Case 22: The Unsteady walker

A 45-year-old man presents with a 3-month history of worsening unsteadiness while walking, slurred speech, and difficulty performing coordinated tasks like buttoning his shirt. He has a past history of chronic alcohol use. On examination, he exhibits a wide-based gait, dysdiadochokinesia, and intention tremor. MRI shows cerebellar atrophy. What is the most likely diagnosis, and which part of the brain is primarily affected?