Gelastic epilepsy: symptomatic and cryptogenic cases.

PURPOSE: To describe the etiology, characteristics, and clinical evolution of epilepsy in patients with gelastic seizures (GSs). METHODS: Nine patients whose seizures were characterized by typical laughing attacks were observed between 1986 and 1997. Patients were selected based on electroencephalogram (EEG) or video-EEG recordings of at least one GS and on magnetic resonance imaging (MRI) study. RESULTS: Five patients were affected by symptomatic localization-related epilepsy (LRE), with four of the patients' disorders related to a hypothalamic hamartoma (HH) and one to tuberous sclerosis (TS) without evident hypothalamic lesions. In four patients (the cryptogenic cases) MRI was negative also in these cases, clinical and EEG data suggested a focal origin of the seizures. The epileptic syndrome in the HH cases was usually drug-resistant, and was surgically treated in two of the patients. The patient with TS became seizure free with vigabatrin. In the cryptogenic cases, the ictal, clinical, and EEG semiology were similar to the symptomatic cases: the clinical evolution was variable, with patients having transient drug resistance or partial response to treatment. No cognitive defects were observed in the cryptogenic patients. None of the nine patients had precocious puberty. CONCLUSIONS: We confirm the frequent finding of HHs in GSs and further underline how GSs may also be observed in patients without MRI lesions and with normal neurologic status. In these patients, clinical and EEG seizure semiology is similar to symptomatic cases, but the clinical evolution is usually more benign.