A distinctive reflex epilepsy syndrome of myoclonic jerks of the masticatory muscles elicited by reading.

Prevalence

Very low (0.2% in non-febrile epilepsies of childhood).

Age at onset

12 to 19 years (peak in late teens).

Sex

Males predominate (1.8 M/1 F).

Etiology

Genetically determined.

Clinical manifestations

Brief myoclonic jerks mainly restricted to the masticatory, oral, and perioral muscles, described as clicking sensations. They occur a few min to hours after reading. If the patient performs continuous reading despite jaw jerks, these may become violent and spread to trunk and limb muscles before generalized tonic-clonic seizures (GTCS) develop.

The majority of patients have a single GTCS, which is usually self-inflicted because of their curiosity to see what will happen if they continue reading despite jaw jerks or other manifestations. Other types of ictal manifestations (mainly visual hallucinations) in addition to the jaw myoclonus are rare.

Hand myoclonic jerking is common among those with writing precipitation of seizures (graphogenic epilepsy).

Some patients have prolonged, clearly focal, seizures that manifest with alexia and possibly dysphasia, while occasional absences may occur.

Precipitating factors

Reading (silently or aloud), talking (if fast or argumentative), writing, reading music, chewing, and other linguistic activities (language-induced epilepsy).

Diagnostic procedures

All tests apart from the EEG are normal.

Inter-ictal EEG

Usually normal.

Ictal EEG

Heterogeneous in morphology and topography. Brief discharges of sharp waves, which are bilateral with left-sided temporo-parietal preponderance.

Prognosis

Good. Seizures are mild.

Management options*

Clonazepam 0.5 mg to 1 mg taken at night is highly effective and this is superior to valproate, which is also used. Modification of reading and talking habits may be successful.

*Expert opinion, please check FDA-approved indications and prescribing information

This page was adapted from:

The educational kit on epilepsies: The epileptic syndromes By C. P. Panayiotopoulos Originally published by MEDICINAE 21 Cave Street, Oxford OX4 1BA

First published 2006 and reprinted in 2007