Non-invasive brain stimulation to enhance sleep quality and architecture in Parkinson's disease: A systematic review and Bayesian network meta-analysis

Individuals with Parkinson's disease (PD) suffer from sleep disorders and maladaptive alterations in sleep architecture. These disorders, which increase in frequency and severity as the disease progresses, are multifactorial and clinically relevant. Sleep problems drastically reduce quality of life in these patients and are associated with faster cognitive and motor decline. Standard treatments for managing sleep disorders, which mainly include cognitive behavioral therapy and pharmacotherapy, have provided inconsistent results. Non-invasive brain stimulation (NIBS) has been proposed as another potential strategy for improving sleep quality in PD. We conducted a systematic review and Bayesian network meta-analysis (NMA) following the grading of recommendations, assessment, development, and evaluation (GRADE), to determine whether NIBS improves sleep quality and architecture in PD. Evidence from twenty-four studies, including 792 individuals with PD in the early-to-severe disease stages, was summarized. Our NMA indicated that low-frequency repetitive transcranial magnetic stimulation over the dorsolateral prefrontal cortex (rTMS; 0.54, 95 %CrI: 0.13,0.93; moderate certainty) may ameliorate subjective sleep quality compared to a control condition. Our review further suggested that rTMS may enhance objective sleep quality and sleep architecture. Our findings, which should be interpreted cautiously due to a high risk of bias, are examined in the context of sleep disorders in PD.