Disease-specific patterns of glymphatic-related dysfunction between multiple sclerosis and neuromyelitis optica spectrum disorder

Background Glymphatic dysfunction has been reported in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), yet disease-specific patterns of glymphatic-related impairment and their structural and cognitive consequences remain poorly characterized. Methods This study enrolled 196 MS patients, 88 NMOSD patients, and 108 healthy controls (HC). Glymphatic-related function was assessed using diffusion tensor image analysis along the perivascular space (DTI-ALPS) and periventricular diffusivity (PVeD). Between-group differences, partial correlations with structural and clinical outcomes, AQP4 subgroup comparisons, mediation analyses, and subcortical atrophy-based subgroup analyses were performed to characterize disease-specific glymphatic-related impairment patterns. Results MS showed more extensive glymphatic-related impairment than NMOSD, with significant reductions in both DTI-ALPS and PVeD compared to HC (all p Conclusion Glymphatic-related dysfunction exhibits distinct disease-specific patterns in MS and NMOSD, with PVeD showing broader sensitivity across both cohorts. These findings support PVeD as a promising complementary glymphatic-related diffusion marker in inflammatory demyelinating disease, though causal and disease-mechanistic interpretations await validation in longitudinal and mechanistic studies.