Effects and Mechanisms of RAS Training on Upper-limb Movements in PD Patients

Effects and Neural Mechanisms of Training Involving Rhythmic Auditory Stimulation on Upper-limb Movements in Patients With Parkinson's Disease

Introduction Bradykinesia (i.e., slow movements) is one of the most prominent symptoms of Parkinson's disease (PD) and has a negative impact on quality of life. Rhythmic auditory stimulation (RAS), a widely used and promising treatment technique, has been shown to effectively improve gait speed in PD patients. However, only few studies have explored effects and neural mechanisms of RAS on upper-limb movements. We will conduct two studies to investigate effects and mechanisms of RAS on upper-limb movements in PD patients. The purpose of this study is to examine effects and neural mechanisms of upper-limb movement training involving RAS in PD patients.

Methods This study will recruit patients with PD and healthy controls. This study will randomly assign PD patients into two groups: the PD-RAS group and the PD-noRAS group, and healthy controls into the HC-RAS group and the HC-noRAS group. A 7-day upper-limb training involving RAS (for the PD-RAS group and the HC-RAS group) or without RAS (for the PD-noRAS group and the HC-noRAS group) will be provided. EEG and behavioral assessments will be conducted before and after the first day of training, and after the seven-day training program. Two-way repeated measures analysis of variance will be performed to investigate the group and time effects on upper-limb function and neural activity.

Study significance The training program will serve as a reference for clinical practitioners who are interested in using RAS in clinical training for PD patients.

Inclusion Criteria:

• (a) idiopathic PD diagnosed by a neurologist based on the Movement Disorders Society clinical diagnostic criteria;
• (b) the Hoehn and Yahr stage is 2 or 3, meaning that bilateral movement problems or combination with mild postural instability;
• (c) a score of Montreal Cognitive Assessment (MoCA) is equal to or higher than 21 to ensure that they understand experimental instructions;
• (d) a score of Edinburgh Handedness Inventory is above 60 to ensure that they are right-handed;
• (e) types and doses of medications remain unchanged in the past month right before participation.
• Age- and sex-matched healthy controls who filled the criteria (c) and (d) will be recruited from communities.

Exclusion Criteria:

• the presence of medical conditions or diseases that may affect hand movements, vision, or hearing based on self-report.