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Juvenile myoclonic epilepsy (JME)
JME is an idiopathic generalised epilepsy syndrome with age-related onset, commonly
between the ages of 12 and 18 years. The sex distribution is equal. Bilateral, single or multiple
irregular myoclonic jerks occur, mainly in the upper limbs. Most of the patients who present
for treatment also have tonic-clonic seizures and many have absence seizures. The tonic-
clonic seizures predominantly occur soon after awakening.

Patients often present with a history of one or more episodes of tonic-clonic seizures on
awakening. The doctor should always ask specifically about morning myoclonic jerks, which,
if not severe, may be viewed as slowness or clumsiness. Specific enquiry should also be made
about ‘blank spells’. Patients often do not declare myoclonic jerks or absence seizures
because they do not realise that these are epileptic seizures but if this information is not
available a diagnosis of JME is likely to be missed. It is important to diagnose this condition
because most cases respond very well to sodium valproate. This often needs to be continued
long term even if the patient is seizure free for years, since the chance of relapse is high if
sodium valproate is stopped. The addition of lamotrigine may be effective in those patients
who do not respond adequately to monotherapy with sodium valproate. Levetiracetam has
been shown to be effective in treating the myoclonic seizures in JME and has a licence for
this indication.

Juvenile absence epilepsy (JAE)
The onset of JAE is typically between the ages of 10 and 17 years, with males and females
equally affected. Subjects are usually neurologically normal and a family history of epilepsy
is common. The photosensitivity rate is high. Over 80% also have generalised tonic-clonic
seizures. The absence seizures usually respond well to treatment with anti-absence
medication such as sodium valproate, ethosuximide or lamotrigine.

Epilepsy with generalised tonic-clonic seizures on awakening
The peak onset of this syndrome is around puberty. Seizures occur exclusively or
predominantly soon after awakening from sleep at any time of the day, with a second seizure
peak during evening relaxation. Seizures may be precipitated by sleep deficit, excessive
alcohol or sudden arousal.

There is some overlap between these three syndromes. This has generated much discussion
on the way in which these three generalised epilepsies should be classified7,8.

Benign partial seizures in adolescence
This syndrome needs to be distinguished from the very different syndrome of benign partial
epilepsy of childhood. Age of onset is between 10 and 20 years, with a peak around 1314
years. It is more common in boys. There is usually no family history and no cognitive or
neurological impairment. The subject has simple or complex partial seizures, which can be
secondarily generalised. There may be a cluster of 2–5 seizures in a 3648 hour period. The
patient may have only one episode of either a single seizure or a single cluster of seizures.
The EEG is typically normal or shows only mild abnormality, in contrast to the syndrome of
benign partial epilepsy of childhood, in which centrotemporal (rolandic) spikes occur.
Because benign partial seizures in adolescence often present with only one seizure or a cluster
of seizures, treatment should be avoided unless there is a recurrence or unless there are
particular reasons for treating.