~30% to 50% of all epilepsies; 2/3 mesial and 1/3 lateral TLE.

Age at onset
Mainly late childhood to adolescence.

Males = females.

Neurological and mental state
Depends on etiology.

Symptomatic, cryptogenic, idiopathic. Hippocampal sclerosis is the most common. Other structural causes: tumors, vascular, malformations of cortical development, traumatic, viral and other infectious and parasitic disorders, and cerebrovascular disease.

Clinical manifestations
These depend on whether the seizures are of mesial TLE or lateral TLE.

Post-ictal symptoms are very frequent and often severe.

Secondarily generalized tonic-clonic seizures (GTCS) are infrequent in properly treated patients.

Complex focal status epilepticus occur, particularly in untreated patients. It is less common than absence status epilepticus of idiopathic generalized epilepsy.

Diagnostic procedures
MRI is abnormal in >90% of symptomatic cases.

Inter-ictal EEG
Background of symptomatic cases is usually abnormal, with posterior lateralized slow waves in lateral TLE. In mesial TLE, 1/3 show unilateral or bilateral anterior temporal spikes. In lateral TLE, half show mid-temporal or posterior temporal spikes. A single routine EEG may be normal or show mild and non-specific abnormalities in half of the mesial TLE. Regional temporal inter-ictal runs of slow waves, which are of lateralizing value, are recorded in about half of patients.

Ictal EEG
Rhythmic slow activity (around 4 to 7 Hz) that appears over the affected temporal lobe, before or simultaneously with clinical events. Fast spiking is more common in lateral TLE than in mesial TLE.

In 1/3 of mesial TLE cases, no appreciable changes occur.

Frequency, severity, and response to treatment vary considerably from good to intractable and may be progressive, depending mainly on the underlying cause.

Differential diagnosis
Non-epileptic conditions and seizures arising from other brain locations. Lateral temporal lobe seizures usually lack features usually exhibited in mesial TLE such as (1) ascending epigastric aura or fear; (2) eye blinking and aggressive behavior; and (3) contralateral dystonia, searching head movements, body shifting, hyperventilation, and post-ictal cough or sigh.

Management options*
Drug treatment, similar to any other type for focal seizures, is usually effective and this should be initiated as soon as possible. Carbamazepine, levetiracetam and lamotrigine are the drugs of first choice.

Neurosurgical treatment provides excellent chance of cure in hippocampal and other localized pathological conditions.

*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

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