Elble R J, Cousins R, Leffler K, Hughes L
Department of Neurology, Southern Illinois University School of Medicine, Springfield 62794-1413, USA.
Brain. 1996 Oct;119 ( Pt 5):1705-16. doi: 10.1093/brain/119.5.1705.
Patients with multiple deep cerebral infarcts and white matter degeneration commonly exhibit a hesitant, shuffling gait, with preserved arm swing. This pattern of walking is called lower-half or lower-body parkinsonism. Gait initiation and turning consist of one or more short, hesitant steps in which the feet shuffle across the floor. This abnormality of gait initiation was studied with quantitative motion analysis in five patients, ages 74-87 years. Five men and five women with normal mobility and comparable ages exhibited three key events of gait initiation: (i) activation of tibialis anterior and inactivation of triceps surae produced bilateral ankle dorsiflexion and a sagittal moment of force that propelled the body anteriorly; (ii) abduction of the swing hip occurred simultaneously with event (i); and (iii) abrupt 3-10 degrees flexion of the support hip and knee occurred nearly simultaneously with events (i) and (ii) and produced a transient reduction in vertical force beneath the support foot. Events (ii) and (iii) produced a coronal moment of force about the ankles that propelled the body toward the support foot. Thus, in normal gait initiation, a smooth sequence of postural shifts propels the body anterolaterally toward the support limb, culminating in a forward step. The patients, by comparison, exhibited errant deviations in their postural shifts of gait initiation, and one or more aborted steps frequently preceded the first complete step. Nevertheless, all patients employed the usual three key events in their initial attempt at stepping, consistent with a normal motor strategy of gait initiation. These results and previous clinical observations suggest that the principal locomotor deficit is an impaired generation of postural shifts that mediate changes from one steady-state posture or movement to another.
患有多发性深部脑梗死和白质变性的患者通常表现出步态迟疑、拖曳，而摆臂功能保留。这种行走模式被称为下半部或下半身帕金森综合征。步态起始和转身由一个或多个短暂、迟疑的步骤组成，在此过程中脚在地面上拖行。通过定量运动分析对5名年龄在74至87岁的患者的这种步态起始异常进行了研究。5名行动能力正常且年龄相仿的男性和5名女性在步态起始时表现出三个关键事件：(i) 胫前肌激活和小腿三头肌失活产生双侧踝关节背屈以及推动身体向前的矢状向力矩；(ii) 摆动侧髋关节外展与事件(i) 同时发生；(iii) 支撑侧髋关节和膝关节突然屈曲3至10度，几乎与事件(i) 和(ii) 同时发生，并导致支撑脚下垂直力短暂降低。事件(ii) 和(iii) 产生了围绕踝关节的冠状向力矩，将身体推向支撑脚。因此，在正常的步态起始中，一系列平稳的姿势转换将身体向前外侧推向支撑肢体，最终迈出向前的一步。相比之下，这些患者在步态起始的姿势转换中表现出错误的偏差，并且在第一个完整步骤之前经常会出现一个或多个未成功的步骤。然而，所有患者在最初尝试迈步时都采用了通常的三个关键事件，这与正常的步态起始运动策略一致。这些结果和先前的临床观察表明，主要的运动缺陷是介导从一种稳态姿势或运动到另一种稳态姿势或运动变化的姿势转换产生受损。
