[A case of lobar atrophy with stereotypic unusual laughing].

We report a case of a Pick's disease (frontal predominant type) with unusual laughing. The patient was a 54-year-old, right handed, female. The patient began to show low activity and inappropriate laughing at about 51 years. She did not speak at all and showed weird laughing with a voice "hi hi hi hi hi hi" frequently at first presentation. When asked some questions, she sometimes answered with a nod. Almost all of her laughing did not match with the situation and seemed to lack a relationship between affective change and observed expressions. The laughing could be elicited by non specific and varied stimuli. She often interrupt laughing voluntarily unlike pathological laughing. Neurological examination revealed visual rooting reflex and forced grasping reflex but there was no signs of pseudobulbar palsy often observed in patients with pathological laughing. Her electromyogram of facial expression during the laughing showed that electric discharge of M. corrugator supercilii was over 4 times as much as that in normal laughing. And it showed also that the duration of her laughing was several seconds as normal laughing. CT and MRI scans demonstrated atrophy in the fronto-temporo-parietal lobe bilaterally (L > R), most prominent in the frontal lobe. SPECT scan showed a significant diminution of blood flow in the atrophic region. An EEG was normal. We consider that the laughing of the present case is not due to an emotional disturbance but rather a disorder of affective expression as pathological laughing.