Aerobic Fitness and Intra-individual Variability on Neurocognitive Function in Preadolescent Children

Abstract

Increased intra-individual variability of task performance is associated with age-related cognitive decline and several diseases including schizophrenia, neurodegenerative disorders, and traumatic brain injury. Given the positive relation of aerobic fitness to cognition in children, a better understanding of the extent to which fitness relates to brain health and cognitive variability during development is of interest. PURPOSE: To determine the relation of aerobic fitness to intra-individual variability during childhood and to examine whether variability of neuroelectic parameters reflect differential cognitive control. METHODS: 93 children (39 female; range: 8-10 years) were recruited. Event-related potentials and task performance were subsequently measured during compatible and incompatible stimulus-response conditions of a modified flanker task that modulates attention and inhibition. This task modulates perceptual difficulty through congruency of target and non-target stimuli, as well as response compatibility through the manipulation of stimulus-response mappings. Intra-individual variability was characterized by computing standard deviation and ex-Gaussian parameters (mu, sigma, tau) for P3 amplitude and latency, and reaction time. RESULTS: Findings indicated that the compatible, relative to the incompatible, condition was associated with less intra-individual variability in reaction time, P3 amplitude, and P3 latency. Further, the congruent conditions, relative to the incongruent conditions, were associated with less intra-individual variability in reaction time and P3 latency. With regard to fitness, higher fitness was associated with shorter and less variable reaction time only for the incompatible condition, with no fitness-related differences observed for the P3 component. CONCLUSION: These findings suggest that tasks requiring greater cognitive control demands are associated with increased intra-individual variability. Findings also support previous research suggesting that higher amounts of fitness are associated with greater integrity of cognitive control and indicate that fitness-related differences in intra-individual variability occur after stimulus engagement and before response execution. Supported by NICHD Grant R01 HD055352