Epilepsy Center, University Hospital Freiburg, Germany
Ictal laughter is the cardinal clinical sign of gelastic seizures in hypothalamic hamartomas and may also occur in extrahypothalamic epilepsies. Laughing consists of an affective and a motor component. It has been suggested that the affective component may result from an involvement of temporobasal structures, whereas the motor part is related to an involvement of the mesial frontal cortex. So far, evidence is based on a limited number of cases with spontaneously recorded seizures or in whom electrical stimulation of invasive intracranial EEG recordings has been performed. We report a patient who suffered from epigastric psychic auras, complex partial seizures with a gelastic component and secondarily generalized seizures. To evaluate a possible epileptogenic role of the hippocampus and dysplastic region in the right mid-temporal gyrus, intracranial monitoring with subdural electrodes over the temporobasal and temporolateral regions, as well as a deep brain electrode in the hippocampus, were performed. During the intial part of the seizure, consisting of an intense retrosternal ascending feeling with sexual connotation, rhythmic spikes in temporolateral contacts were detected. Concomitant with the development of smiling and laughter, a rhythmic activity over the temporobasal regions evolved. The patient became seizure-free following right temporal lobe resection. This case supports the assumption that ictal involvement of temporobasal structures is crucial for gelastic seizure components in patients with temporal lobe epilepsy. Progression to temporobasal regions was associated with the feeling of happiness whereas motor components of laughter occurred later. These findings are in accordance with the interpretation of surface recordings by Dericioglu and co-workers in a similar previous case. [Published with video sequences].