Unknown but may be more common than diagnosed.

Age at onset
Teenage or early adult life; median 25 years. Not before 10 years of age.

Females (58%) > males.

Neurological and mental state

Autosomal dominant inheritance with reduced 60% penetrance. Genetically heterogeneous.

Clinical manifestations
Simple focal seizures (90%) manifest with a galaxy of déjà vu and other subjective complex internal sensations (nearly all) alone or together with autonomic disturbances. Other symptoms include fear and panic, visual and auditory illusions of distortions of light and sound, and somatosensory sensations of diffuse, not localized, numbness and tingling. These may progress to complex focal seizures (66%). Generalized tonic-clonic seizures (GTCS; 2/3 of patients) are infrequent (<1/year) and usually prior to medication.

Rising epigastric sensation does not occur.

Diagnostic procedures
MRI is normal but severe cases may show hippocampal atrophy, including rare examples of familial hippocampal sclerosis. Diffuse small high signal areas on T2-weighted images may be seen. Ipsilateral temporal hypometabolism in inter-ictal 18F fluoro-deoxyglucose (FDG)-PET.

Inter-ictal EEG
Usually normal (half the cases) or with mild focal slow waves (28%) or sparse sharp- and slow-wave complexes localized in the temporal region and usually unilateral (22%). Sleep may activate epileptiform abnormalities.

Ictal EEG
Temporal lobe seizure discharge but occasionally no EEG change.

Usually excellent; 16% with mild simple focal seizures alone would never know that this is epilepsy if other family members were not affected. Of those with overt seizures, 66% have complex focal seizures and GTCS, which are infrequent and respond well to anti-epileptic medication. For seizures to continue after drug treatment is rare (10% to 20%). Long remissions, with or without therapy, are common. A more severe clinical spectrum may exist.

Differential diagnosis
Very mild and infrequent seizures with predominantly déjà vu from normal phenomena and hippocampal epilepsy.

Management options
Easily controlled with AEDs indicated for focal seizures.

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

Authored By: 
C. P. Panayiotopoulos MD, PhD, FRCP
Authored Date: 
Reviewed By: 
Steven C. Schachter MD
Sunday, June 1, 2008