Changes in finger coordination and hand function with advanced age

Summary: Age-related changes in the hand neuromuscular apparatus are accompanied by changes in both finger strength and finger coordination. The loss of strength is more pronounced during maximal torque production tasks than in maximal force production tasks. Intrinsic hand muscles show a disproportionate loss of force, which may render multi-digit synergies learnt over the lifetime suboptimal. Age leads to lower force production by uninstructed fingers (lower enslaving), which may have negative effects on performance in tasks that involve rotational equilibrium constraints. Elderly persons show worse stabilization of the total force during accurate force production tasks (the stabilization is achieved by co-variation of forces produced by individual digits). They also show worse stabilization of the total moment produced on a hand-held object as compared to young persons. Some of the age-related changes, such as higher safety margins and higher antagonist moments produced by finger forces, may be viewed as adaptive. Other changes, however, are likely to interfere with the everyday hand function making it suboptimal.