Abstracts

The term praxis-induced seizures has been recently proposed for a variety of reflex epilepsies induced by complex cognitive and motor tasks. Little is known on the pathophysiology of these rare epileptic syndromes.
We report a 25 year-old woman with reflex seizures systematically induced by goal-oriented oculomotor tasks. The ictal events were documented by continuous video-EEG monitoring. A total of three subtraction ictal SPECTs coregistered to MRI (SISCOM) were performed.
A total of 3 seizures were recorded. The most effective triggers were the manipulation of electronic devices, such as cellular phones or pocket computer games. Seizures were stereotyped, and consisted in a sensory aura involving the left hand, followed by clonic movements of the left hemiface and arm, along with left cephalic deviation lasting 30 seconds. The patient remained conscious throughout the seizure. Ictal EEG shows rhythmic theta activity starting over the right posterior quadrant, and rapidly spreading to both posterior regions. Interictal EEGs were normal. A SISCOM study was performed for each ictal event (n=3), respectively at 14 , 11 and 1 sec. Early injected SISCOM (1 sec) revealed an activation of the right occipital lobe and ipsilateral rolandic region. In turn, later injections (11 and 14 secs) resulted in activation of the right Rolandic region or antero-superior portion of the right temporal lobe.
Sequential analysis of SISCOM in praxis-induced seizures suggested an initial activation of the right occipital lobe, rapidly followed by spreading to the ipsilateral Rolandic and temporal lobe regions. Visual input combined with motor activity and decision making were essential to triggering seizures. This study gives some insight on the neuronal network involved in this rare form of epilepsy.