The interactive effect of cognitive and physical dual task interventions on obstacle negotiation while walking in healthy young, and older, adults.

Context: Dual task performance affects obstacle crossing ability in older adults. Previous studies suggest that cognitive dual tasking can lead to changes in obstacle crossing performance in older adults, but there is a lack of evidence to support changes in obstacle crossing performance due to the influence of motor dual tasking. Aims: To investigate the interaction of cognitive and motor tasks, on obstacle crossing performance, in healthy young and older adults. Settings and Design: This is a cross sectional comparative study, conducted at Mae Fah Luang University, Thailand. Methods and Material: Sixty-four participants performed an obstacle crossing task under three conditions during a 4-meter walk test. These included walking at their normal speed with an obstacle in the middle of the walkway, followed by 2 further order-randomized walking conditions comprising a cognitive and a motor dual tasking walking condition. The spatio-temporal gait variables and obstacle crossing kinematic variables were measured using a Kinect three-camera system. Statistical Analysis Used: The means for each variable, and for each condition, were analyzed using a mixed model analysis of variance (ANOVA) with walking conditions as covariant factors. Results: A significant main interaction effect was found in gait speed (P < 0.001), step length (P = 0.046) and cadence (P = 0.011), but there was only a significant between-group difference in step length during obstacle crossing, while performing a cognitive dual task (P = 0.008) and a motor dual task (P < 0.001). Conclusions: Older adults adopted a conservative strategy, and walked with a shorter step length, when stepping over an obstacle while performing a dual task.