Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32611-8205, USA.
Exp Brain Res. 2010 Oct;206(3):319-27. doi: 10.1007/s00221-010-2411-3. Epub 2010 Sep 18.
Aging impairs the control of many skilled movements including speech. The purpose of this paper was to investigate whether young and older adults adapt to lower lip perturbations during speech differently. Twenty men (10 young, 26 ± 3 years of age; 10 older, 60 ± 9 years of age) were requested to repeat the word ("papa") 300 times. In 15% of the trials, the subjects experienced a mechanical perturbation on the lower lip. Displacement and neural activation (EMG) of the upper and lower lips were evaluated. Perturbations to the lower lip caused a greater increase in the maximum displacement of the lower lip for older adults compared with young adults (34.7 ± 19% vs. 13.4 ± 17%; P=0.017). Furthermore, young adults exhibited significantly greater 30-100 Hz normalized EMG power for the lower lip compared to the upper lip (P<0.005). In young adults, changes from normal to perturbed trials in the 30-50 Hz frequency band of the EMG were negatively correlated to the changes from normal to perturbed trials in the lower lip maximum displacement (R (2) =0.48; P=0.025). It is concluded that young adults adapt better to lower lip perturbations compared with older adults and that the associated neural activation strategy of the involved muscle is different for the two age groups.
衰老会损害许多熟练动作的控制能力，包括言语。本文旨在研究年轻人和老年人在言语时对下唇扰动的适应能力是否不同。要求 20 名男性（10 名年轻人，26 ± 3 岁；10 名老年人，60 ± 9 岁）重复单词“papa”300 次。在 15%的试验中，受试者下唇受到机械扰动。评估了上下唇的位移和神经激活（EMG）。与年轻人相比，老年人下唇的最大位移增加更大（34.7 ± 19%对 13.4 ± 17%；P=0.017）。此外，与上唇相比，年轻人下唇的 30-100 Hz 归一化 EMG 功率显著更大（P<0.005）。在年轻人中，从正常到扰动试验的 EMG 在 30-50 Hz 频带中的变化与从正常到扰动试验的下唇最大位移的变化呈负相关（R (2) =0.48；P=0.025）。结论是，与老年人相比，年轻人对下唇扰动的适应能力更好，并且两个年龄组涉及的肌肉的相关神经激活策略不同。
