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contractions become progressively longer and interrupted, resulting in clonic jerking of the
extremities. There may be reflectory emptying of the bladder and bowels, and the patient may
bite their tongue. There are variations on this theme: the tonic or the clonic phase may be
skipped, and asymmetric features (e.g. forced head turn to one side, or asymmetric or
asynchronous jerking) can be seen. After the seizure, the patient is in a deep coma, and it
usually takes 15–60 minutes to regain consciousness. Patients often feel utterly exhausted,
and report diffuse muscle aches, headache, or depressed mood for up to several days after a
generalised tonic-clonic seizure.

Typical absence seizures
This seizure type is characterised by a behavioural and mental arrest for a few seconds. After
the seizure, the patient typically resumes their activity as if nothing had happened. There may
be subtle jerky movements of facial muscles, however the lapse of awareness with immediate
post-ictal recovery is the characteristic feature. The typical absence seizure is seen in
developmentally normal subjects and associated with rhythmic 3 Hz spike and wave
complexes in the EEG.

Atypical absence seizures
These are seen in patients with developmental delay. The behavioural arrest may be longer,
and it may be more difficult to ascertain the arrest as such, compared to the patient’s
behaviour at baseline. The EEG in these patients usually shows background abnormalities
(diffuse slowing), and the spike and wave complexes are of less than 3Hz in frequency.

Absence seizures with special features
Eyelid myoclonia with associated interruption of awareness is the characteristic seizure type
in Jeavon’s syndrome. Myoclonic seizures (discussed below) can also be associated with
momentary loss of awareness.

Myoclonic seizures
These are brief jerks of the extremities and/or axial trunk muscles. A myoclonic jerk
generated in the cortex can be distinguished from subcortically generated movements by its
brief duration (usually less than 50 msec).

Atonic seizures
The ictal phenomenon in these seizures is a sudden generalised loss of tone. This may
manifest as a head drop, or, if the patient is standing, as a forward fall that the patient cannot
mitigate, often resulting in head and facial injuries.

Focal seizures (ILAE 2010)

It is well recognised that seizure manifestations in focal seizures often reflect activation of
underlying cortical areas. This may result in a subjective alteration of experience (aura),
transient impairment of cognition or language, behavioural alterations (e.g. clonic
movements of one part of the body), and autonomic manifestations (e.g. brady- or
tachycardia, pallor, hypersalivation). Complex behaviours such as semi-purposeful
automatisms (e.g. chewing, lip smacking, fumbling, pedalling), kicking and thrashing
movements, and shouting, humming, or laughter may be seen as well. These automatic
behaviours likely reflect activation or disinhibition of a specific cortical/subcortical network.
Consciousness may be preserved, altered, or lost during a seizure. The listed features may
occur in any combination.

The 1981 proposal emphasised alteration of awareness (‘simple’ partial seizure reflecting
retained awareness, and ‘complex’ partial seizure implying impaired awareness). It has been
recognised since that awareness cannot be easily judged during a seizure, unless the patient