Progressive Ataxia and Palatal Tremor with Hypertrophic Olivary Degeneration

A 60-year-old man presented with a 2.5-year history of progressive gait imbalance and dysarthria, with recurrent falls in the past year. Neuro-ophthalmic examination showed mild rotatory pendular nystagmus and palatal tremor without oscillopsia or ear clicks. Cognition revealed MoCA 22/30 with deficits in attention, repetition, abstraction, and delayed recall; language showed paraphasic errors with preserved comprehension. On neurologic examination, he had bilateral dysmetria on finger-to-nose and heel-to-shin testing and had moderate ataxia on gait assessment, with an inability to tandem. MRI brain demonstrated bilateral inferior olivary hypertrophy. FDG-PET demonstrated moderate increased uptake along the left, greater than right, medulla, corresponding with the area of suspected inferior olivary hypertrophy on prior MRI-a pattern reported in hypertrophic olivary degeneration, including progressive ataxia and palatal tremor (PAPT). There was also diffuse asymmetric left cerebellar hypometabolism, which, while nonspecific in isolation, most likely represents a diaschisis phenomenon related to asymmetric involvement of the inferior olivary nuclei. This is particularly given the absence of an alternative contralateral right supratentorial cortical hypometabolism to account for it. No other degenerative pattern was seen on PET. Routine labs were unrevealing. A comprehensive ataxia panel (Blueprint Genetics) was negative, including POLG variants and SCA repeat expansions. No structural, pharmacologic, or genetic etiology was identified to explain the clinical syndrome, although a neurodegenerative cause cannot be entirely excluded. The findings are consistent with sporadic progressive ataxia with palatal tremor (PAPT), supported by imaging evidence of hypertrophic olivary degeneration. Management emphasized fall prevention and rehabilitation, with medication for oscillopsia deferred, given minimal visual symptoms.