LAUSR

A 20-year-old man presented with vertigo followed by hourly episodes of dysarthria and incoordination lasting 5–20 seconds (video 1). Neurologic examination was normal between episodes. The only brain/spine MRI lesion was in the right superior cerebellar peduncle (figure, A). CSF analysis revealed elevated white blood cells (6/μL [normal, 0–5]) and oligoclonal bands (≥4). Paroxysmal dysarthria–ataxia associated with CNS demyelination was diagnosed and episodes resolved with oral acetazolamide 250 mg twice daily. Subsequent MRI of the brain and spine (figure, B) confirmed multiple sclerosis. Paroxysmal dysarthria–ataxia arises from ephaptic transmission within midbrain or cerebellar multiple sclerosis lesions and may respond to carbamazepine or acetazolamide.1 It should be distinguished from genetic or contactin-associated protein-like-2 (CASPR2) immunoglobulin G–associated episodic ataxia.2