Investigation of Upper Extremity Skills, Trunk Control, and Body Awareness in Individuals With Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by degeneration of dopaminergic neurons and the presence of both motor and non-motor symptoms. In addition to the cardinal motor features of tremor, rigidity, bradykinesia, and postural instability, individuals with PD commonly experience impairments in upper extremity function that negatively affect daily activities and participation. Difficulties in hand strength, manual dexterity, reaction time, movement speed, and upper limb coordination may interfere with reaching, grasping, object manipulation, and fine motor tasks.

Upper extremity performance in PD is influenced by several factors beyond the primary motor symptoms. Trunk control provides proximal stability required for efficient upper limb movement and functional task performance. Deficits in postural control, trunk mobility, and postural alignment may therefore contribute to upper extremity limitations. In addition, body awareness, defined as the perception and interpretation of bodily sensations, movements, and physical changes, has received increasing attention in neurological rehabilitation. Altered sensory integration, impaired kinesthetic processing, and movement-related difficulties observed in PD may affect body awareness and subsequently influence motor performance.

Although upper extremity dysfunction has been widely investigated in Parkinson's disease, the combined examination of upper extremity skills, trunk control, and body awareness remains limited. Furthermore, studies investigating body awareness in individuals with PD are scarce, and the relationship between body awareness and upper extremity performance has not been sufficiently explored.

The primary aim of this study is to investigate upper extremity skills, trunk control, and body awareness in individuals with Parkinson's disease and compare these characteristics with those of healthy adults. The secondary aim is to examine the relationships among upper extremity performance, trunk control, and body awareness within the Parkinson's disease group.

This study is designed as a cross-sectional observational study and does not include any intervention. A total of 118 participants will be recruited, including 59 individuals diagnosed with idiopathic Parkinson's disease and 59 age- and sex-matched healthy adults. Participants with Parkinson's disease will be evaluated during their medication "on" period. All assessments will be completed in a single session.