School of Rehabilitation Sciences, Old Dominion University, Norfolk, VA, USA.
Department of Exercise and Sport Science, University of North Carolina At Chapel Hill, Chapel Hill, USA.
Exp Brain Res. 2020 Mar;238(3):565-574. doi: 10.1007/s00221-020-05736-8. Epub 2020 Jan 29.
Aging is associated with physiological changes which can manifest as age-related slowing of voluntary movements. Dual-task conditions can magnify this slowing process in older adults. The current study describes healthy adult chewing patterns and examined effects of concurrent chewing on performance of simple reaction time (RT), finger tapping, and gait. Chewing rates were measured from electromyographic (EMG) activity from the masseter muscle. Stepping rates were calculated using accelerometers mounted on the lower trunk and leg. Tapping rates were collected using accelerometers secured to a fixed surface. Simple RT was attained from a purposely designed switch. Results demonstrated that older adults walked slower, tapped slower, and had slower reaction times compared to young individuals, however chew rates were similar. This dichotomy became more pronounced when motor tasks were performed at faster speeds, with the exception being chewing. Additionally, chewing altered performance of secondary motor tasks for all individuals. Strong coupling emerged between cyclical actions (i.e., chewing-gait and chewing-tapping), reflecting entrainment between the respective neural oscillators driving the actions. In contrast, RT responses slowed appreciably when chewing was performed concurrently, indicating an interference effect. Taken together, these results illustrate the contrasting effects of chewing on a secondary motor task and highlights bidirectional effects of dual tasking on performance.
衰老是与生理变化相关的，这些变化可能表现为与年龄相关的自愿运动速度减慢。双重任务条件会使老年人的这种减速过程放大。本研究描述了健康成年人的咀嚼模式，并研究了同时咀嚼对简单反应时间（RT）、手指敲击和步态的性能的影响。咀嚼率是从咀嚼肌的肌电图（EMG）活动中测量的。加速度计安装在下躯干和腿部来计算步速。使用固定在表面上的加速度计收集敲击率。简单 RT 通过专门设计的开关获得。结果表明，与年轻人相比，老年人的步行速度较慢，敲击速度较慢，反应时间也较慢，但咀嚼速度相似。当执行更快的运动任务时，这种二分法变得更加明显，除了咀嚼。此外，咀嚼会改变所有个体的次要运动任务的性能。周期性动作（即咀嚼-步态和咀嚼-敲击）之间出现了强耦合，反映了驱动动作的相应神经振荡器之间的同步。相比之下，当同时进行咀嚼时，RT 反应明显减慢，表明存在干扰效应。总之，这些结果说明了咀嚼对次要运动任务的影响是相反的，并强调了双重任务对性能的双向影响。
