Shu-Han Yu1, Ing-Shiou Hwang2,3, Cheng-Ya Huang4. 1. Physical Therapy Center, National Taiwan University Hospital, Taipei, Taiwan. 2. Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. 3. Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan. 4. School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan.
Abstract
OBJECTIVES: Restricted central processing in older adults prevents optimization of a dual task with a flexible prioritization strategy. This study investigated the neural mechanisms of task-priority in young and older adults when performing a posture-motor dual-task. METHOD: Sixteen healthy young and 16 older adults performed a force-matching task on a mobile-platform under posture-focus (PF) and supraposture-focus (SF) conditions. The platform movement, force-matching performance, and event-related potentials in the preparatory period were recorded. RESULTS: For the elders, the postural stability and force-matching accuracy using the PF strategy were inferior to those using the SF strategy; whereas, the dual-task performances of the young adults were less affected by the prioritization. Only the elders exhibited the P1 wave, with the PF strategy associated with a smaller P1 and larger P1 than the SF strategy in the sensorimotor-parietal and right frontotemporal areas, respectively. The PF strategy also led to a larger P2 wave in the right frontotemporal area of elders, but a greater P2 wave in the sensorimotor-parietal area of young adults. DISCUSSION: For both prioritization strategies, older adults entailed a longer preparatory process than younger adults. Dual-task performance of older adults was more vulnerable to PF strategy, underlying compensatory resource allocation in the preparatory period for resolution of dual-task interference due to degenerated frontal function.
OBJECTIVES: Restricted central processing in older adults prevents optimization of a dual task with a flexible prioritization strategy. This study investigated the neural mechanisms of task-priority in young and older adults when performing a posture-motor dual-task. METHOD: Sixteen healthy young and 16 older adults performed a force-matching task on a mobile-platform under posture-focus (PF) and supraposture-focus (SF) conditions. The platform movement, force-matching performance, and event-related potentials in the preparatory period were recorded. RESULTS: For the elders, the postural stability and force-matching accuracy using the PF strategy were inferior to those using the SF strategy; whereas, the dual-task performances of the young adults were less affected by the prioritization. Only the elders exhibited the P1 wave, with the PF strategy associated with a smaller P1 and larger P1 than the SF strategy in the sensorimotor-parietal and right frontotemporal areas, respectively. The PF strategy also led to a larger P2 wave in the right frontotemporal area of elders, but a greater P2 wave in the sensorimotor-parietal area of young adults. DISCUSSION: For both prioritization strategies, older adults entailed a longer preparatory process than younger adults. Dual-task performance of older adults was more vulnerable to PF strategy, underlying compensatory resource allocation in the preparatory period for resolution of dual-task interference due to degenerated frontal function.