Rochester L, Galna B, Lord S, Burn D
Institute for Ageing and Health, Newcastle University, Clinical Ageing Research Unit, Campus for Ageing and Vitality, United Kingdom.
Institute for Ageing and Health, Newcastle University, Clinical Ageing Research Unit, Campus for Ageing and Vitality, United Kingdom.
Neuroscience. 2014 Apr 18;265:83-94. doi: 10.1016/j.neuroscience.2014.01.041. Epub 2014 Feb 4.
Dual-task interference during gait is a common phenomenon in older adults and people with Parkinson's disease (PD). Dual-task performance is driven by cognitive processes involving executive function, attention and working memory which underpin resource capacity and allocation. The underlying processes that contribute to dual-task interference are poorly understood, and confounded by methodological differences. The aim of this study was to explore the nature of dual-task interference in PD with respect to age-matched controls. We examined 121 people with early PD and 189 controls and controlled for baseline task demand on both tasks allowing between-group differences to be attributed to dual-task interference rather than differences in baseline performance. We also compared a wide range of gait characteristics to evaluate the pattern of interference. Participants walked for two minutes at a preferred pace under single- and dual-task (test of working memory capacity-digit span recall) conditions. In a subgroup task demand was increased (digit span+1) (n=55 control, n=44 PD) to assess the influence of resource capacity. Finally the association between dual-task interference with motor and cognitive characteristics was examined to evaluate resource capacity and allocation. PD and controls responded similarly to the dual-task for all gait characteristics except for step width and step width variability and this was the same when task demand increased (dual+1). Control participants took wider steps (p=0.006) and step width variability increased significantly for controls (p=0.001) but not PD. Interference was specific to the gait characteristic rather than a global pattern of impairment. Digit span error rates were not significantly different between groups during dual-task performance. There were no significant correlations with dual-task interference and global cognition, motor deficit, and executive function for either group. Effects of dual-tasks on gait performance are twofold and specific to the gait characteristic. They reflect an age-related reduction in gait performance (especially forward progression) in PD and controls possibly due to reduced resource capacity; and secondly, show postural stability during walking in early PD is disproportionately affected highlighting a PD-specific dual-task co-ordination deficit. Further work is required to identify the cognitive, executive and motor correlates of dual-task interference from which inferences about underlying cognitive processes can be made. These findings inform an understanding of dual-task impairment in early PD and suggest that management should target postural control under dual-task conditions from the early stages.
步态中的双重任务干扰在老年人和帕金森病（PD）患者中是一种常见现象。双重任务表现由涉及执行功能、注意力和工作记忆的认知过程驱动，这些认知过程支撑着资源容量和分配。导致双重任务干扰的潜在过程尚不清楚，且因方法学差异而混淆。本研究的目的是探讨PD患者与年龄匹配的对照组相比双重任务干扰的本质。我们检查了121例早期PD患者和189名对照组，并控制了两项任务的基线任务需求，使组间差异可归因于双重任务干扰而非基线表现的差异。我们还比较了多种步态特征以评估干扰模式。参与者在单任务和双重任务（工作记忆容量测试 - 数字广度回忆）条件下以偏好速度行走两分钟。在一个亚组中，任务需求增加（数字广度 +1）（n = 55名对照组，n = 44名PD患者）以评估资源容量的影响。最后，研究双重任务干扰与运动和认知特征之间的关联以评估资源容量和分配。除步宽和步宽变异性外，PD患者和对照组在所有步态特征上对双重任务的反应相似，当任务需求增加（双重任务 +1）时情况也是如此。对照组参与者步幅更宽（p = 0.006），对照组的步宽变异性显著增加（p = 0.001），但PD患者没有。干扰是特定于步态特征而非整体损伤模式。在双重任务表现期间，两组之间的数字广度错误率没有显著差异。两组中双重任务干扰与整体认知、运动缺陷和执行功能均无显著相关性。双重任务对步态表现的影响是双重的且特定于步态特征。它们反映了PD患者和对照组中与年龄相关的步态表现下降（尤其是向前推进），这可能是由于资源容量减少；其次，表明早期PD患者行走时的姿势稳定性受到不成比例的影响，突出了PD特有的双重任务协调缺陷。需要进一步的工作来确定双重任务干扰的认知、执行和运动相关性，从中可以推断出潜在的认知过程。这些发现有助于理解早期PD中的双重任务损伤，并表明管理应从早期阶段就针对双重任务条件下的姿势控制。
