The Effects of Task Prioritization on Postural-suprapostural Task and Cortical Activity: Age-related Differences
Date Issued
2015
Date
2015
Author(s)
Yu, Shu-Han
Abstract
Background and Purpose: Postural-suprapostural task is defined as achievement of a motor or cognitive task performed simultaneously with successful postural control. Due to limited attentional resource, appropriate task prioritization is required for better performance during postural-suprapostural task, especially in elderly adults, who may have decreased attentional capacity and impaired attentional allocation. However, research on the suitable strategy of task prioritization (posture-first (PF) vs. supraposture-first (SF)) in younger and older adults is limited and lacks direct neural evidences. The purpose of this study was to investigate the effects of task-priority strategies on postural-suprapostural performance and its related cortical activity in younger and older populations. Methods: Sixteen younger healthy and sixteen elderly healthy adults were recruited in this study. Each participant was requested to perform a force-matching precision grip task (suprapostural task) while maintaining balance on a stabilometer (postural task) with postural task or suprapostural task as the first-priority task. Both behavioral and cortical data, including task accuracy (postural error and force-matching error), postural ApEn (approximate entropy), reaction time of precision-grip, and event-related potentials (ERPs), including P1, N1, and P2 amplitudes, were recorded. Results and Discussions: With SF strategy, less postural error was found in both younger and older groups. Furthermore, smaller force-matching error and larger postural ApEn were observed under the SF condition in the older group. ERP results revealed a task priority-dependent N1 response, which was smaller in the SF condition, indicating that SF is an efficient strategy for postural-suprapostural control. In addition, besides N1 and P2 waves, P1 positivity was observed only in the older adults, implying more facilitation of sensory processing was invested in the initial preparation phase of postural-suprapostural performance for older adults. Conclusion: SF strategy may be the adequate strategy for both healthy younger and older adults, with better postural-suprapostural accuracy and more efficient attentional allocation than PF strategy. Further study is needed to be confident in this conclusion for patients with neurological disease, such as Parkinson’s disease. Significance and Contribution: The study not only provided an optimal task-priority strategy for healthy adults, especially older adults, to increase their movement quality of postural-suprapostural task, but also gain a better insight to neural correlates of concurrent postural and motor-suprapostural tasks.
Subjects
task prioritization
postural balance
dual task
event-related potential
age effect
Type
thesis
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