Motor and Cognitive Impairments in Parkinson Disease: Relationships With Specific Balance and Mobility Tasks

Background. Balance and mobility problems are common for people with Parkinson disease (PD). Objective. To determine the relationships of motor and cognitive impairments with specific balance and mobility task performance. Methods. A total of 82 community-dwelling people with idiopathic PD were tested on medication. Impairments measured included leg extensor and hip abductor muscle power, freezing of gait, dyskinesia, and executive function. Balance and mobility were classified into tasks requiring anticipatory control with a change in base of support, anticipatory control without a change in support, and reactive adjustments in response to external perturbations. Associations between impairments and tasks were examined using univariable and multivariable linear regression models. Results. Univariable models revealed that muscle power was significantly related to balance and mobility, explaining 7% to 33% of the variability in task performance. Freezing of gait, dyskinesia, and executive function were not consistently related to task performance. Multivariable models that included all impairments plus disease severity, age, gender, and height explained 5% to 43% of the variability in balance and mobility tasks. Leg muscle power was the only impairment with a consistent association with performance of tasks involving anticipatory control with a change in base of support (beta = 0.2 to 0.5), but the association of each muscle group was specific to individual tasks. Conclusion. Information gained from this study about the relationships between impairments and specific balance and mobility tasks may be able to guide the development of interventional strategies for people with PD.