Relatively small; ~6% in neurosurgical series.

Age at onset
Any age.

Males = females.

Neurological and mental state
Depends on etiology.

Symptomatic, cryptogenic, or idiopathic.

Clinical manifestations
Simple focal seizures predominate. Subjective symptoms are somatosensory, disturbances of body image (somatic illusions), vertiginous, visual illusions, or complex formed visual hallucinations.

Somatosensory seizures (2/3): Paresthetic, dysesthetic, and painful sensations (numbness, thermal, pricking, tight, electric). Pain is sometimes exacerbating. Face, hand, and arm (per the sensory homunculus) are mainly involved. Symptoms may be static or march in Jacksonian manner.

Somatic illusions (second most common): Distorted posture, limb position, or of movement, an extremity or a body part being alien or absent. They mainly emanate from the non-language-dominant cerebral hemisphere. Inability to move one extremity or a feeling of weakness in the hand is contralateral to the epileptogenic zone.

Vertigo and other vertiginous sensations (~10%).

Visual illusions and complex formed visual hallucinations (~12%); images look larger or smaller, close or far away, or moving although static; metamorphopsia, palinopsia.

Genital sensations or orgasm may occur.

Dominant temporal-parietal regions: Linguistic disturbances of alexia with agraphia and miscalculations.

Non-dominant parietal-occipital-temporal regions: Spatial disorientation.

Simple focal seizures often spread to extra-parietal regions, producing unilateral focal motor clonic manifestations (57% of patients), head and eye deviation (41%), tonic posturing of usually one extremity (28%), and automatisms (21%).

Most of the patients also suffer from secondarily generalized tonic-clonic seizures (GTCS).

Post-ictal symptoms include Todd's paralysis (22%) and dysphasia (7%).

Duration is several sec to 2 min. Sensory epilepsia partialis continua is rare.

Frequent, sometimes many per day, and often in multiple clusters.

Precipitating factors
Movements of the affected part of the body, tapping, or other somatosensory stimuli.

Predominantly diurnal.

Diagnostic procedures
MRI is abnormal in ~60%.

Inter-ictal EEG
Usually normal or focal slow waves and spikes.

Ictal EEG
80% of simple focal sensory seizures do not show appreciable changes.

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

Differential diagnosis
Somatosensory seizures are often misdiagnosed as psychogenic, transient ischemic attacks, or migraine with aura, in that order.

Management options*
AEDs indicated for focal seizures are usually effective. Carbamazepine, levetiracetam and lamotrigine are the drugs of first choice. Neurosurgery for symptomatic cases: 65% become seizure free or have rarer seizures.

*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