Oculopalatal tremor following sequential medullary infarcts that did not cause hypertrophic olivary degeneration

The syndrome of oculopalatal tremor is a known consequence of lesions in the dentate-olivary pathway. Hypertrophic degeneration of the inferior olive is a recognized pathological correlate of these lesions and hypothesized to cause tremorogenic olivary hypersynchrony. However, oculopalatal tremor also occurs in Alexander disease, which produces severe inferior olive degeneration without intervening hypertrophy.

Serial clinical, imaging, video-oculography and kinematic tremor recording of a patient with oculopalatal and limb tremor.

We report an unusual presentation of oculopalatal tremor and right upper extremity myorhythmia following sequential right dorsolateral and left anteromedial medullary infarcts directly involving both inferior olives. As in adult Alexander disease, our patient did not have hypertrophic olivary degeneration during 10 years of follow-up.

Contemporary theories have emphasized the role of cerebellar maladaptation in "shaping" oscillations generated elsewhere, the inferior olive in particular. Our patient and published Alexander disease cases illustrate that oculopalatal tremor can occur in the absence of hypertrophic olivary degeneration. Therefore, cerebellar maladaptation to any form of olivary damage may be the critical pathophysiology in producing oculopalatal tremor.