Department of Physical Medicine and Rehabilitation, Albert Einstein College of Medicine, Yeshiva University, 1165 Morris Park Avenue, Room 338, Bronx, NY 10461, USA.
Aging Clin Exp Res. 2013 Apr;25(1):99-106. doi: 10.1007/s40520-013-0014-0. Epub 2013 Mar 27.
Performing multiple tasks simultaneously may result in reduced performance of subtasks (dual-task cost) particularly among old individuals. Subtask performance during dual tasking is also known to be affected by task prioritization. However, it has not been well studied how the performance of subtasks is affected during motor dual task in old adults compared to young when instructed to prioritize one task over the other. This study aims to investigate the dual-task effect on subtasks during motor dual tasking under specific instruction of task prioritization in old compared to young adults.
Sixteen independent old and 18 young adults performed two single tasks (usual walking, holding a tray as steady as possible while standing) and two dual tasks (walking while holding a tray focusing attention on keeping tray as steady as possible-WTAT, and walking while holding tray focusing attention on walking-WTAW). Gait parameters [velocity and variability (coefficient of variation, CV) of stride length] and the pitch (forward-backward) and roll (side-to-side) angles of the tray were measured during the four conditions.
During the WTAT compared to single tasks, both young and old groups showed reduced gait velocity (β = -14.0 for old, -34.3 for young), increased gait variability (β = 0.19 for old, 0.51 for young), and increased tray tilt (β = 9.4 for old, 7.9 for young in pitch; β = 8.8 for old, 5.9 for young in roll). Higher proportion of older individuals showed higher dual-task effect on tray stability, but lower dual-task effect on gait compared to young individuals. During WTAW, there was no difference in dual-task effect between age groups in tray stability or gait performance.
Compared to young, older adults tend to compromise the task involving upper limbs during motor dual tasking even when instructed to prioritize this task over gait. These findings may have ramifications on developing training strategies to learn or relearn complex motor activities in seniors.
同时执行多项任务可能会导致子任务的表现下降（双重任务成本），尤其是在老年人中。在双重任务中，子任务的表现也受到任务优先级的影响。然而，与年轻人相比，当被指示优先考虑一项任务而不是另一项任务时，老年人在进行运动双重任务时，子任务的表现如何受到影响，这方面的研究还不够充分。本研究旨在调查在特定的任务优先级指导下，与年轻人相比，老年人在进行运动双重任务时对子任务的双重任务效应。
16 名独立的老年人和 18 名年轻人分别进行了两项单任务（正常行走、站立时尽可能稳定地端着托盘）和两项双重任务（行走时端着托盘，专注于保持托盘尽可能稳定-WTAT，行走时端着托盘，专注于行走-WTAW）。在四种情况下，测量步态参数（速度和步长变异系数，CV）和托盘的俯仰（前后）和滚动（左右）角度。
与单任务相比，WTAT 时，老年人和年轻人的步态速度均降低（β=-14.0，β=-34.3），步态变异性增加（β=0.19，β=0.51），托盘倾斜度增加（β=9.4，β=7.9，在俯仰方向；β=8.8，β=5.9，在滚动方向）。更多的老年人表现出更高的双重任务效应，对托盘稳定性的影响更大，而对步态的影响更小，与年轻人相比。在 WTAW 时，两组在托盘稳定性或步态表现方面，双重任务效应无差异。
与年轻人相比，老年人在进行运动双重任务时，即使被指示优先考虑这项任务而不是步态，也更倾向于放弃上肢任务。这些发现可能对制定培训策略以帮助老年人学习或重新学习复杂的运动活动具有重要意义。
