21st July 2023

A 64-year-old man presents with complaints of ataxia and difficulty reading.

A 64-year-old man presents with complaints of ataxia and difficulty reading. He reports that the words are jumping around on the page. Otherwise, he feels well. His past medical history includes hypertension and type 2 diabetes, which is diet controlled. Medication includes ramipril and amlodipine.
On examination, his eye movements are restricted to the downward gaze. Other cranial nerves examination is unremarkable.

Which of the following is the most likely diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.