Abstracts

Rationale: Gelastic seizures are rare ictal manifestations. They consist of bursts of laughter and are classically associated with hypothalamic hamartoma. However, few patients with partial epilepsy originating from the temporal or frontal lobe have been reported to present seizures with laugher as their main symptom. The motor act of laughter and its emotional content are separately represented on the cerebral cortex, as suggested by recent reports of cerebral electrical stimulation eliciting laughter . We evaluated the frequency and the semiology of ictal laughter (IL) in patients with partial epilepsies and we analysed the lateralizing and localizing value of different types of IL. Methods: We reviewed the video-EEG recordings of epileptic patients in presurgical evaluation in our Unit from 2001 to 2008. Video-recordings of seizures were reviewed by two independent investigators blinded to the patients’ clinical data. IL was defined by a sonorous and rhythmic expulsion of air from the lungs modulated by laryngeal muscles, usually associated with movement of the muscles of the face, occurring without provocative external factor. Results: We identified 32 patients who laughed during their seizures (n = 410 seizures). Sixteen patients presented a vocalisation which did not meet our criteria for ictal laugh or had a laugh caused by a non-ictal mechanism (laughter just before the clinical and/or EEG onset of the seizures, laughter after the end of the seizures or provoked laugher). The other sixteen patients (n = 195 seizures) experienced an IL at least once during their recorded seizures (n=94 seizures). Among these patients, SEEG recordings were performed in 4 patients (n =39 seizures). The video analysis of the 91 seizures with IL recorded from scalp EEG and the 3 seizures recorded by SEEG allowed the distinction of 3 types of IL: (i) a discreet, non-noising laugh, (ii) a noising belly laugh and (iii) a sonorous rhythmic, sniggering laugh. The result of the presurgical investigations of each patient will be presented in order to attempt to correlate the epileptogenic zone to the types of IL. In two cases the intracerebral electrical stimulation elicited laughter. Conclusions: The lateralizing and localizing value of these clinically three different types of IL will be discussed. The networks involved in IL will be analysed in view of those involeved in physiological laughter.