Quantification of hand grasp force using a pressure mapping system.

The goal of this study was to use a pressure sensor to measure the force distribution and contact area of the hand when gripping, pushing, and pulling a cylinder. Data was collected from 10 subjects with no hand impairments and from 1 subject with rheumatoid arthritis (RA). Subjects grasped an aluminum cylinder wrapped with a Tekscan pressure sensor and performed each trial at 25%, 50%, and 100% maximum voluntary exertion. A relationship was found between increasing exertion and increasing hand area with increasing hand contact area. The force distribution maps showed the thenar region of the hand exerts the most force during pushing while the metacarpal joint line exerts the highest force during pulling. The third and fourth phalange were found to exert the highest phalange force during gripping. The force distribution maps from the RA subject showed higher thumb forces and distal phalange forces, relative to the entire phalange, compared to the non-impaired subjects. This suggests that the RA subject compensates for the lack of phalange function with the regions of the hand that still function. Future studies should sample individuals with a larger hand area range and sample more individuals with RA.