GRASP FORCE CONTROL IN OLDER ADULTS
GRASP FORCE CONTROL IN OLDER ADULTS
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DOI：
10.1080/00222895.1991.9942036
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发表时间：
1991-12-01
影响因子：
1.4
通讯作者：
COLE, KJ
中科院分区：
文献类型：
--
作者：
COLE, KJ
据报道，老年人的触觉灵敏度下降，手部灵活性受损。有报告称，触觉严重受损的年轻人在常规抓握和操作任务中使用过度的抓握力，这可能导致老年人同样产生可能导致灵巧性受损的大抓握力。老年受试者也会出现出汗功能受损，可能会产生更光滑的皮肤表面，从而增加过度抓握力的可能性。本研究测量把握力在10个老年人和9个年轻的成年人，在把握和垂直升降机的一个小物体，使用精确（捏）握拇指和食指。物体表面的光滑度出乎意料地变化。皮肤光滑度也是通过测量物体从抓握中滑落时的抓握力来估计的。老年受试者使用的抓握力平均是年轻受试者的两倍，有些人产生的抓握力比年轻受试者的平均抓握力大很多倍。在老年受试者的试验中，握力的变化也显著更大。这种增加的变异性不仅仅是由老年受试者增加的握力引起的。一部分增加的力是由于皮肤光滑度增加。然而，老年受试者产生的超过滑动力（防止物体滑动的“安全裕度”）的抓握力大于从他们的皮肤光滑度预测的。有人建议，在某种程度上，过度的把握力量代表了触觉障碍的战略反应。老年受试者的两点辨别力阈值平均是年轻受试者的四倍。老年人抓握力的增加可能由其他因素引起，例如抓握力产生的可变性增加。过度的抓力对老年人灵活性受损的贡献仍然需要通过实验来解决。
Diminished tactile sensibility and impaired hand dexterity have been reported for elderly individuals. Reports that younger adults with severely impaired tactile sensibility use excessive grasp force during routine grasp and manipulation tasks raise the possibility that elderly persons likewise produce large grasp forces that may contribute to impaired dexterity. Impaired sudomotor functioning also occurs in elderly subjects and may yield a slipperier skin surface that enhances the possibility for excessive grasp force. The present study measured grasp force in 10 elderly and 9 young adult individuals, during grasp and vertical lift of a small object, using a precision (pinch) grip of the thumb and index finger. The slipperiness of the object's gripped surfaces was unexpectedly varied. Skin slipperiness was estimated by also measuring the grasp force at which the object slipped from grasp.The older subjects employed grasp forces that were, on average, twice as large as those of the young subjects, with some producing forces many times greater than the young subjects' average grip force. Grip forces also were significantly more variable across trials in older subjects. This increased variability was not caused simply by the elderly subjects' increased grip force. A portion of the increased force was due to increased skin slipperiness. The grip force that the elderly subjects produced in excess of the slip force (the "margin of safety" against object slippage) was larger than would have been predicted from their skin slipperiness, however. It is suggested that, in part, the excessive grasp forces represent a strategic response to tactile sensibility impairment. Two-point discrimination limina in the older subjects averaged about four times greater than in the younger subjects. Increased grasp forces in elderly persons may result from other factors, such as increased variability in grip force production. The contributions of excessive grasp forces to impaired dexterity in older persons still need to be addressed experimentally.