Yogev Galit, Plotnik Meir, Peretz Chava, Giladi Nir, Hausdorff Jeffrey M
Movement Disorders Unit, Neurology Department, Tel-Aviv Sourasky Medical Center, 6 Weizman Street, Tel-Aviv 64239, Israel.
Exp Brain Res. 2007 Mar;177(3):336-46. doi: 10.1007/s00221-006-0676-3.
While it is known that certain pathologies may impact on left-right symmetry of gait, little is known about the mechanisms that contribute to gait symmetry or how high in the hierarchy of the control of gait symmetry is regulated in humans. To assess the contribution of cognitive function to gait symmetry, we measured gait asymmetry (GA) in three subject groups, patients with Parkinson's disease (PD, n = 21), idiopathic elderly fallers (n = 15), and healthy elderly controls (n = 11). All subjects walked, under two walking conditions: usual walking and dual tasking (cognitive loading) condition. For each subject, the swing time (SW) was calculated and averaged across strides for the left and right feet (SWL and SWR). GA was defined as: 100 x /ln(SWR/SWL)/. For both the PD patients and the elderly fallers GA values were significantly higher during the usual walking condition, as compared with the control group (P < 0.01). In addition, for both the PD patients and the elderly fallers, GA significantly increased when they walked and performed a dual task, compared with the usual walking condition (P < 0.003). In contrast, dual tasking did not affect the GA of the healthy controls (P = 0.518). GA was associated with gait speed and gait variability, but no correlations were found between GA and the asymmetry of the classic PD motor symptoms. Thus, the results suggest that the ability to generate a steady, rhythmic walk with a bilaterally coordinated gait does not rely heavily on mental attention and cognitive resources in healthy older adults. In contrast, however, when gait becomes impaired and less automatic, GA apparently relies on cognitive input and attention.
虽然已知某些病理状况可能会影响步态的左右对称性，但对于导致步态对称的机制，或者人类步态对称控制在层级结构中的调控程度，我们却知之甚少。为了评估认知功能对步态对称的影响，我们测量了三组受试者的步态不对称性（GA），分别是帕金森病患者（PD，n = 21）、特发性老年跌倒者（n = 15）和健康老年对照组（n = 11）。所有受试者在两种行走条件下行走：正常行走和双重任务（认知负荷）条件。对于每个受试者，计算其摆动时间（SW），并对左右脚的步幅进行平均（SWL和SWR）。GA定义为：100×/ln(SWR/SWL)/。与对照组相比，PD患者和老年跌倒者在正常行走条件下的GA值均显著更高（P < 0.01）。此外，与正常行走条件相比，PD患者和老年跌倒者在行走并执行双重任务时，GA显著增加（P < 0.003）。相比之下，双重任务对健康对照组的GA没有影响（P = 0.518）。GA与步态速度和步态变异性相关，但未发现GA与经典PD运动症状的不对称性之间存在相关性。因此，结果表明，在健康的老年人中，以双侧协调步态产生稳定、有节奏行走的能力并不严重依赖于精神注意力和认知资源。然而，相比之下，当步态受损且自动化程度降低时，GA显然依赖于认知输入和注意力。
