Aging Alters the Sense of Force but Not the Sense of Position in the Wrist and Ankle Joints.

INTRODUCTION

The impact of aging on proprioceptive senses remains an open question. As the senses of position and force may rely on different neural substrates, we investigated the effect of aging on both senses to provide original and more comprehensive data on age-related changes in proprioception.

METHODS

The senses of position and force were assessed in several conditions using position- and force-reproduction tasks in young (20-40 years) and older (60-90 years) adults in the wrist (experiment 1, n = 41, 20 older adults) and ankle joints (experiment 2, n = 46, 24 older adults).

RESULTS

In both experiments, older adults exhibited larger force-reproduction errors than young adults at low (5% maximal force, p < 0.001) but not moderate forces (20% maximal force, p > 0.056). No age-related decline was observed for position-reproduction errors (p > 0.30), regardless of movement amplitude. Rare weak-to-moderate correlations were observed between position- and force-reproduction errors (r ≤ 0.53, p ≥ 0.009).

CONCLUSION

In wrist and ankle joints, the age-related decline in proprioception is limited to the sense of force, especially for low forces. This nonuniform decline in proprioception across proprioceptive senses and testing conditions could reflect a decline in the central processing of proprioceptive information.