The study is a randomized, double-blind, sham-controlled cross-over trial to assess the efficacy as well as safety and tolerability of auditory SWS enhancement on measured outcomes in PD patients with disturbed nighttime sleep. Patients will be randomized to 2 groups: Group 1 will first be treated with auditory stimulation for 3 nights and then - after a wash-out period of 4 nights - switched to 3 nights of sham stimulation. Group 2 will first receive sham-stimulation for 3 nights and then switch to 3 nights of auditory stimulation treatment. The wash-out period in between will be 4 nights. Patients and investigators assessing the outcomes will be blinded to the conditions. All interventions will take place at the patients' homes.~The pilot study is aimed at assessment of safety, tolerability, feasibility and efficacy of auditory SWS enhancement on measured outcomes in MCI and HD patients with disturbed nighttime sleep. Patients will be treated with verum or sham auditory stimulation for 2 consecutive nights. All interventions will take place at the patients' homes.
The study is a randomized, double-blind, sham-controlled cross-over trial to assess the efficacy as well as safety and tolerability of auditory SWS enhancement on measured outcomes in Parkinson disease (PD) patients with disturbed nighttime sleep.~Additionally, the investigators will assess the feasibility and efficacy of auditory slow-wave sleep (SWS) enhancement in Mild Cognitive Impairment (MCI) and Huntington Disease (HD) patients in a pilot study.