< Back to previous page

Project

Effects of Intellectual Disability and Sport Expertise on Cognitive-Motor Dual-Task Performance

Athletes with intellectual disability (ID) comprise a specific population that allows for the unique examination of the opposing effects of cognitive deficits and sport expertise on postural control and motor-cognitive dual-task performance. On the one hand, there is evidence that individuals with ID have impaired postural control and dual-tasking ability, indicating ID’s negative effect. On the other hand, training related to the acquisition of athletic competence is associated with beneficial effects on postural control and dual-task performance. However, the extent to which the positive effects of training can overcome the negative effects of ID remains unclear. The collection of four studies comprising this doctoral research, therefore, examined the interactive effects of ID and sport expertise on postural control and dual-task performance.

The first study examined the combined effects of ID and sport expertise on postural control. We assessed center-of-pressure (COP) based measures of postural control of four groups of participants (i.e., 14 athletes with ID, 14 athletes without ID, 15 non-athletes with ID, and 15 non-athletes without ID) in static and dynamic postural conditions. We found that sport expertise did not have any significant effect on postural control, while ID exerted a large negative effect on postural control, particularly in dynamic postural conditions. The postural control of participants with ID was characterized by high COP velocity and unvarying COP entropy across different postural conditions, which are associated with increased postural stiffness and reliance on a cognitively supervised postural control for postural threats, respectively.

In the second study, we implemented a scoping review of the dual-task literature to summarize the testing procedures and patterns of dual-task interference in individuals with ID. From the 22 studies that met our inclusion criteria, the dual-task testing procedures and reporting were not consistent between studies, which restricted any clear conclusion being made about the nature of dual-task ability and specific dual-task deficits in individuals with ID. Heterogeneity between studies were notable in inclusion of procedures to ensure comparable single-task performance between individuals with ID and chronological age-matched controls, measurement and reporting of dual-task performance for each single-task, and specifying instructions related to task priority. Moreover, thematic content of studies included in the review highlighted gaps in dual-task literature on individuals with ID, notably on the trainability of dual-task ability in this population.

For the last two studies, we conducted posture-cognition dual-task experiments; one tested athletes with and without ID and the other examined non-athletes with and without ID. The third study investigated dual-task performance and adaptive responses to dual-task demands in 29 elite athletes with ID and 29 age-, sex, and training volume-matched athletes without ID. Participants performed a postural (i.e., balancing on top of a rocking board) and a memory (i.e., visual recognition task) task separately and concurrently. We assessed memory accuracy and COP excursion, as well as automaticity of postural control (COP entropy). For the postural task, athletes with and without ID exhibited comparable COP excursion in both single- and dual-task conditions. Adapting to a dual-task situation, athletes without ID automatized their postural control and maintained single-task level of COP excursion. In contrast, athletes with ID prioritized balance to reduce COP excursion but this strategy came at the expense of memory accuracy. While athletes without ID’s memory accuracy was unaffected by dual-tasking, athletes with ID sustained significant cognitive dual-task costs.

For the final study, besides determining whether the same pattern of dual-task findings observed in athletes will be replicated in non-athletes, we examined the explanatory scope of the general resource and task coordination accounts of dual-task cost for the effects of ID on dual-task performance. We had 36 participants—12 with ID and 24 without ID—perform postural (in static and dynamic conditions) and memory tasks separately and concurrently. Improving on the third study’s design, we adjusted the difficult of the memory task according to individual differences in cognitive abilities. Core cognitive control processes (i.e., inhibition, task switching, and working memory updating) and intellectual functions were also assessed. We observed non-athletes without ID outperforming non-athletes with ID in cognitive and postural task under dual-task conditions, but significant cognitive dual-task costs was observed only in individuals with ID while in the dynamic platform condition. The two accounts of dual-task costs together could not completely capture the sources of ID-related effects on dual-task performance and, of these two accounts, only general resource accounts provided significant explanatory value to dual-task performance.

Findings of the four studies comprising this doctoral research clearly indicate that the effect of ID on postural control and dual-task performance is large, evident from the significantly larger COP excursions and dual-task costs in individuals with ID relative to individuals without ID. In contrast, the effect of sport expertise is small. Sport expertise may provide benefits to postural control that would allow individuals with ID to perform as well as individuals without ID in specific postural conditions. However, more difficult postural challenges and dual-tasking situations bring out the detrimental effects of ID that sport expertise is not able to overcome completely. The level of expertise achieved by athletes with ID from training, at present, is not sufficient to overcome the disadvantage in performance posed by ID.

Date:1 Apr 2017 →  31 Mar 2023
Keywords:Balance, Sport
Disciplines:Orthopaedics, Human movement and sports sciences, Rehabilitation sciences
Project type:PhD project