Comparison of the Effects of Vestibular Rehabilitation and Dual-Task Exercise Programs on Cognitive and Motor Functions in Individuals With Parkinson's Disease

Parkinson's disease (PD) is a chronic, progressive neurodegenerative disorder characterized by motor symptoms such as tremor, rigidity, bradykinesia, and postural instability, as well as non-motor symptoms including cognitive impairment and depression. Postural control depends on the integration of visual, somatosensory, and vestibular inputs, and this multisensory integration is often impaired in PD. Vestibular dysfunction can manifest as dizziness, imbalance, and spatial disorientation, leading to functional limitations, an increased risk of falls, and reduced independence. Moreover, the vestibular system is anatomically and functionally connected to brain regions involved in cognition, such as the hippocampus and frontal cortex. Therefore, targeting vestibular function in rehabilitation may improve not only balance but also cognitive performance.

Previous research has demonstrated that vestibular rehabilitation can improve balance, gait, and postural stability in individuals with PD. However, its potential effects on cognitive functions have been largely neglected. In parallel, dual-task training-based on the simultaneous performance of motor and cognitive tasks-has emerged as an evidence-based approach to improve both motor and cognitive outcomes. Studies have shown that dual-task exercise can enhance gait speed, step length, balance, attention, and executive function in PD. Nevertheless, no studies have directly compared the effects of vestibular rehabilitation and dual-task exercise training on cognitive and motor functions in this population.

The present study is designed to fill this gap by comparing these two rehabilitation approaches. A total of 36 participants diagnosed with PD will be recruited and randomly assigned into three groups: (1) vestibular rehabilitation, (2) cognitive-motor dual-task training, and (3) control. Each intervention will be administered twice weekly for eight weeks, with each session lasting approximately 40 minutes under the supervision of a physiotherapist. The vestibular rehabilitation program will include static and dynamic balance training, gaze stabilization, adaptation, habituation, and substitution exercises. The dual-task training program will integrate functional balance exercises with concurrent cognitive challenges (e.g., counting backward, naming tasks, or alternating verbal tasks). The control group will maintain their usual level of physical activity.

Assessments will be conducted before and after the 8-week intervention. Cognitive functions will be evaluated using the Digit Span Test, Word Fluency Test, and Clock Drawing Test. Motor functions will be assessed with the Mini-BESTest, Four Square Step Test, and Dynamic Gait Index, along with postural stability analysis using KFORCE Plates. Activity and participation will be evaluated using the Parkinson's Activity Scale and the Parkinson's Disease Questionnaire (PDQ-39).

Data will be analyzed using SPSS 21.0. Depending on normality assumptions, repeated-measures ANOVA or non-parametric alternatives will be used to assess within- and between-group differences. Statistical significance will be set at p < 0.05.