To control hand movement, we have both vision and proprioception, or position sense. The brain is known to integrate these to reduce variance. Here we ask whether older adults integrate vision and proprioception in a way that minimizes variance as young adults do, and whether older subjects compensate for an imposed visuo-proprioceptive mismatch as young adults do. Ten healthy older adults (mean age 69) and 10 healthy younger adults (mean age 19) participated. Subjects were asked to estimate the position of visual, proprioceptive, and combined targets, with no direct vision of either hand. After a veridical baseline block, a spatial visuo-proprioceptive misalignment was gradually imposed by shifting the visual component forward from the proprioceptive component without the subject's awareness. Older subjects were more variable than young subjects at estimating both visual and proprioceptive target positions. Older subjects tended to rely more heavily on vision than proprioception compared to younger subjects. However, the weighting of vision vs. proprioception was correlated with minimum variance predictions for both older and younger adults, suggesting that variance-minimizing mechanisms are present to some degree in older adults. Visual and proprioceptive realignment were similar for young and older subjects in the misalignment block, suggesting older subjects are able to realign as much as young subjects. These results suggest that intact multisensory processing in older adults should be explored as a potential means of mitigating degradation in individual sensory systems.

中文翻译：

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老年人手的视觉本体控制。

为了控制手部运动，我们同时拥有视觉和本体感觉，或位置感。众所周知，大脑会整合这些以减少差异。在这里，我们询问老年人是否像年轻人一样以最小化方差的方式整合视觉和本体感觉，以及老年人是否像年轻人一样补偿强加的视觉-本体感觉不匹配。10 名健康老年人（平均年龄 69 岁）和 10 名健康年轻人（平均年龄 19 岁）参加。受试者被要求估计视觉、本体感觉和组合目标的位置，没有任何一只手的直接视觉。在一个真实的基线块之后，空间视觉本体错位是通过将视觉组件从本体感觉组件向前移动而在受试者没有意识的情况下逐渐施加的。在估计视觉和本体感觉目标位置时，老年受试者比年轻受试者更具可变性。与年轻受试者相比，老年受试者往往更依赖视觉而不是本体感觉。然而，视觉与本体感觉的权重与老年人和年轻人的最小方差预测相关，这表明老年人在某种程度上存在方差最小化机制。在错位块中，年轻和年长受试者的视觉和本体感觉重新调整是相似的，这表明年长受试者能够像年轻受试者一样重新调整。这些结果表明，应探索老年人完整的多感觉处理作为减轻个体感觉系统退化的潜在手段。