Symptomatic laughter in a patient with orbitofrontal seizure: A surgical case with intracranial...

A rare case of orbitofrontal lobe epilepsy manifesting gelastic seizure is reported.

A 49-year-old woman had developed weekly complex partial seizures consisting of nonverbal vocalization and unresponsiveness followed by laughter. Magnetic resonance imaging revealed a round tumorous lesion at the posterior side of the right rectal gyrus and medial orbitofrontal gyrus. Neuroimaging studies and electrophysiological examinations, including intracranial electroencephalographic monitoring, suggested the existence of an epileptogenic zone in the ipsilateral orbitofrontal gyrus, including the lesion.

After partial right prefrontal lobectomy including lesionectomy, the patient became seizure-free during a follow-up period of 33 months. We speculated that the limbic system, including the orbitofrontal lobe and temporal structures, which have a strong connection with the pontine nuclei, might be involved in this patient's gelastic seizure.

Except for impaired consciousness, the clinical manifestations did not correspond to the characteristics of orbitofrontal seizure described by the International League Against Epilepsy. Symptomatic laughter in epilepsy that originates from the orbitofrontal lobe is very rare. Intracranial electroencephalographic findings and ictal symptomatology associated with epileptogenesis in this rare case are discussed.