Effects of deep brain stimulation on sleep-wake disturbances in patients with Parkinson's disease: A narrative review.

Sleep-wake disturbances (SWD) are one of the most common non-motor symptoms in Parkinson's disease (PD) and can appear in the early stage even before the onset of motor symptoms. Deep brain stimulation (DBS) is an established treatment for the motor symptoms in patients with advanced PD. However, the effect of DBS on SWD and its specific mechanisms are not widely understood and remain controversial. In addition to the circuit-mediated direct effect, DBS may improve SWD by an indirect effect such as the resolution of nocturnal motor complications and a reduction of dopaminergic medication. Here, the authors review the recent literatures regarding the impact of DBS on SWD in patients with PD. Furthermore, the selection of the DBS targets and the specific effects of applying DBS to each target on SWD in PD are also discussed.