Glymphatic dysfunction across sleep disorders: a meta-analysis of DTI-ALPS studies

Background: Sleep disorders are increasingly linked to glymphatic dysfunction, but whether this impairment is universal across different sleep pathologies remains unclear. Objective: This meta-analysis examined whether glymphatic dysfunction, assessed via the diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) index, may represent a shared neural feature across a spectrum of sleep disorders. Methods: We systematically searched PubMed, EMBASE, and the Cochrane Library from inception to December 31, 2025, for observational studies comparing DTI-ALPS index between patients with sleep disorders and healthy controls. Data were synthesized from 19 studies (n = 2,315) using a random-effects model to calculate standardized mean differences (SMDs). Methodological quality was assessed with the Newcastle-Ottawa Scale. Subgroup analyses, meta-regression, sensitivity analyses, and publication bias assessment were performed. Results: = 0.01). Conclusion: Glymphatic dysfunction, as assessed by DTI-ALPS, is consistently observed across several sleep disorders, suggesting a potential shared pathway. However, extreme heterogeneity limits interpretability of the pooled effect, and cross-sectional data preclude causal inference.