Kiani Kimia, Patel Maya, Fu Qiushi
Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL, United States.
Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States.
Front Aging Neurosci. 2025 Aug 6;17:1525535. doi: 10.3389/fnagi.2025.1525535. eCollection 2025.
Skilled bimanual coordination is an essential component of activities of daily living that relies on complex interactions between the limbs, yet how age-related changes impact asymmetries in visuomotor control during these tasks remains largely unknown. In the present study, we examined both motor performance and visual attention distribution in non-rhythmic continuous bimanual tasks and investigated the effect of aging.
Twelve right-handed young adults (YA) and twelve right-handed older adults (OA) performed a bimanual tracking task in which each hand controlled a cursor using a robotic device to track the upward movement of a horizontal target line simultaneously and independently. We assessed participants' performance in the symmetric condition, where both hands should perform the same actions to be successful. Additionally, participants performed the task in asymmetric conditions, where either a new force or a change in visuomotor gain was applied to only one hand, requiring participants to adapt by producing distinct actions with two hands. Overt visual attention was assessed by analyzing participants' gaze fixation patterns during successful task performance.
Our findings revealed that YA experienced greater difficulty with asymmetric visuomotor constraints than asymmetric force constraints, whereas OA showed comparable performance challenges with both types of constraints. Moreover, we found that YA distributed the gaze consistently biased to the right side despite the effect of context asymmetry on tracking errors, while OA distributed their gaze more symmetrically. Lastly, YA demonstrated asymmetrical adaptation, with improved performance in the dominant right hand under left-sided constraints, while OA showed reduced adaptation capabilities.
These findings indicate that aging is associated with a reduction in lateralized attention and diminished adaptability to asymmetric task demands during bimanual visuomotor coordination.
熟练的双手协调是日常生活活动的重要组成部分，它依赖于四肢之间复杂的相互作用，但与年龄相关的变化如何影响这些任务中视觉运动控制的不对称性，在很大程度上仍不为人知。在本研究中，我们考察了非节律性连续双手任务中的运动表现和视觉注意力分配，并研究了衰老的影响。
12名右利手年轻成年人（YA）和12名右利手老年人（OA）进行了一项双手跟踪任务，在该任务中，每只手使用机器人设备控制一个光标，以同时且独立地跟踪一条水平目标线的向上移动。我们评估了参与者在对称条件下的表现，在该条件下，双手需执行相同动作才能成功。此外，参与者在非对称条件下执行任务，在这种条件下，仅对一只手施加新的力或视觉运动增益的变化，这要求参与者通过双手产生不同动作来进行适应。通过分析参与者在成功完成任务期间的注视模式来评估外显视觉注意力。
我们的研究结果显示，如果视觉运动约束不对称，年轻成年人比力约束不对称时遇到的困难更大，而老年人在这两种约束条件下表现出相当的挑战。此外，我们发现，尽管情境不对称对跟踪误差有影响，但年轻成年人的注视始终偏向右侧，而老年人的注视分布更对称。最后，年轻成年人表现出不对称适应，在左侧约束下优势右手的表现有所改善，而老年人的适应能力则有所下降。
这些结果表明，在双手视觉运动协调过程中，衰老与侧向注意力的降低以及对不对称任务需求的适应能力减弱有关。
