São Paulo State University (UNESP), Human Movement Research Laboratory (MOVI-LAB), Graduate Program in Movement Science, Department of Physical Education, Bauru, SP, Brazil.
São Paulo State University (UNESP), Laboratory of Information, Vision and Action (LIVIA), Graduate Program in Movement Science, Department of Physical Education, Bauru, SP, Brazil.
Gait Posture. 2019 Sep;73:291-298. doi: 10.1016/j.gaitpost.2019.07.375. Epub 2019 Jul 31.
People with Parkinson's disease (PD) do not differ from neurologically healthy individuals in obstacle circumvention during walking, therefore they are able to use visual feedback adequately to control motor behavior in this task. However, individuals are often distracted by the secondary task when circumventing an obstacle. An increased cognitive load can require prolonged gaze fixation time on a location of interest to compensate for longer information processing duration.
To investigate the effects of cognitive dual tasking (DT) on gaze behavior during waking with obstacle circumvention in people with PD and control group, and to determine the impact of gaze behavior on motor strategy.
Fifteen individuals with PD (PD-group) and 15 neurologically healthy individuals walked at a self-selected speed over a walkway and circumvented an obstacle centered in the walkway. The experimental conditions (5 trials each one) included obstacle circumvention without DT (OC) and obstacle circumvention with DT (OCDT). In the cognitive task, the participant mentally counted the number of times a target number appeared in an audio recording. We analyzed gaze behavior (i.e. number of gaze fixations and duration on the ground and obstacle), standard gait measures and DT cost. Two-way ANOVAs were completed for gait parameters and moment of fixation.
There was no significant difference in DT cost between groups and no obstacle contacts. The participants performed a longer mean duration of fixations on the ground during OCDT compared to OC. Group x condition interactions indicated that the PD-group delayed the obstacle fixation relative to the NHI for OCDT (p < 0.001) and presented greater medial-lateral body clearance (p < 0.001) and longer double support time (p < 0.001) during OCDT compared to OC.
The results of this study suggest that deficits in locomotion during DT in PD-group may be caused, at least in part, by a reduced ability to fixate gaze at appropriate times during walking.
帕金森病 (PD) 患者在行走时与神经健康个体在避开障碍物方面没有区别，因此他们能够在该任务中充分利用视觉反馈来控制运动行为。然而，当避开障碍物时，个体通常会被次要任务分心。认知负荷增加可能需要延长对感兴趣位置的注视时间，以补偿更长的信息处理时间。
研究认知双重任务 (DT) 对 PD 患者和对照组在清醒状态下绕过障碍物时的注视行为的影响，并确定注视行为对运动策略的影响。
15 名 PD 患者 (PD 组) 和 15 名神经健康个体以自选择速度在步道上行走并绕过步道中心的障碍物。实验条件 (每种条件 5 次试验) 包括无 DT 的障碍物回避 (OC) 和有 DT 的障碍物回避 (OCDT)。在认知任务中，参与者在听觉记录中数目标数出现的次数。我们分析了注视行为（即注视地面和障碍物的次数和持续时间）、标准步态测量和 DT 成本。完成了用于步态参数和注视时间的双向方差分析。
组间无 DT 成本差异，也无障碍物接触。与 OC 相比，参与者在 OCDT 期间地面注视的平均持续时间更长。组 x 条件的交互作用表明，与 NHI 相比，PD 组在 OCDT 中延迟了对障碍物的注视 (p<0.001)，并且在 OCDT 中呈现出更大的内侧-外侧身体间隙 (p<0.001) 和更长的双支撑时间 (p<0.001)。
本研究结果表明，PD 组在 DT 期间运动障碍的原因至少部分是由于在行走过程中注视时间减少而导致的。
