Auditory Slow Wave Enhancement in Parkinson Disease and Mild Cognitive Impairment

Inclusion Criteria:

• PD: Diagnosis of PD along international criteria, with mild to moderate diseaseseverity (Hoehn and Yahr scale, stages ll-lll)
• PD: Ability to apply the intervention for the duration of study
• MCI: Diagnosis of MCI along international criteria, with a predominant amnesticpresentation (single- or multi-domain amnestic MCI)
• MCI: Presence of a cohabitant person who could assist with the application
• MCI: Ability to apply the intervention for the duration of study, with assistance ofco-habitant if needed PD and MCI:
• Age above 18 years
• Informed consent as documented by signature
• Stable home situation (e.g. long-term place to live) that allows for reliableapplication of intervention for the duration of the study
• Sufficient German language comprehension to follow the study procedures and answer allquestions related to the study outcomes
• Dosing of dopaminergic, cholinergic, and other PD or MCI medication must have beenstable for at least 14 days prior to start of the first intervention
• Negative pregnancy test during screening (except in women who are surgicallysterilized/hysterectomized or postmenopausal for longer than 1 year)

Exclusion Criteria:

• PD: Presence of neurologic, psychiatric, or sleep disorders (others than associatedwith PD)
• PD: Parkinsonism without response to levodopa; Atypical Parkinsonian syndromes
• PD: Cognitive impairment (Montréal Cognitive Assessment [MoCA] <24)
• MCI: Present diagnosis of a neurological (other than MCI) or interfering psychiatricdisease or sleep disorder (e.g. sleep apnoea syndrome, restless legs syndrome) PD and MCI:
• Severe medical conditions as renal insufficiency, liver failure or congestive heartfailure
• Regular use of the following drugs: Benzodiazepines and other central nervous system (CNS)-depressant substances, melatonin and other sleep inducing substances, approveddrugs for Alzheimer-type dementia (acetylcholine-esterase inhibitor, memantine)
• Inability to hear the tones produced by the TSB Axo
• Skin disorders/problems/allergies in face/ear area that could worsen with electrodeapplication
• Known or suspected drug- or medication abuse
• Known or suspected non-compliance
• Participation in another study with investigational drug or investigational medicaldevices within the 30 days preceding and during the present study
• Previous enrolment in the current study
• Enrolment of the investigator, his/her family members, employees and other dependentpersons
• Shift work (work during the night)
• Travelling more than 2 time zones in the last month before intervention starts orduring intervention (start of intervention will be adapted to fit with this criteria)
• Substance or alcohol abuse (i.e. > 0.5 l wine or 1 l beer per day)
• High caffeine consumption (> 5 servings/day; including coffee, energy drink)
• Implanted deep brain stimulation electrodes
• Women who are pregnant or breast feeding
• Intention to become pregnant during the course of the study
• Lack of safe contraception, defined as: Female patients of childbearing potential, notusing and not willing to continue using a medically reliable method of contraceptionfor the entire study duration, such as oral, injectable, or implantablecontraceptives, or intrauterine contraceptive devices, or who are not using any othermethod considered sufficiently reliable by the investigator in individual cases