Dubost Véronique, Kressig Reto W, Gonthier Régis, Herrmann François R, Aminian Kamiar, Najafi Bijan, Beauchet Olivier
Laboratory of Physiology, Physiopathology of Exercise and Handicap, Faculty of Medicine, University J. Monnet Saint-Etienne, France.
Hum Mov Sci. 2006 Jun;25(3):372-82. doi: 10.1016/j.humov.2006.03.004. Epub 2006 May 22.
Dual-task related gait changes have been previously reported for healthy older adults, suggesting that gait control requires attention. Compared to balance control, the involvement of attention in the control of the rhythmic stepping mechanism, as reflected by stride time variability, is not well known. In particular, under dual-task, the relative contributions of a second, attention-demanding task and changes in walking speed remain unclear. Thus, the aims of this study were (1) to assess whether walking with a slow-selected speed or walking while performing an attention-demanding task affected stride time variability in a sample of healthy older participants, and (2) to establish whether stride time variability under dual-task conditions is related either to the decrease of walking speed or the simultaneous attention-demanding task, or to both. Forty-five healthy older participants performed four experimental conditions: (1) walking at a normal self-selected speed, (2) walking at a slow self-selected speed, (3) performing a verbal fluency task when sitting on a chair, and (4) performing the verbal fluency task while walking at self-selected walking speed. Gait parameters were recorded across 15 meters, using Physilog. Results showed a significant dual-task related decrease in mean values of stride velocity, as well as a significant increase in mean values and coefficients of variation of stride time. These dual-task related changes in stride time were explained by the simultaneous performance of the verbal fluency task, the decrease of gait speed and the variability between participants. Although a relationship exists between decreased walking speed and increased stride time variability, the dual-task related increase of stride time variability was also significantly associated with the attention-demanding task, suggesting some attentional control for the rhythmic stepping mechanism of walking in healthy older adults.
先前已有研究报道健康的老年人存在与双重任务相关的步态变化，这表明步态控制需要注意力。与平衡控制相比，注意力在有节奏的步幅机制控制中的参与情况，如通过步幅时间变异性所反映的，目前尚不清楚。特别是在双重任务下，第二项需要注意力的任务以及步行速度变化的相对贡献仍不明确。因此，本研究的目的是：（1）评估以缓慢选择的速度行走或在执行需要注意力的任务时行走是否会影响健康老年参与者样本中的步幅时间变异性；（2）确定在双重任务条件下的步幅时间变异性是否与步行速度的降低、同时进行的需要注意力的任务或两者都有关。45名健康的老年参与者进行了四种实验条件：（1）以正常的自我选择速度行走；（2）以缓慢的自我选择速度行走；（3）坐在椅子上时执行语言流畅性任务；（4）以自我选择的步行速度行走时执行语言流畅性任务。使用Physilog在整个15米的距离记录步态参数。结果显示，与双重任务相关的步幅速度平均值显著下降，步幅时间的平均值和变异系数也显著增加。这些与双重任务相关的步幅时间变化可以通过语言流畅性任务的同时执行、步态速度的降低以及参与者之间的变异性来解释。虽然步行速度降低与步幅时间变异性增加之间存在关系，但与双重任务相关的步幅时间变异性增加也与需要注意力的任务显著相关，这表明健康老年人在行走的有节奏步幅机制中存在一些注意力控制。
