HEMIBALLISMUS: /ETIOLOGY AND SURGICAL TREATMENT BY

Hemiballismus is a relatively uncommon hyper-kinesia characterized by vigorous, extensive, and rapidly executed, non-patterned, seemingly pur-poseless movements involving one side of the body. The movements are almost unceasing during the waking state and, as with other hyperkinesias con-sidered to be of extrapyramidal origin, they cease during sleep. Clinical Aspects Cases are on record (Whittier, 1947) in which the abnormal movements have been confined to a single limb ( " monoballismus ") or to both limbs of both sides ( " biballismus ") (Martin and Alcock, 1934; von Santha, 1932). In a majority of recorded instances, however, the face, neck, and trunk as well as the limbs appear to have been involved. The patient usually retains a measure of voluntary control over the affected member so that acts such as walking, putting on slippers, and touching the hand to the face can be performed even if with difficulty. The ballistic movements cannot however be voluntarily checked for more than a few moments at a time. The muscle tonus of the involved limb(s) may be normal but in many instances is slightly diminished (Martin and Alcock), and in consequence of the reduced initial tension of the muscles the deep reflexes of the affected limbs are often moderately diminished. The vast majority of patients are at or beyond middle life at the time of onset of hemiballismus. However, reports of patients as young as seven (Bonhoeffer, 1930) and eighteen (Bianchi, 1909) years have been recorded. There appears to be no significant difference in sex incidence. Spontaneous recovery is not to be expected and by far the majority of patients succumb within a few days to several months of progressive exhaustion, cardiac failure, or pneumonia (Grinker and Bucy, *Case I of this communication was reported with motion picture illustrations at the Sixteenth Annual Meeting of the Harvey Cushing Society on August 19, 1948, at San Francisco, Cal. The paper i