Abstracts

Gelastic seizures (epileptic laughter) occur most commonly in conjunction with hypothalamic harmartomas, which present in childhood, with or without associated endocrine dysfunction. Gelastic seizures occur less commonly with lesions in other parts of the limbic system. We evaluated two patients with gelastic seizures, characterized their clinical events, and compared them with similar cases which have been previously described in an effort to better characterize gelastic seizures of non-hypothalamic origin. We recorded prolonged video-EEG (VEEG) in two women, each of whom had been previously diagnosed to have a psychiatric disturbance because of episodes of inappropriate laughter. MRI brain imaging with standard seizure protocol was performed in each case. Review of previously published cases of gelastic and dachrystic seizures of non-hypothalamic origin was accomplished to ascertain and compare reported clinical manifestations, demographic features, prognosis, and approaches to treatment. A 42 year old woman suffered a closed head injury in an equestrian exercise. One year later, she began having episodes of staring and loss of contact, associated with automatisms invariably accompanied by laughter. She also had generalized tonic-clonic seizures.
MRI: right mesial temporal sclerosis. EEG: right anterior and mesiobasal temporal lobe spikes. VEEG: laughter a prominent component of 10/10 recorded complex partial seizures. Six of ten events were localized to right temporal lobe by scalp and sphenoidal EEG. Ictal SPECT demonstrated increased uptake in right temporal lobe. She awaits right amygdalohippocampectomy.
A 48 year old woman developed symptoms of depression, followed by episodes of brief staring and inattentiveness precipitated by psychological stress. She had rather mirthless laughter as a part of these episodes. She experienced a generalized tonic-clonic seizure, prompting neurological evaluation.
Interictal EEG: normal. MRI brain scan: normal. Prolonged VEEG, with sphenoidal leads: interictal left anterior and mesiobasal temporal spikes. Rhythmic theta activity began in left mesiobasal temporal lobe during ictal recording of typical episode. Her events have been controlled with a combination of phenytoin and levetiracetam.
We located 62 cases of gelastic or dachrystic seizures of non-hypothalamic origin, including temporal, cingulate, and frontal lobe foci. Gelastic seizures disproportionately took origin from right cerebral hemisphere, whereas dachrystic seizures overwhelmingly orginated in left cerebral structures. In a few instances, gelastic and dachrystic seizures occurred in the same person. 1. Epileptic laughter may be a prominent feature of temporal lobe seizures.
2. Gelastic seizures are more likely to occur in seizures of right temporal or frontal lobe lobe origin, whereas dachrystic seizures are much more likely to orginate in the left cerebral hemisphere.