Revisiting the Relationship Between Internal Focus and Balance Control in Young and Older Adults.

Victoria W K Chow,Toby J Ellmers,Thomson W L Wong,Toby C T Mak,William R Young

doi:10.3389/fneur.2018.01131

Victoria W K Chow, Toby J Ellmers + Show 3 more

Open Access

https://doi.org/10.3389/fneur.2018.01131

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Abstract

Research highlights the detrimental effect that directing too much conscious attention toward movement can have on postural control. While this concept has received support from many studies, recent evidence demonstrates that this principle does not always translate to aging clinical populations. Given the increasing clinical interest in this topic, the current study evaluated if the original notion (that an internal focus results in compromised balance performance) is upheld in young and older adults during a challenging balance task where we are able to objectively corroborate changes in attentional focus; using an electroencephalography (EEG) method previously identified as an objective indicator of conscious movement control. This method assesses the neural coherence, or “communication,” between T3 (verbal-analytical) and Fz (motor-planning) regions of the brain. Thirty-nine young and 40 older adults performed a challenging balance task while holding a 2-meter pole under two randomized conditions: Baseline and Internal focus of attention (directing attention internally toward movement production). Results showed that young adults demonstrated increased EEG T3-Fz coherence in conjunction with increased sway path during the Internal focus condition. However, no significant differences were observed in older adults between conditions for any measure. The current study provides supporting evidence for the detrimental effect that adopting an Internal focus can have on postural control—especially in populations able to govern these processes in a relatively “automatic” manner (e.g., young adults). However, this work illustrates that such observations may not readily translate between populations and are not robust to age-related changes. Further work is necessary to examine mechanisms underlying this clear translational issue.

Highlights

Traditional conceptualizations have viewed postural control as a largely automatic process requiring minimal conscious involvement
Re-visiting Attentional Focus and Postural Control control is often reported in young adults [e.g., [3, 4]], these decrements appear to be pronounced in older adults [1]
In light of previous validations of the EEG protocol [20, 21, 25] and the clear changes observed in EEG T3-Fz coherence between conditions in young adults indicating a greater reliance on cognitive verbal-analytical processes to regulate motor output, we suggest that the lack of any statistical association between metrics indicating percentage change cannot be primarily due to poor sensitivity in the EEG T3-Fz measurement

Summary

Introduction

Traditional conceptualizations have viewed postural control as a largely automatic process requiring minimal conscious involvement. Seminal work published by Wulf and colleagues describes enhanced postural stability when performers direct attention externally (e.g., toward ensuring markers placed on a stabilometer remain horizontal), rather than internally (e.g., toward minimizing movement in the ankles) [5, 6] These findings have since been replicated during other experimental conditions designed to limit the amount of conscious attention directed toward postural control in both young and older adults [7,8,9]. This has led researchers to suggest that stability may be enhanced during balance tasks by promoting the use of more automatic control mechanisms [6, 7, 9]. It has been suggested that adopting an internal focus of attention may disrupt the “automatic” processes typically used to regulate posture, leading to superfluous muscle activity and constrained motor outputs [10]

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