FINGER COORDINATION IN ELDERLY

随着年龄的增长，手功能的损害是限制许多日常生活活动的主要致残因素。手灵巧度的下降可能导致独立性的丧失，在大多数日常活动中需要外部护理。我们目前对人类手的功能及其随年龄变化的理解是有限的。这使得有必要进行研究，以提高对手的功能及其随着年龄的增长而恶化的理解。一系列对照研究和对一小群老年受试者的初步研究结果使我们得以提出两个主要假设：(a)衰老与手部固有肌肉的选择性损伤有关；(b)衰老与多指任务时力量不足的增加有关。为了分析这些与年龄相关的变化对手灵巧度随年龄增长而丧失的可能贡献，我们详细阐述了以下研究计划：(1)使用更大的受试者群体和更广泛的任务来确认初步结论；(2)分析这些变化对多指协同作用的关键特征的影响，如次要力矩最小化和单个手指力的变异性模式（手指之间的误差补偿）；(3)分析在更常见的动作中手指和手的协调可能发生的变化，如抓握和双手处理物体；(4)手指协调性指标变化与涉及手功能的日常生活活动的相关性分析。在老年人和对照组中进行了七项实验，包括手指在抓握和按压任务中产生的力，自我施加的扰动和双手处理物体。该研究将结合无创行为、生物力学、电生理学和建模方法，以及问卷调查。在一个实验中，结果将与日常生活活动的指标进行比较。每个实验都做出了无法证明的预测。我们认为，支持或反驳这两个主要假设不仅对更好地理解与年龄相关的手部肌肉协调变化很重要，而且对开发新的手部功能康复方法也很重要。

Impairment of hand function with age is a major disabling factor limiting many activities of daily living. A decrease in the hand dexterity may lead to a loss of independence and require external care during most everyday activities. Our present understanding of the functioning of the human hand and changes in its function with age is limited. This makes it imperative to perform studies directed at improved understanding of the hand function and its deterioration with age. Series of studies on control subjects and preliminary findings in a small group of elderly subjects have allowed us to formulate two major hypotheses: (a) Aging is associated with selective impairment of intrinsic hand muscles; and (b) Aging is associated with an increase in force deficit during multi-finger tasks. The following research program has been elaborated for an analysis of possible contribution of these age-related changes to the loss of hand dexterity with age: (1) Confirmation of the preliminary conclusions using a larger subject population and a wider spectrum of tasks; (2) Analysis of the effects of these changes on crucial features of multi-finger synergies such as minimization of secondary moments and patterns of variability of individual finger forces (error compensation among fingers); (3) Analysis of possible changes in finger and hand coordination during more common actions such as gripping and bi-manual object handling; and (4) Analysis of correlations between changes in the indices of finger coordination and activities of daily living that involve hand function. Seven experiments on elderly and control subjects are suggested that include force production by sets of fingers in gripping and pressing tasks, self-imposed perturbations, and bi-manual object handling. The research will combine noninvasive behavioral, biomechanical, electrophysiological, and modeling methods, as well as questionnaires. In one experiment, the results will be compared with indices of the activities of daily living. Disprovable predictions are made for each experiment. We believe that supporting or disproving the two main Hypotheses is important not only for a better understanding of age-related changes in hand muscle coordination but also for development of new rehabilitation approaches to hand function.