Dichotic listening while walking: A dual-task paradigm examining gait asymmetries in healthy older and younger adults
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.