Dissociated Pendular Nystagmus in Oculopalatal Tremor with Bilateral Inferior Olivary Hypertrophy

Oculopalatal tremor (OPT) is characterized by a synchronous tremor of the palate and eyes that may also involve other muscles from the branchial arches. The nystagmus of OPT may be conjugate, disconjugate or disjunctive. In the previous studies, only symmetric pendular nystagmus was observed in the bilateral hypertrophic changes of inferior olivary nucleus (ION), while dissociated pendular nystagmus was associated with either ipsilateral or bilateral changes. We report a case of dissociated pendular nystagmus in bilateral olivary hypertrophy.