[Clinical analysis of benign transient shuddering-like involuntary movement in elderly people]

We described 9 patients who developed acute onset benign transient shuddering-like involuntary movement in elderly people. There was no consciousness disturbance or sensorimotor dysfunction. There were finger tremor, dysarthria, or gait disturbance in some patients. Asterixis was observed in the upper extremities in 2 patients. Duration of an involuntary movement was less than 1 second, and the series of the involuntary movements continued for several days. This state appeared acutely and disappeared within 0.5 -4 days in the natural course without any sequelae. Oral administration of clonazepam was very effective to suppress this tremulousness. Seven of 9 patients developed recurrence. Although the cause of this syndrome remains unknown, we believe that this condition is clinically important for differential diagnosis of acute onset involuntary movements in elderly people.