Deep gray matter atrophy in neuromyelitis optica spectrum disorder and multiple sclerosis

We investigated changes in deep gray matter (DGM) volume and its relationship to cognition and clinical factors in a large cohort of patients with neuromyelitis optica spectrum disorder (NMOSD) and compared them with results from multiple sclerosis (MS).

Brain magnetic resonance imaging (3 Tesla) and clinical data from 91 patients with NMOSD, 52 patients with MS and 44 healthy controls (HCs) were prospectively evaluated. Differences in DGM volumes were compared among groups. The relationships between DGM atrophy and clinical variables were also analysed.

Patients with NMOSD exhibited significantly reduced thalamic volumes compared with HCs (P = 0.029), although this atrophy was less severe than that seen in patients with MS (P < 0.001). DGM atrophy was restricted to the thalamus in NMOSD, but it was broadly distributed in MS. Patients with NMOSD with cognitive impairment (CI) exhibited more severe thalamic atrophy than those with cognitive preservation (P = 0.017) and HCs (P = 0.003), whereas patients with MS with CI revealed DGM atrophy across the entire structure, with the exception of the bilateral pallidum, left hippocampus and amygdala, relative to HCs. The Expanded Disability Status Scale score was correlated with thalamic atrophy in both NMOSD and MS. Patients with NMOSD with brain lesions demonstrated more severe thalamic atrophy than did those without brain lesions and HCs (P < 0.001).

The DGM atrophy was less severe and more selectively distributed in NMOSD than in MS. Thalamic atrophy was associated with clinical disability, including CI, in both NMOSD and MS.