Date of Award

2017

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Doctor of Philosophy

School

School of Arts and Humanities

First Supervisor

Professor Julie Ann Pooley

Second Supervisor

Professor Craig Speelman

Abstract

This research project sought to investigate the relationship between physical exercise and cognition in children with and without a neurodevelopmental condition. To achieve this aim, three approaches were undertaken to explore the exercise and cognition relationship. The first approach sought to understand the efficacy of exercise interventions on cognition in individuals with a neurodevelopmental disorder. The second approach was to understand the effectiveness of an exercise activity when compared to a cognitively-engaging tablet game activity on measures of implicit learning and attention in children with and without a neurodevelopmental condition. The third approach was to investigate if psychophysiological measures could account for the cognitive effect observed after exercising in children with and without a neurodevelopmental condition. Taking the approaches together, this research project focused on investigating the efficacy, effect, and mechanism of the exercise-cognition relationship.

To investigate the efficacy of the exercise interventions, a meta-analytic review was conducted on 22 studies from the neurodevelopmental literature. The main findings from this meta-analysis revealed an overall small-to-medium effect size of exercise on cognition, supporting the efficacy of applying exercise interventions to young individuals with a neurodevelopmental disorder. Similar to the general population, physical exercise has been demonstrated to improve some but not all cognitive functions, with some individuals demonstrating no change in cognitive function after exercising.

In terms of the effects of physical exercise, this project conducted an experimental study comparing a moderate-intensity exercise activity with a tablet game activity for a period of 12 minutes in 35 children aged 6-11 years. Overall, the study found that the effect of exercise was comparable to the tablet activity across the reaction time measures, but not on the accuracy performance of the implicit learning and attention tasks. Overall, exercise activity led to a better accuracy performance on implicit learning and executive attention compared to the tablet activity, particularly in children with a neurodevelopmental condition.

The last part of this project was an extension of the experimental study whereby psychophysiological measures were investigated based on a proposed detrended fluctuation analysis (DFA). This investigation found that galvanic skin response (GSR), as indexed by its scaling exponent, was related to whether children revealed a change in cognitive function after receiving the exercise activity, particularly on executive attention. Importantly, this relationship was also able to account for children who did not demonstrate a cognitive effect of exercise. This result was not evident in the electroencephalogram (EEG) measures. This investigation concluded that the effect of exercise on executive attention was dependent on the interplay between an individual’s arousal system, cognitive task demand, and the novelty of the exercise activity.

Taking the findings together, this project highlights the importance of individual differences to the exercise and cognition relationship. Specifically, this project demonstrated the feasibility of investigating the scaling exponent, via fractal analysis (e.g., DFA), as an index of individual differences. Additionally, fractal analysis is a valuable tool to assist in further understanding the mechanism underlying the exercise-cognition relationship, particularly on the influence of individual differences

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