Progressive Cerebral Atrophy and Cognitive Decline Without Cerebral Lesion in Neuromyelitis Optica Spectrum Disorder: A Case Report

Neurological deficits in neuromyelitis optica spectrum disorder (NMOSD) are conventionally thought to result from acute relapses, unlike multiple sclerosis (MS), which frequently progresses without relapse due to neurodegeneration. However, we present the case of a 41-year-old male patient who showed progressive bilateral frontal lobe atrophy over nine years, although acute relapses were limited to the medulla and spinal cord. Neuropsychological testing indicated cognitive decline. This case demonstrates progressive cerebral atrophy and cognitive decline, independent of relapses in NMOSD, possibly suggesting subclinical dying-back degeneration.