9 – 10
YEARS.
 MOST CHILDREN FREE FROM SEIZURES BY 16 YEARS.
 FIFTY PERCENT SEIZURES ARE NOCTURNAL IN ONSET.
 STATUS EPILEPTICUS IS RARE.
 TYPICALLY SEIZURES OCCUR WITH ORO-BUCCAL-LINGUAL
PARESTHESIAS, TONIC OR CLONIC FACIAL MOVEMENTS WITH
SPEECH ARREST, RETENTION OF CONSCIOUSNESS, AND
SIALORRHEA.

27. ABNORMAL EEG PATTERNS IN CHILDREN
 EEG PATTERN SHOWS HIGH AMPLITUDE, DIPHASIC SPIKES / SHARP
WAVES WITH SLOW WAVE ACTIVITY IN MIDTEMPORAL T3 / T4 AND
CENTRAL C3 / C4 AREAS.
 HORIZONTAL DIPOLE WITH SLEEP ACTIVATION OCCURS.
 CHILDHOOD EPILEPSY WITH OCCIPITAL SPIKES - TWO
TYPES OCCUR IN CHILDREN 1. EARLY ONSET (2 – 12 YEARS WITH PEAK
AT 5 YEARS) TYPE SHOWS AUTONOMIC DISTURBANCES AND ALTERED
SENSORIUM. LATE ONSET (3 – 16 YEARS WITH PEAK AT 8 YEARS) TYPE
SHOWS VISUAL SEIZURES AND VISUAL HALLUCINATIONS.
NEUROPSYCHIATRIC MANIFESTATIONS MAY BE SEEN IN BOTH TYPES.
EEG SHOWS HIGH VOLTAGE MULTIFOCAL SPIKE AND SHARP WAVES WITH
DISORGANIZED BACKGROUND ACTIVITY.

28. ABNORMAL EEG PATTERNS IN CHILDREN
 LENNOX-GASTAUT SYNDROME (LGS) INVOLVES SEVERE INTRACTABLE
SEIZURES OCCURING VERY FREQUENTLY IN MENTALLY RETARDED
CHILDREN WITH ONSET BETWEEN 1 – 8 YEARS.
 TONIC SEIZURES ARE MOST COMMON AND ACTIVATED DUTING SLEEP.
 USUALLY RESISTANT TO ROUTINE ANTIEPILEPTIC DRUGS.
 TONIC STATUS EPILEPTICUS CAN BE INDUCED BY BRNZODIAZEPINES.
 EEG SHOWS CHARECTERISTIC 1.5 TO 2.5 Hz SLOW SPIKE AND WAVE
PATTERN WITH SLOW BACKGROUND ACTIVITY.

29. ABNORMAL EEG PATTERNS IN CHILDREN
 DOOSE SYNDROME / MYOTONIC ATONIC EPILEPSY:
 ONSET OF SEIZURES – 7 MONTHS TO <7 YEARS IN A PREVIOUSLY NORMAL
CHILD.
 MYOTONIC-ATONIC SEIZURES INCLUDE VOCALIZATION / GRUNT
FOLLOWED BY ATONIC HEAD OR BODY DROP.
 INTER ICTAL EEG: NORMAL AT EARLY, LATER THETA WAVE ACTIVITY OR
GENERALIZED POLYSPIKE AAND WAVE ACTIVITY.
 ICTAL EEG: GENERALIZED SPIKE, POLYSPIKE AND WAVES.

30. ABNORMAL EEG PATTERNS IN CHILDREN
 JEAVONS SYNDROME / EYELID MYOCLONIA WITH ABSENCE
SEIZURES: EYELID MYOCLONIA WITH UPWARD EYE GAZE
OCCURS IN BRIGHT LIGHT. BUT NOT IN DARK LIGHT. EEG
SHOWS A FREQUENCY OF 4 – 6 Hz PATTERN.
 PHOTOSENSITIVE EPILEPSY: IT IS A REFLEX EPILEPSY WITH
SEIZURES INDUCED BY PHOTIC STIMULATION WITH SPIKE OR
SPIKE AND SLOW WAVE DISCHARGE.
 PSEUDO-LGS SYNDROME: THESE ARE NOCTURNAL FOCAL
SEIZURES / PERIODIC ATONIC SEIZURES / TRANSIENT
ABSENCES. EEG DISCHARGES ARE SLOW AND SLEEP ACTIVATED
WITH REGRESSION OF INTELLIGENCE.

31. ABNORMAL EEG PATTERNS IN CHILDREN
 ACQUIRED EPILEPTIC APHASIA: THIS IS A RARE SYNDROME
INVOLVING LANGUAGE REGRESSION > 4 YEARS AND VERBAL AUDITORY
AGNOSIA, BEHAVIORAL ABNORMALITIES, SEIZURES AND ABNORMAL EEG
PATTERN. EEG SHOWS MUTIFOCAL SPIKE AND SPIKE AND WAVE PATTERN
IN POSTERIOR TEMPORAL REGION WITH SLEEP ACTIVATION.
 ELECTRICAL STATUS EPILEPTICUS OF SLEEP: THIS INVOLVES
ABNORMAL SLEEP ACTIVATED EEG PATTERN WITH OR WITHOUT
PSYCHOMOTOR RETARDATION. EEG SHOWS GENERALIZED SPIKE AND
WAVE PATTERN DURING SLOW WAVE SLEEP.