semiological classification of seizure, localisation and lateralisation
localisation and lateralisation
Dr. Vinayak Rodge
That branches of linguistics concerned with
signs and symptoms
A sudden neurologic occurrence such as a
stroke or an epileptic seizure
Glossary of 2001 ILAE report
Epilepsia 42(9):1212-8, 2001
Detailed Analysis of Seizure
Seizure - main symptom of epilepsy
Seizure control - target of treatment
Differentiate between epileptic and nonepileptic
1998, Lüders et al.
Semiological seizure classification
2001, ILAE Commission Report
Glossary of descriptive terminology for
Semiological Seizure Classification
Lüders et al. (1998)
Aura features Lateralising and localising value
Visual Flashing light of different colour ,circular, crossing
Contalateral to area 17 and 18,
v illusion- v. association cortex parito-
Auditory Positive-“buzz”, noise : Negative-loss hearing. Heschells gurus in STG, LTLE
Olfactory Unpleasant smells Mesial temporal lobe epilepsy (high %
have amygdala neoplasm)
Gustatory Unpleasant taste insula
Tingling, numbness, unpleasant heat and pain If u/l –c/l prim. Sensory cortex
If b/l-supplementary sensory motor area,
second sensory-motor area(superior
sylvian or posterior to insula)
Subjective sensation of palpitation, sweating,
Abdominal Nausea, tenseness, knot rolling, butterfly .
Mainly localise to epigastriam . Sensation of
increase peristalsis (van buren assesed same with
gastric balloon during aura )
Temporal (mc) frontal ,insula
Psychic Fear, elation ,déjà vu (inappropriate feeling of
familiarity ) ,jamais vu .
No lateralising value , localise to mesial
temporal lobe (right )
“Dialeptic”, old Greek, means “to interrupt, stand
still, or pass out”
Alteration of consciousness
Episodes of unresponsiveness or decreased
Associated with complete or at least partial
amnesia for the episode
• it can be absence seizures (dialeptic seizures with
a generalized ictal EEG) and complex partial seizures
(dialeptic seizures with a focal ictal EEG).
Generalized absence seizures
seizuresuspension of awareness and arrest of activity
•sudden onset without any aura ,
•brief duration, typically less than 15 seconds,
•sudden termination without any postictal state.
•Generalized 2.5 to 4 hz spike and wave activity.
•Slower loss of awareness and more gradual recovery
as well as more prominent motor manifestations.
•Slower frequency less than 2.5 hz
features Absence Complex partial
Frequency Frequent many per day Less frequent
Onset and progression Abrupt and minimal slow
Aura ,automatism None or rare common
Motor signs Rare or minimal common
duration Brief ,<15 sec minutes
Postical confusion None common
Postictal dysphasia none Common if originating from
Hyperventilation Induce the seizure No effect
Sleep activation none common
Objective proof of the autonomic
alteration (i.e., tachycardia documented
by EKG monitoring)
vs Autonomic Aura
Autonimic seizures Lateralising and localising value
Pilomotor seizure- May spread in
jacksonian march (spread unilaterally to
adjacent body part )
Ipsilateral to seizure onset zone. Localisation
Ictal vomiting /retching Temporal (mainly) ,insula
Ictal spitting Right temporal lobe
Ictal hyper salivation Mesial temporal , lateralise to non dominant
Autonomic seizure (must have objective
Must be documented , for example – ictal
tachycardia must be documented with ECG
2 major subgroups
Simple : “Simple”, unnatural
Reproducible by direct stimulation of the
primary motor cortex
Complex : Complexity of movement
Generated by widespread neuronal
matrices, natural but Inappropriate for the
- duration of the muscle contraction
- rhythmicity of movement repetition
- muscles involved
features Lateralising and localising value
Clonic Series of recurrent regular myoclonic
contractions at rate of 0.2-5/sec
Contralateral to primary motor cortex.
In- frontal involve earlier .
Secondary generalisation started on
contralateral side and ends on ipsilateral (“end of
seizure paradoxical clonus” ).
Asymmetric seizure termination rare in prim.
Myoclonic Short muscle contractions lasting <400ms Generalized epilepsy
spasm ( few
sec. to min )
Symmetric Muscle contraction either tonic
or myoclonic predominantly affect trunk
and proximal axial muscles followed by
extension and abduction of the arms in a
“salaam position”. , usually appear in
clusters . ,variable duration .
Mechanism -not been clearly determined
but involvement of the brainstem raphe nuclei
and spinal pathways has been suggested
forced and involuntary turning of the head
and eyes in one direction with neck
extension resulting in a sustained
unnatural position .
Symptomatic zone- frontal eye field.
Versive seizures appear earlier in- frontal lobe
origin than TLE (can be the first sign in FLE ).
Versive seizures – lateralized to contralateral
hemisphere, specially when within 10 seconds
before secondary generalization.
Features Lateralizing and localizing value
Tonic •Sustained muscle contractions >3 s that leads
to tonic posturing
•Tonic contraction of chest and abdominal
muscle- “tonic epileptic cry”
Secondarily generaliztion -
have a typical “motor sequence-
1. The tonic face seizure and the versive
seizure lateralize contralateral side.
2. The fencing position lateralizes
contralateral to the raised arm .
3. The asymmetric tonic limb posturing “sign
of four” lateralizescontralateral to the
Most commonly- frontal lobe epilepsy
(62.2%) mainly bilateral and
rarely temporal lobe epilepsy (1.7%)
(only unilateral tonic seizures ).
if clearly unilateral lateralize to
Tonic clonic •Generalized epilepsy - start with symmetrical
tonic posturing of all the limbs followed by a
“jittery” phase clonic activity of all four
• Focal epilepsies – seconadary generalization
almost always preceded by other seizure types
and the tonic phase is usually asymmetric.
Features Localising and lateralizing value
Hypermotor movements involve more than one articulation and
resemble normal movements mainly the trunk and
proximal segments of the limbs.
Ex. peddling movements, running, etc.
May resembles sexual activity, like violent writhing,
thrusting and rhythmic movements of the pelvis,
arms and legs, picking and rhythmic manipulation of
the groin or genitalia.
Consciousness may be preserved.
Mostly during sleep
Most originate from the orbital or
mesial frontal regions.
may be from temporal lobe and
Automotor Mainly involves distal segments of the hands, feet,
mouth and tongue.
Automotors can be unilateral or bilateral . Unilateral
automotors is likely a manifestation of limb
dystonia in the contralateral limb.
95% are associated with altered consciousness.
Typical of TLE but occasionally
Frontal automotor are shorter .
Unilateral automatisms are more
frequently lateralize to ipsilateral .
Gelastic main motor manifestation is “laughing” .
In 50% of the cases hypothalamic hamartomas were
detected by MRI.
structures are anterior cingulate
region- frontal, parietal and
•Natural ,repetitive coordinated motor activity that is
inappropriate to the situation .
•Automatism are usually associated with altered
sensorium and amnesia.
Oro-alimentary- lip smacking/ licking, chewing,
Manual automatism- involving hand.
manipulative ( imply interaction with nearby objects). and
Pedal automatisms-involving feet.
Hyperkinetic- bicycling, pelvic thrusting.
Dyscrystic -involuntary crying
All seizures are negative or inhibitory motor seizures
except the aphasic seizures that mostly represent negative
Negative myoclonic seizures
Features Localization and
loss of postural tone with falls or head drop.
Most frequently in -symptomatic generalized epilepsies (Lennox-
Gastaut syndrome) and are usually preceded by a generalized,
proximal myoclonic seizure resulting in an abrupt fall.
Generalized. (LGS )
Focal - seen in FLE and TLE.
these are slower falls and
rarely significant injuries.
It consist of epileptic falls.
Most commonly are due to a myoclonic seizure f/ b an atonic . But
it can be due to atonic seizures .
Decrease or total absence of motor activity.
Only used in whom consciousness cannot be tested during or after
the seizure (newborns, infants ,children < 3 yr mentally retarded)
In focal epilepsy- temporal
and parietal lobe epilepsy.
Inability to perform voluntary movements.
The diagnosis only be made in patients who are conscious and
cooperative, i.e. they try to perform a movement but are unable to
do so (apraxia).
motor areas in the mesial
and inferior frontal gyri.
A very brief loss of muscle tone of (<400 ms ) which is appreciated
when the affected extremities are elevated or engaged in other
activity. The movement observed are similar to observed in
U/L lateralise to the post-
cerebral cortex .
Patient is aphasic despite preserved awareness and memory.
Can also present as status epilepticus.
Lateralize to the dominant
(FRONTAL PARIETAL OCCIPITAL)
MESIAL TEMPOTAL/LATERAL TLE
SMA/ MOTOR AREA
MESIAL /LATERAL OLE
U/I limb automatism U/L clonic movement
Early head deviation U/L dystonia
u/l blinking Late head or eye turning
Post ictal nose wiping Ictal akinesis
Asymmetrical termination of clonic jerks
followed by GTCS
Post ictal paresis
Whole body turning
Ictal aphasia Ictal speech
Post ictal dysphasia b/l automatism with preserved
Ictal smile. Spitting, vomiting
Lateralising sign Lateralizing value Symptomatogenic zone
Unilateral dystonic posturing contra lateral Activation of BG , TLE
Hemi field visual aura contra lateral Broadman area 17-19 and
adjacent area of OLE
version contra lateral Broadman area 6 and 8
Ictal aphasia and dysphasia dominant Impairment of language
Automatisms and preserved
Non dominant , Unknown , left or bilateral
Lateralising sign Lateralising value Symptomatogenic zone
Post-ictal palsy 93 % contra lateral Area 4 and 6
Post-ictal nose wiping 92% ipsilateral Unknown , TLE
Figure of 4 sign 89% contra lateral SMA , prefrontal area , TLE,
Unilateral sensory aura 89 % contra lateral Area 1,2,3
Tonic activity 89% contra lateral SMA , also possibility of
broadman area 6, , anterior
cingulate gyrus and
subcortical structures FLE
Lateralising sign Lateralising value Symptomatogenic zone
Ictal speech 83 % non dominant Areas other than those
Clonic activity 83% contra lateral Area 4 and 6 .FLE
Unilateral ictal eye blinking 83% ipsilateral unknown
Ictal vomiting 81 % non dominant Medial ,lateral superior and
inferior structure of non
dominant temporal lobe and
Ictal spitting 76 % non dominant Possible asymmetry of CAN
Generalized epileptic seizures
These are conceptualized as
originating at some point
within, and rapidly
distributed networks. …can
include cortical and
subcortical structures, but
not necessarily include the
Frontal lobe seizures
•Sudden onset and offset
•Short duaration <2min ,frequent .
•Early motor signs ,Dystonic posturing
•Bimanual –bipedal automatism
•Little or no postictal cofusion
•Multiple in single night
•No wandering/ complex directed behavior
localisation Semiological features
Primary motor cortex Clonic seizure with or without jacksonian march and todd’s palsy,
cortical myoclonus, consciousness preserved
Complex bizarre automatism ,forced acting is common
Asymmetrical tonic seizures, well known ‘fencing posture’ I/L
arm flex and C/L extended (figure of ‘4’) , short duration ,occur in
cluster frequently arise out of sleep .ictal vocalisation
Mesial frontal hyperkinetic motor behaviour, ictal expression (emotions)
Frontal eye field (+/-
Eye and head deviation ,ictal vocalisation or speech arrest (with
Hyperkinetic automatism with agitation , duration-short post-
ictal –brief or nonexistent ,risk of misdiagnosis as psychogenic
Rolandic or Frontal
Facial clonic movement ,swallowing hyper salivation, speech
Non localising Rare ,staring spell, difficult to distinguish frontal absence
Autosomal dominant ,During sleep ,Like parasomnia –jerky ,
dystonic posturing ,bending rocking
•Hypersalivation is very common
•Autonomic –retching palpitations
TEMPORAL LOBE EPILEPSY
AURA- Common ( epigastric )
DURATION- 1-2 min and more
FREQUENCY- Few per month
ONSET- slow behavioural arrest, and stare
AUTOMATISM- Simple oro-alimentary
VOCALISATION- Simple speech
POSTICTAL- Confusion , aphasia up to minutes
Differences medial and lateral TLE
MTLE ( aura, arrest,
Epigastric aura (MC) ,olfactory ,psychic
Auditory, cephalic (vertiginous illusion )
,experimental , complex aura
Motionless stare (behr arrest ) Anxious ,agitated behaviour
Speech arrest in dominant Vocalization
Early oro-alimetary and hand automatism Early complex automatism (gross truncal)
I/L limb automatism and C/L dystonic
Less automatism, no dystonia.
Less sec. generalization Frequent sec. generalisation
Limbic aura Aura (Area specific)
Hypomotor activity , stare motionless
arrest ( behr arrest )
Complex motor movement Primary motor movement
Dystonic posturing Tonic posturing
Slow evaluation Fast evolution
>1 min. duration brief
Temporal plus /pseudotemporal
Early motor features (version, eye deviation)
ET aura –sensory and throat sensation
No antecedent event
High frequency ,clustering
Clinical characteristics of temporal
and frontal CPS
CLINICAL TEMPORAL FRONTAL
AURA Common, epigastric Vague, nonspecific
DURATION 1-2 min Brief 10-60 sec
FREQUENCY Few per month Several per week
ONSET Slow behavioural arrest, and stare
Abrupt forceful movement,
frequent sleep activation
AUTOMATISM Simple oro-alimentary Complex bipedal bizarre
SPEECH Simple verbalization speech in non
Complex ,loud vocalization
(grunting ,screaming )
GENERALISATION Uncommon Common
POSTICTAL Confusion , aphasia up to minutes Absent or minimal
Parietal lobe epilepsy
•Next most likely source of seizure after TLE and FLE
•Best recognized manifestation is -sensory aura –
numbness, tingling, pins and needles, burning pain.
•With sensory march- post central primary sensory
•Without sensory march- second sensory area
(parietal operculum )
•Seizures without parietal lobe symptoms- most of
have no parietal symptoms but rather manifestation
resulting from spread to occipital ,temporal, or frontal.
Occipital lobe epilepsy
cardinal symptom (20-70 %)
brief, multicloured and circular
may be only manifestation
postictal headache (nonspecific -TLE)
MOTOR SYMPTOMS –
•b/l blinking, nystagmoid eye movements, eye deviation (c/l)
•One distinctive feature –it develop and propogate posteriorly
very slowly (Eye deviation seen in OLE is much slower than in
FLE and TLE )
Dacrystic- quiritarian (crying)
Post temporal –with tears sometimes
Frontal- unnatural ,forced
Rare report of seizure
•Seen is cerebellar ganglioglioma
•Characterizes by hemifacial twitching ipsilateral to
lesion and at same times contralateral head and eye
deviation or contralateral nystagmus.
Clinical approach to patient with
Age of seizure onset-(neonatal ,childhood, juvenile,
Warning symptoms -Aura (abdominal, sensory,
visual, no aura )
What happens during seizures -(awareness,
automatism, incontinence/tongue bite )
Post-ictal period- (confusion, aphasia, preserved
speech, paralysis , immediate recovery-no confusion )
Diurnal variation (early morning/ after awakening,
any time, during sleep )