A-2 Neuropsychological and Neuropsychiatric Symptoms Following Hypertrophic Olivary Degeneration

Abstract

Abstract Objective: Hypertrophic Olivary Degeneration (HOD) is a rare neurological condition causing hypertrophy and eventual degeneration of the inferior olivary nucleus via transneuronal degeneration in the dentato-rubro-olivary pathway (DROP), or Guillain–Mollaret triangle. HOD is considered unique because the olive initially becomes hypertrophic rather than atrophic. Etiology is often cerebral vascular insult, cavernous malformation, surgical resection, and neurological disease, albeit cause may be unclear. While the neurologic and imaging findings have been well delineated in the literature, few studies investigate the neuropsychological impact. Methods: With consent, a review of the medical chart was conducted of a 39-year-old female with hypertension referred for assessment due to progressive cognitive, motor, and psychiatric symptoms. Results: Physical symptoms included progressive limb and trunk ataxia, palatal tremor, and opsoclonus myoclonus that plateaued within 4 years. Initial Magnetic Resonance Imaging (MRI) revealed bilateral, nonenhancing hyperintensity of the pontomedullary junction and enlargement of the inferior olive. Subsequent MRI displayed cerebellar atrophy. Cognitive assessment documented significant executive, language, spatial and fine motor dexterity deficits, alongside depression, anxiety, emotional blunting, and passive suicidality. She reported believing her neighbors were listening and following her in public. She remained semi-independent in daily living. Conclusions: This is the first case study that captures the neurocognitive profile associated with HOD and associated degeneration of DROP. This case highlights the potential for Cognitive Cerebellar Affective Syndrome (CCAS) to arise from damage to adjacent cerebellar pathways via transneuronal degeneration of brainstem circuits. It also provides evidence for the presence of delusions within CCAS as dysmetria of thought.