Parkinson's disease (PD) is a neurodegenerative disease that affects about 1% of the elderly population and accounts for substantial disability and health care costs.

Disability is largely driven by mobility deficits caused by impaired gait. Effective treatments are available to restore lower limb function and improve gait, but response to treatment varies greatly from patient to patient and often shows only small effect sizes. Addressing this heterogeneity requires personalization, a concept referred to precision neurorehabilitation.

StimuLOOP.PD intends to foster structured and reproducible methods for precision neurorehabilitation of gait in PD. The investigator will conduct a proof-of-concept study to investigate a combination of two methods that are each tailored to the individual patient. Two innovative technologies are applied in concert to enhance recovery of lower limb function.

1. Hyper-personalized feedback (HPF): For lower limb motor rehabilitation, the investigator will employ real-time continuous feedback for movement aspects that are specific to each participant's motor deficit. The feedback will be adapted and tailored to each participant. This results in a two-step personalization; in a first step, the investigator will choose what movement aspect is therapeutically targeted, and in a second step, the investigator will define how the feedback is presented to the participant.
2. Targeted auditory stimulation during sleep (TASS):The investigator aim to reactivate rehabilitation- related memories through the presentation of auditory stimuli during sleep with the goal of promoting motor memory consolidation into stable motor commands.

The HPF intervention is expected to induce rapid adaptations, which however do not persist over multiple days. To counter this, the investigator will leverage memory reactivation during sleep to enhance the consolidation of the movement patterns that are learned during HPF.

The investigator expect that these interventions will lead to greater gains in functional walking ability. Beyond demonstrating a proof-of-concept for novel methods of precision neurorehabilitation, positive results of this project may have implications for neurorehabilitation treatment in general by providing first insights into the benefits and interplay of HPF and TASS.

Inclusion Criteria:

• Idiopathic Parkinson's disease with gait and postural stability deficits
• ≥18 years of age
• United Parkinson Disease Rating Scale (UPDRS) III gait scores 1-3
• UPDRS III postural instability scores 1-3
• Prescribed rehabilitation therapy at cereneo
• Informed consent as documented by signature
• Adjustments in dopaminergic medication and deep brain stimulation (DBS) to improve motor symptoms implemented to the current best possible extent

Exclusion Criteria:

• Cognitive impairment, Montreal Cognitive Assessment (MoCa) < 20
• Comprehensive aphasia precluding the understanding of study-related information
• Other neurological or medical condition that caused sustained clinically relevant gait and/or postural stability deficits
• Expected acute hospitalization during the training period
• History of a physical or neurological condition that interferes with study procedures
• Social and/or personal circumstances that interfere with the ability to return for therapy sessions and follow-up assessments
• Not capable of voluntary gait adaptation
• Patients taking benzodiazepines or Z-drugs that have a significant effect on sleep EEG
• Recent DBS implant (≤ 6 months)
• Inability to perform outcome assessments without walking aid
• Skin disorders/problems/allergies in face/ear area that could worsen with electrode application (e.g. nickel allergy)

Quadruple (participant, care provider, investigator, outcomes assessor).