Department of Human Physiology and Institute of Neuroscience, University of Oregon, Eugene, OR, USA.
J Neurophysiol. 2012 Oct;108(8):2215-29. doi: 10.1152/jn.01193.2011. Epub 2012 Jul 25.
The question of how infants attain upright sitting is at the core of understanding the development of most functional abilities. Our simple, practical method of securing the hips and different trunk segments while evaluating the infant's ability to vertically align and stabilize the trunk in space contributes a useful method and new insights into the development of upright control. Previous studies have considered the trunk to develop as a single segment. The goal of the present study was to examine how postural control changes across multiple trunk segments during typical development (TD) of sitting balance. For this purpose, electromyography (EMG) and kinematic data were collected at four levels of trunk support (axillae, midribs, waist, hips), in a longitudinal study of eight TD infants (3-9 mo of age). We found that developmental changes in stability were specific to the region of the trunk being investigated, changes in antagonistic muscle activity differed for the anterior-posterior versus the medial-lateral axis, and the relationship between muscle activation and movement changed from erratic attempts to gain upright position to anticipatory graded responses as infants developed upright control through a four-stage behavioral process. This information can be used by researchers to further refine hypotheses regarding this developmental process and by clinicians who wish to develop and test more specific treatment programs for children with postural dysfunction.
婴儿如何获得直立坐姿的问题是理解大多数功能能力发展的核心。我们通过固定婴儿的臀部和不同的躯干节段，同时评估婴儿在垂直方向上对齐和稳定躯干的能力，从而提供了一种有用的方法和新的见解，以了解直立控制的发展。先前的研究认为躯干作为一个单一的节段发展。本研究的目的是检验在坐姿平衡的典型发育过程中（TD），多个躯干节段的姿势控制如何发生变化。为此，在对 8 名 TD 婴儿（3-9 个月龄）的纵向研究中，我们在四个躯干支撑水平（腋窝、中肋、腰部、臀部）上收集了肌电图（EMG）和运动学数据。我们发现，稳定性的发育变化是特定于所研究的躯干区域的，拮抗肌活动的变化在前-后和内-外侧轴上是不同的，肌肉激活和运动之间的关系从不稳定的尝试获得直立位置到随着婴儿通过四个阶段的行为过程发展直立控制而转变为预期的分级反应。这些信息可以供研究人员进一步完善关于这一发育过程的假设，并为希望开发和测试针对姿势功能障碍儿童的更具体治疗方案的临床医生提供信息。
