Tamaru Yoshiki, Naito Yasuo, Nishikawa Takashi
Faculty of Rehabilitation, Shijonawate Gakuen University, Osaka, Japan.
Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Osaka, Japan.
Psychogeriatrics. 2017 Nov;17(6):382-388. doi: 10.1111/psyg.12256. Epub 2017 Mar 9.
Elderly people are less able to manipulate objects skilfully than young adults. Although previous studies have examined age-related deterioration of hand movements with a focus on the phase after grasping objects, the changes in the reaching phase have not been studied thus far. We aimed to examine whether changes in hand shape patterns during the reaching phase of grasping movements differ between young adults and the elderly.
Ten healthy elderly adults and 10 healthy young adults were examined using the Simple Test for Evaluating Hand Functions and kinetic analysis of hand pre-shaping reach-to-grasp tasks. The results were then compared between the two groups. For kinetic analysis, we measured the time of peak tangential velocity of the wrist and the inter-fingertip distance (the distance between the tips of the thumb and index finger) at different time points.
The results showed that the elderly group's performance on the Simple Test for Evaluating Hand Functions was significantly lower than that of the young adult group, irrespective of whether the dominant or non-dominant hand was used, indicating deterioration of hand movement in the elderly. The peak tangential velocity of the wrist in either hand appeared significantly earlier in the elderly group than in the young adult group. The elderly group also showed larger inter-fingertip distances with arch-like fingertip trajectories compared to the young adult group for all object sizes.
To perform accurate prehension, elderly people have an earlier peak tangential velocity point than young adults. This allows for a longer adjustment time for reaching and grasping movements and for reducing errors in object prehension by opening the hand and fingers wider. Elderly individuals gradually modify their strategy based on previous successes and failures during daily living to compensate for their decline in dexterity and operational capabilities.
老年人熟练操作物体的能力不如年轻人。尽管先前的研究已经关注抓握物体后阶段与年龄相关的手部运动退化，但迄今为止尚未研究伸手阶段的变化。我们旨在研究年轻人和老年人在抓握动作伸手阶段手部形状模式的变化是否存在差异。
使用手部功能简易测试和手部预塑形抓握任务的动力学分析，对10名健康老年人和10名健康年轻人进行了检查。然后比较两组的结果。对于动力学分析，我们测量了手腕切向速度峰值的时间以及不同时间点的指尖间距（拇指和食指指尖之间的距离）。
结果表明，无论使用优势手还是非优势手，老年人组在手部功能简易测试中的表现均显著低于年轻人组，这表明老年人的手部运动退化。老年人组两只手中手腕的切向速度峰值均比年轻人组出现得更早。与年轻人组相比，对于所有物体尺寸，老年人组还表现出更大的指尖间距和呈拱形的指尖轨迹。
为了进行精确抓握，老年人的切向速度峰值点比年轻人更早。这使得伸手和抓握动作有更长的调整时间，并且通过更宽地张开手和手指来减少物体抓握中的误差。老年人在日常生活中会根据先前的成功和失败逐渐调整他们的策略，以弥补其灵活性和操作能力的下降。
