Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA.
Neurosci Lett. 2011 Feb 4;489(2):99-104. doi: 10.1016/j.neulet.2010.11.074. Epub 2010 Dec 7.
While cerebral lateralization has previously been well documented for many neurobehavioral functions, recent research has shown that as people age, formerly lateralized processes recruit more symmetric patterns of neural activity. Such findings provide the foundation for the model of hemispheric asymmetry reduction in older adults, or "HAROLD"[4]. Previous studies that have measured reaction time and movement time have suggested that aging does not affect manual asymmetries. However, whether these findings can be extended to kinematic variables associated with motor coordination remains largely unknown. The purpose of the current study is to determine whether asymmetries in intralimb coordination are also reduced during the aging process. We examined multidirectional reaching in two different right handed age groups, a younger group from 20 to 40 years of age, and an older group, from 60 to 80 years of age. Measures of final position accuracy, precision, and trajectory linearity showed robust asymmetries between the left and right arm groups of young adults. However, the trajectories and accuracies of the older subjects were symmetric, such that our dependent measures were not significantly different between the right and left arm groups. Our findings extend the HAROLD model to motor behavior, suggesting that aging results in decrements in motor lateralization.
尽管大脑的偏侧性在许多神经行为功能方面已有充分的记录，但最近的研究表明，随着人们年龄的增长，以前偏侧化的过程会招募更多对称的神经活动模式。这些发现为老年人半球不对称性减少模型（“HAROLD”）[4]提供了基础。先前测量反应时间和运动时间的研究表明，衰老不会影响手部的不对称性。然而，这些发现是否可以扩展到与运动协调相关的运动学变量，在很大程度上仍然未知。本研究的目的是确定在衰老过程中，肢体内协调的不对称性是否也会减少。我们在两个不同的右利手年龄组中检查了多向性伸展，一个是 20 到 40 岁的年轻组，另一个是 60 到 80 岁的老年组。最终位置准确性、精度和轨迹线性的测量结果表明，年轻成年人的左臂和右臂组之间存在明显的不对称性。然而，老年受试者的轨迹和准确性是对称的，因此我们的因变量在右臂和左臂组之间没有显著差异。我们的发现将 HAROLD 模型扩展到运动行为，表明衰老导致运动偏侧性的下降。
