Grip force release is impaired in parkinson's disease during a force tracking task.

The controlled release of grasping forces underlies skilled dexterous interactions with objects. While declines in force generation and maintenance are well documented in people with Parkinson's disease (PwPD), limited data exist related to how PD impacts the motor control of grasping force release. The aim of this project was to determine how PD impacts grip force release relative to the generation and maintenance of force. It was hypothesized that PwPD would exhibit global deficits in force control relative to controls but would perform disproportionately worse during the controlled release of grip force. Ten PwPD and 10 age-matched controls completed a force-tracking paradigm requiring grip force generation, maintenance, and release. Compared to controls, PwPD were less accurate (i.e. less time within target range), had greater error (i.e. greater relative root mean squared error), and had more trial-to-trial variability in error during grip force release. Ongoing studies are examining the potential neural mechanism(s) underlying of force release impairments in PD, and the relationships between PD severity, manual dexterity, and force release declines.