Deep brain stimulation beyond Motor control: A systematic review and meta-analysis of sleep outcomes in Parkinson's...

Deep brain stimulation (DBS) has been a major advancement in treating movement disorders, yet its influence on sleep architecture remains unexplored. This systematic review evaluates the seven studies that have reported the objective polysomnography-based sleep parameters following DBS. A comprehensive literature search was made through PubMed, Cochrane, Embase, and Scopus from inception to November 30th, 2025, for studies reporting the pre- and post-DBS scores on polysomnography-based sleep outcomes. Random-effects models were utilized for the evaluation of REM, NREM, and sleep continuity/fragmentation parameters with heterogeneity assessed using the Q statistic and I². Pooled analysis revealed REM-related measures significantly improved by DBS, such as lower REM latency (95% CI: 1.669 to -0.092; p = 0.029), longer REM minutes (95% CI: 0.180 to 0.753; p = 0.001), and greater REM percentage (95% CI: 0.084 to 0.740; p = 0.014) accompanied by a diminishment of wake after sleep onset (WASO) (95% CI: 1.486 to -0.088; p = 0.027). Periodic limb movements approached statistical significance (p = 0.059) while the measures for the stages of NREM sleep and total sleep time were significantly unchanged. We interpret these results as evidence that DBS preferentially improves REM sleep measures and sleep continuity but indicates increments in sleep quality rather than the duration of sleep. Despite considerable heterogeneity, publication bias, and sensitivity to individual studies rendering these conclusions tenuous, larger multicenter studies incorporating standardized reporting and long-term follow-up are justified in order to confirm the longitudinal effects of DBS for sleep measures in PD.