Five main types of seizures are recognised
Subtle seizures
most common type; subtle clinical manifestations
ocular movements (random and roving eye movements to sustained conjugate tonic deviation with or without jerking)
Eyelid blinking or fluttering, eyes rolling up, eye opening, fixation of a gaze or nystagmus may occur alone or with other ictal manifestations
oral–buccal–lingual movements (sucking, chewing, smacking and tongue protrusions)
progression movements (rowing, swimming, pedalling, bicycling, thrashing or struggling movements)
complex purposeless movements (sudden arousal with episodic limb hyperactivity and crying)
Clonic seizures
rhythmic jerks that may localise in a small part of the face or limbs, axial muscles and the diaphragm, or be multifocal or hemiconvulsive.
Multifocal clonic seizures may migrate to other body parts or other limbs. Todd’s paresis follows prolonged hemiconvulsions.
Tonic seizures
manifest with sustained contraction of facial, limb, axial and other muscles
may be focal, multifocal or generalised, symmetrical or asym-metrical
Truncal or limb tonic extensions imitate decerebrate or decorticate posturing (occur particularly in pre-term infants and have a poor prognosis because they frequently accompany intra-ventricular haemorrhage)
Myoclonic seizures
rapid, single or arrhythmic repetitive jerks. They may affect a finger, a limb or the whole body. They may mimic Moro reflex and startling responses
more frequently in pre-term than in full-term infants indicating, if massive, major brain injury and poor prognosis.
healthy pre-term and, although rarely, full-term neonates may have abundant myoclonic movements during sleep
Neonates have cortical, reticular and segmental types of myoclonus, similar to adult forms (Scher, 1985).
Spasms
Autonomic ictal manifestations
autonomic ictal manifestations commonly occur with motor manifestations in 37% of subtle seizures
paroxysmal changes of heart rate, respiration and systemic blood pressure, salivation, pupillary changes
Apnoea, as an isolated seizure phenomenon unaccompanied by other clinical epileptic features, is rare
The duration of neonatal seizures is usually brief (10 s to 1–2 min) and repetitive with a median of 8 min in between each seizure. Longer seizures and status epilepticus develop more readily at this age, but convulsive neonatal status epilepticus is not as severe as that of older infants and children.