Keenan Kevin G, Huddleston Wendy E, Ernest Bradley E
Department of Kinesiology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin; and
Center for Aging and Translational Research, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin.
J Neurophysiol. 2017 Nov 1;118(5):2537-2548. doi: 10.1152/jn.00928.2016. Epub 2017 Jul 12.
The purpose of the study was to determine the visual strategies used by older adults during a pinch grip task and to assess the relations between visual strategy, deficits in attention, and increased force fluctuations in older adults. Eye movements of 23 older adults (>65 yr) were monitored during a low-force pinch grip task while subjects viewed three common visual feedback displays. Performance on the Grooved Pegboard test and an attention task (which required no concurrent hand movements) was also measured. Visual strategies varied across subjects and depended on the type of visual feedback provided to the subjects. First, while viewing a high-gain compensatory feedback display (horizontal bar moving up and down with force), 9 of 23 older subjects adopted a strategy of performing saccades during the task, which resulted in 2.5 times greater force fluctuations in those that exhibited saccades compared with those who maintained fixation near the target line. Second, during pursuit feedback displays (force trace moving left to right across screen and up and down with force), all subjects exhibited multiple saccades, and increased force fluctuations were associated ( = 0.6; = 0.002) with fewer saccades during the pursuit task. Also, decreased low-frequency (<4 Hz) force fluctuations and Grooved Pegboard times were significantly related ( = 0.033 and = 0.005, respectively) with higher (i.e., better) attention scores. Comparison of these results with our previously published results in young subjects indicates that saccadic eye movements and attention are related to force control in older adults. The significant contributions of the study are the addition of eye movement data and an attention task to explain differences in hand motor control across different visual displays in older adults. Older participants used different visual strategies across varying feedback displays, and saccadic eye movements were related with motor performance. In addition, those older individuals with deficits in attention had impaired motor performance on two different hand motor control tasks, including the Grooved Pegboard test.
该研究的目的是确定老年人在捏握任务中使用的视觉策略，并评估视觉策略、注意力缺陷与老年人力量波动增加之间的关系。在低力度捏握任务期间，对23名老年人（>65岁）的眼球运动进行了监测，同时受试者观看三种常见的视觉反馈显示。还测量了他们在有槽钉板测试和一项注意力任务（该任务不需要同时进行手部动作）中的表现。视觉策略因受试者而异，并取决于提供给受试者的视觉反馈类型。首先，在观看高增益补偿性反馈显示（水平条随力量上下移动）时，23名老年受试者中有9名在任务期间采用了扫视策略，与那些在目标线附近保持注视的受试者相比，采用扫视策略的受试者力量波动大2.5倍。其次，在追踪反馈显示（力量轨迹在屏幕上从左到右移动，并随力量上下移动）期间，所有受试者都表现出多次扫视，并且在追踪任务期间力量波动增加与较少的扫视次数相关（r = 0.6；p = 0.002）。此外，较低频率（<4 Hz）的力量波动减少和有槽钉板测试时间与较高（即更好）的注意力得分显著相关（分别为r = 0.033和p = 0.005）。将这些结果与我们之前发表的关于年轻受试者的结果进行比较表明，扫视眼球运动和注意力与老年人的力量控制有关。该研究的重要贡献在于增加了眼球运动数据和一项注意力任务，以解释老年人在不同视觉显示下手部运动控制的差异。老年参与者在不同的反馈显示中使用了不同的视觉策略，并且扫视眼球运动与运动表现相关。此外，那些注意力有缺陷的老年人在两项不同的手部运动控制任务（包括有槽钉板测试）中运动表现受损。
