Page 54 - ILAE_Lectures_2015

Table 2. Classification of neonatal seizures.

(1) adapted from Volpe3

Type Characterisation Ictal EEG abnormalities
Variable
Subtle Ocular, oral-buccal-lingual, autonomic,
apnoea, limb posturing and movements Common

Clonic Repetitive jerking, distinct from jittering. Common if generalised,
Unifocal or multifocal uncommon if focal
Common if focal,
Myoclonic Rapid isolated jerks. uncommon if generalised
Focal, multifocal or generalised
Epileptic origin
Tonic Stiffening. Decerebrate posturing. 
Focal or generalised 
/-
(2) adapted from Mizrahi and Kellaway4,10 

Type Characterisation -
-
Focal clonic Rhythmic muscle contractions

Focal tonic Sustained posturing of limb/trunk

Myoclonic Random single contractions

Spasms Flexor or extensor,  in clusters

Electrographic By definition no clinical correlate

Generalised tonic Sustained symmetric posturing

Motor automatism Ocular, oral-buccal-lingual or progression

movements of limbs

The Mizrahi classification has the advantage that it takes the origin of events into account and
includes clinically silent electrographic seizures. According to the Volpe classification seizures
can be subtle, myoclonic, clonic or tonic. Subtle seizures are the most common seizure type in
both preterm and term babies. Manifestations include:

 Ocular phenomena (staring, blinking, eye deviation, eye opening)
 Oral phenomena (mouthing, chewing, sucking, smiling)
 Autonomic phenomena (change in blood pressure and/or heart rate, pallor, increased

salivation or secretions; central apnoea occurring rarely as the only seizure
manifestation)
 Fragmentary body movements (limb posturing, swimming, pedalling).

Similar phenomena and motor behaviours occur in neonates, especially in premature infants
and encephalopathic infants. Although they are often less stereotyped and may be suppressed
by restraints or triggered by stimulation, these are clinically very difficult to diagnose5.
Prolonged video-EEG has clearly shown that the majority of infants with subtle seizures will
exhibit ictal rhythmic epileptiform activity4,11. The absence of ictal EEG discharges makes an
epileptic origin of these movements less likely. This issue has been addressed in the Mizrahi
classification: motor automatisms without clonic or tonic components and without EEG
correlate are not considered to be of epileptic origin.

Clonic seizures can be focal, multifocal migrating from limb to limb or, rarely, hemiconvulsive.
Jacksonian march is exceptional in neonates, but may be seen in babies with stroke. These
seizures are most likely to be correctly diagnosed clinically12. However, they may be difficult
to differentiate from non-epileptic movements, like jitteriness, tremors or shudders. These non-
epileptic movements can be suppressed by gentle restraint and may be enhanced by sensory
stimuli. There is good correlation with EEG changes.