Abstract
Although the so-called extrapyramidal syndromes are most frequently seen after infection, intoxications, vascular lesions, or disturbances of brain metabolism, they also occur in association with various intracranial tumors. However, it should be emphasized that the involuntary movements observed in patients with intracranial tumors are seldom so bizarre as those occurring in other conditions, and usually consist of various types of tremor or changes in muscular tone only. The observation that sometimes prompt, complete, and permanent disappearance of such involuntary movements follows removal of the tumor justifies the hypothesis that these movements are not necessarily produced by a lesion of one or the other of the basal ganglia, as commonly thought, but are, rather, manifestations of a disturbance in the central nervous regulation of voluntary movements and the maintenance of normal posture. A careful analysis of the relevant literature has revealed that there have been instances of tremor, hypo- or hypertonus,