Deficits in the production of grip forces in Down syndrome.

Down syndrome (DS) and control individuals were examined as to their ability to adapt grip forces to changes in the properties of lifted objects. The DS group generated substantially greater grip forces than the controls in all tests and failed to adapt normally to changes in the frictional properties of the objects. Their greater grip forces were not due to greater slipperiness of the skin of their fingers. These results are consistent with other findings of subtle deficits in DS individuals' use of somatosensory information for controlling movement and posture.