Coordination of prehensile forces during precision grip in Huntington's disease

The present study examined the coordination of prehensile forces during pre cision grip in subjects with Huntington's disease (HD). Fingertip forces we re measured in 12 subjects with HD and 12 age-matched controls during the l ifting of an instrumented object whose weight and surface texture were vari ed. The results indicate that subjects with HD have impaired initiation and delayed transitions between movement sequences and produce excessive and v ariable forces. However, subjects with HD demonstrated anticipatory scaling of force development based on the object's expected physical properties (p lanning) and adjustment of the force to the object's actual physical proper ties (sensorimotor integration). The observed findings generally were unrel ated to the overall disease severity. However, the variability in forces wa s correlated with functional capacity and motor performance suggesting that variability is a key feature of the motor deficit. These results provide i nsights into the impaired hand function observed in individuals with HD. (C ) 2000 Academic Press.