30th April 2024

A 30-year-old man presents with a 3-month history of intermittent blurred vision in his right eye and episodes of numbness and tingling in his left arm and leg.

A 30-year-old man presents with a 3-month history of intermittent blurred vision in his right eye and episodes of numbness and tingling in his left arm and leg. He also reports feeling unusually tired and having difficulties with balance. His symptoms tend to fluctuate in intensity and have been progressively worsening. There is no significant past medical history, and he is not on any medication.

Which investigation is most likely to confirm the diagnosis?