Startle Epilepsy Associated with Infantile Hemiplegia (SEIH): Video-Polygraphic Features and Long-Term Outcome

Abstract

Objective: The aim of this study was to investigate the video-polygraphic features and the long-term outcome of epilepsy in two patients with startle epilepsy associated with infantile hemiplegia (SEIH).

Material and Methods: Two patients (patient 1: a 14-year-old girl; patient 2: a 17 year-and-half-year-old girl), with hemiparesis and moderate mental retardation, underwent a full clinical and neurophysiological examination with video-polygraphic monitoring and recording of startle-evoked seizures. The follow-up was 9 years from epilepsy onset in patient 1, and 8 years from epilepsy onset in patient 2.

Results: Firstly, video-polygraphic recordings of startle-evoked seizures, triggered by unexpected auditory stimuli, showed tonic asymmetrical postures with ictal EEG characterized by an abrupt and diffuse electrodecremental pattern or a seizure discharge predominant over the vertex and anterior regions controlateral to the posturing limbs. Electromyogram recording showed a prevalent involvement of proximal muscles with a concomitant tachycardia and apnoea. In particular, in patient 1 ictal heart rate was high, with persisting tachycardia for 60–120 s after the end of seizures. Secondly, a high seizure frequency persisted throughout the course of the disease, as seizures were medically refractory to all currently available anti-epileptic drugs.

Conclusions: The long-term outcome of epilepsy in SEIH, with constantly high seizure frequency, suggests an early surgical intervention, avoiding years with unsuccessful drug treatments and poor quality of life.

Key words

startle epilepsy - infantile hemiplegia - long-term prognosis - video-polygraphy - epilepsy surgery

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