ABSTRACT

Dual-task studies have employed various cognitive tasks to evaluate the relationship between gait and cognition. Most of these tests are not specific to a single cognitive ability or sensory modality and have limited ecological validity. In this study, we employed a dual-task paradigm using Dichotic Listening (DL) as concomitant cognitive task to walking. We argue that DL is a robust task to unravel the gait-cognition link in different healthy populations of different age groups. Thirty-six healthy older adults (Mean = 67.11) and forty younger adults (Mean = 22.75) participated in the study. DL consists of three conditions where spontaneous attention and attention directed to right or left-ear are tested while walking. We calculated dual-task costs (DTCs) and percent of baseline values for three spatio-temporal gait parameters as compared to single-walking during three DL conditions. Results showed that both groups had larger DTCs on gait during volitional control of attention, i.e., directing attention to one specific ear. Group differences were present across all DL conditions where older adults reported consistently less correct stimuli than younger participants. Similar findings were observed in the neuropsychological battery where older participants showed restricted abilities for executive functioning and processing speed. However, the main finding of this investigation was that younger adults exhibited unique adjustments in step length variability as shown by changes in DTCs and percent of baseline values. Particularly, an asymmetric effect was observed on the young group when attending right-ear stimuli. We interpreted this gait asymmetry as a compensatory outcome in the younger participants due to their optimal perceptual and motor abilities, which allow them to cope suitably with the dual-task situation. Many studies suggest that gait asymmetries are indicators of pathology, the present data demonstrate that gait asymmetries arise under specific constraints in healthy people as an adaptation to task requirements.

摘要

双任务研究采用了各种认知任务来评估步态与认知之间的关系。这些测试大多数都不是针对单一的认知能力或感觉方式，并且生态有效性有限。在这项研究中，我们采用了双任务范式，使用双耳听力（DL）作为行走的伴随认知任务。我们认为，在不同年龄组的不同健康人群中，DL是解开步态与认知联系的一项艰巨任务。三十六名健康的老年人（平均值=  67.11）和四十岁的年轻人（平均值 = 22.75）参加了这项研究。DL由三个条件组成，在这些条件下，步行时会测试自发注意力和对右耳或左耳的注意力。我们计算了三种时空步态参数的双重任务成本（DTC）和基线值的百分比，与三种DL条件下的单步行走相比。结果表明，在自愿控制注意力（即将注意力转移到一只特定的耳朵）期间，两组步态的DTC都较大。在所有DL条件下，老年人报告的正确刺激力始终比年轻参与者差，存在群体差异。在神经心理学领域也观察到了类似的发现，老年参与者表现出执行功能和处理速度的能力受到限制。然而，这项研究的主要发现是，较年轻的成年人表现出步长变异性的独特调整，如DTC的变化和基线值的百分比所示。特别是，在参加右耳刺激时，对年轻组观察到不对称效应。由于他们的最佳知觉和运动能力，我们将这种步态不对称性解释为年轻参与者的一种补偿性结果，这使他们能够适当地应对双重任务情况。许多研究表明，步态不对称性是病理的指标，目前的数据表明，步态不对称性是在健康人的特定约束下适应任务要求而出现的。参加右耳刺激时，对年轻组观察到不对称效应。由于他们的最佳知觉和运动能力，我们将这种步态不对称性解释为年轻参与者的一种补偿性结果，这使他们能够适当地应对双重任务情况。许多研究表明，步态不对称性是病理的指标，目前的数据表明，步态不对称性是在健康人的特定约束下适应任务要求而出现的。参加右耳刺激时，对年轻组观察到不对称效应。由于他们的最佳知觉和运动能力，我们将这种步态不对称性解释为年轻参与者的一种补偿性结果，这使他们能够适当地应对双重任务情况。许多研究表明，步态不对称是病理的指标，目前的数据表明，步态不对称是在健康人的特定约束下适应任务要求而出现的。