A 55-year-old man with long-standing alcohol dependence walks with a broad-based, staggering gait; heel-to-toe walking is impossible. Limb coordination tests such as finger-nose pointing are performed normally while seated, and nystagmus and dysarthria are absent. MRI shows atrophy of which cerebellar region?

• A Dentate nucleus
• B Flocculonodular lobe
• C Right cerebellar hemisphere
• D Anterior lobe of the vermis ✓

Explanation

Alcoholic cerebellar degeneration selectively damages the anterior superior vermis, which controls axial musculature and gait, so truncal and gait ataxia dominate while limb coordination tested with the patient supported remains relatively preserved. Flocculonodular damage produces truncal ataxia with vertigo and nystagmus from vestibular connections, and hemisphere or dentate lesions give ipsilateral limb ataxia, intention tremor and dysdiadochokinesia, patterns absent here.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.