The clinical characteristics and pathophysiology of the phenomenon of palatal myoclonus are not yet clearly understood. Since 1886 case reports of this phenomenon have appeared in the literature periodically,* and, although the rate and other physical characteristics have been described, little can be found concerning observations of these movements under various conditions, both spontaneous and induced, that might distinguish them from other abnormal motor phenomena. Also, there has been a relative paucity of satisfactory postmortem studies. Evidence based on approximately eight adequate pathologic reports points to the inferior olive as the structure primarily implicated in the production of these abnormal movements. Except for Freeman's case,7 in which a lesion in the central tegmental fasciculus was found, the major pathology was located in one or both inferior olives. One inferior olive usually appeared "swollen" as compared with the other, and, therefore, the term "pseudohypertrophy" was used. Although other structures, such