Rapid grip force responses to unexpected pulling loads on the fingertips are deteriorated in older adults due to, in part, age-related declines in somatosensory function. Such reports are limited to one-hand conditions despite the higher frequency of using two hands together in daily living activities of older adults. Unexpected perturbations during bimanual movements elicit goal-oriented and cortically-meditated bilateral rapid motor responses. Since aging is associated with declined somatosensory and cognitive functions, we hypothesized that bilateral rapid motor responses differ between young and older adults, such that older adults exert stronger grip forces following perturbation and the unperturbed hand is more involved in stabilizing the object in older adults. We tested our hypothesis by comparing the rapid grip force responses of both hands in young and older adults. A total of 13 right-handed young individuals (24.2 ± 4.0 years old, 5 men) and 13 right-handed older individuals (68.7 ± 7.1 years old, 5 men) were recruited. Tactile detection threshold, fingertip friction, and the rapid grip force responses of both hands triggered by unpredicted pulling loads during grip-lift movements were assessed. Older adults had higher tactile detection thresholds and lower fingertip friction compared to young adults. Regardless of age, rapid motor responses were found in both the perturbed (right) hand and the indirectly perturbed (left) hand at 73 ms and 135 ms after the perturbation, respectively, while magnitudes of the responses depended on perturbation magnitudes. Higher values in maximum grip force and maximum grip force rate were found in older adults as compared to young adults. In older adults, the indirectly perturbed (left) hand was more involved in stabilizing the object as compared to young healthy adults. The current study suggests that age-related changes in the peripheral and central nervous systems contribute to the greater involvement of the indirectly perturbed hand in older adults.

老年人对指尖意外拉力的快速握力反应会恶化，部分原因是与年龄相关的体感功能下降。尽管老年人在日常生活活动中同时使用两只手的频率较高，但此类报告仅限于单手情况。双手运动期间的意外扰动会引发目标导向和皮质冥想的双侧快速运动反应。由于衰老与体感和认知功能下降有关，我们假设年轻人和老年人之间的双侧快速运动反应不同，因此老年人在受到干扰后会施加更强的握力，而不受干扰的手更多地参与稳定老年人的物体。我们通过比较年轻人和老年人双手的快速握力反应来检验我们的假设。总共招募了 13 名右手年轻人（24.2 ± 4.0 岁，5 名男性）和 13 名右手老年人（68.7 ± 7.1 岁，5 名男性）。评估了触觉检测阈值、指尖摩擦力以及在握力提升运动期间由不可预测的拉力负载触发的双手的快速握力响应。与年轻人相比，老年人的触觉检测阈值更高，指尖摩擦力更低。无论年龄大小，受扰动（右）手和间接扰动（左）手分别在扰动后 73 毫秒和 135 毫秒时发现快速运动反应，而反应的幅度取决于扰动幅度。与年轻人相比，老年人的最大握力和最大握力率值更高。与年轻健康成年人相比，老年人的间接扰动（左手）更多地参与稳定物体。目前的研究表明，周围和中枢神经系统与年龄相关的变化导致老年人更多地参与间接受到干扰的手。