Steeve Roger W, Moore Christopher A, Green Jordan R, Reilly Kevin J, Ruark McMurtrey Jacki
Division of Communication Disorders, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, USA.
J Speech Lang Hear Res. 2008 Dec;51(6):1390-404. doi: 10.1044/1092-4388(2008/07-0046). Epub 2008 Jul 29.
The ontogeny of mandibular control is important for understanding the general neurophysiologic development for speech and alimentary behaviors. Prior investigations suggest that mandibular control is organized distinctively across speech and nonspeech tasks in 15-month-olds and adults and that, with development, these extant forms of motor control primarily undergo refinement and rescaling. The present investigation was designed to evaluate whether these coordinative infrastructures for alimentary behaviors and speech are evident during the earliest period of their co-occurrence.
Electromyographic (EMG) signals were obtained from the mandibular muscle groups of 15 typically developing 9-month-old children during sucking, chewing, and speech.
Unlike prior investigations of 12- and 15-month-olds and adults, 9-month-olds' analyses of peak correlations among agonist and antagonist comparisons of mandibular EMG data revealed weak coupling during sucking, chewing, and babble; associated lag values for antagonist muscle groups indicated greater synchrony during alimentary behaviors and less synchrony during babble. Unlike the speech data of 15-month-olds, 9-month-olds exhibited consistent results across speech subtasks.
These findings were consistent with previous results in which mandibular coordination across behaviors was more variable for younger age groups, whereas the essential organization of each behavior closely reflected that seen in older infants and adults.
下颌控制的个体发生对于理解言语和进食行为的一般神经生理发育很重要。先前的研究表明，15个月大的婴儿和成年人在下颌控制在言语和非言语任务中的组织方式有所不同，并且随着发育，这些现有的运动控制形式主要经历细化和重新调整。本研究旨在评估这些用于进食行为和言语的协调基础结构在它们同时出现的最早阶段是否明显。
在吮吸、咀嚼和言语过程中，从15名发育正常的9个月大儿童的下颌肌群获取肌电图（EMG）信号。
与先前对12个月和15个月大婴儿及成年人的研究不同，对9个月大婴儿下颌肌电图数据的激动剂和拮抗剂比较中的峰值相关性分析显示，在吮吸、咀嚼和牙牙学语时耦合较弱；拮抗剂肌群的相关滞后值表明，在进食行为中同步性更高，在牙牙学语时同步性更低。与15个月大婴儿的言语数据不同，9个月大婴儿在各个言语子任务中表现出一致的结果。
这些发现与先前的结果一致，即年龄较小的群体在不同行为之间的下颌协调更具变异性，而每种行为的基本组织与较大婴儿和成年人的情况密切相似。
