Effects of Subthalamic Nucleus Deep Brain Stimulation on Sleep Quality and Daytime Sleepiness in Parkinson’s Disease: a Systematic Review and Meta‑analysis

BACKGROUND:Subthalamic nucleus deep brain stimulation (STN-DBS) is an established treatment for motor symptoms in Parkinson's disease (PD), but its effects on sleep remain uncertain. This study evaluated changes in nocturnal sleep quality and daytime sleepiness following STN-DBS. METHODS:Four databases were searched for longitudinal studies assessing sleep outcomes after STN-DBS in PD. Sleep was evaluated using the Parkinson's Disease Sleep Scale (PDSS) and Epworth Sleepiness Scale (ESS). Study quality was assessed with the Newcastle-Ottawa Scale. Pooled mean differences (MDs) were calculated using inverse-variance fixed-effects models, and heterogeneity was assessed with I2 statistics. RESULTS:Nine studies reporting PDSS outcomes (n = 286) and eight reporting ESS outcomes (n = 190) were included. Most patients underwent bilateral STN-DBS (93.7%). Pooled analyses demonstrated significant improvements in PDSS scores (MD 21.23 points, 95% CI 11.59-30.87; p < 0.01) and reductions in ESS scores (MD - 3.62 points, 95% CI - 5.09 to -2.14; p < 0.01). Heterogeneity was negligible for both outcomes (τ = 0; I2 = 0%). The 95% prediction intervals remained favorable for PDSS (9.61-32.86) and ESS (-5.46 to -1.77), suggesting consistent findings across studies. CONCLUSION:Current evidence suggests that STN-DBS is associated with improved subjective sleep quality and reduced daytime sleepiness in patients with PD. However, these findings should be interpreted cautiously because they are derived primarily from observational studies with limited sample sizes and potential confounding factors. Prospective studies specifically designed to evaluate sleep outcomes are needed to clarify the independent effects of STN-DBS on sleep.