Recent evidence suggests increased activity of the pre-frontal cortex (PFC) is associated with sensorimotor disturbances of standing balance. Here we manipulate sensorimotor inputs and concurrently load cognitive resources in order to investigate the functional role of PFC activity during standing balance, and how this changes with healthy ageing. Healthy younger (n= 24; mean age= 20.8 years) and older (n= 25; mean age = 70.6 years) adults maintained balance while sensorimotor inputs were manipulated by removing vision, reducing the base of support, and reducing proprioceptive feedback. To load cognitive resources, each balance condition was undertaken alone or simultaneously with a cognitive task (dual-task). Functional near infrared spectroscopy (fNIRS) measured PFC activity and a force-plate measured postural sway. When comparing dualtasks relative to single balance tasks (dual-task effect), at lower levels of balance task demand, the older adults exhibited increased PFC activity and similar levels of postural sway. However, at higher levels of balance task demand, a limit to PFC activity was observed and postural sway became more unstable in older adults. In contrast, for younger adults at higher levels of balance task demand, the dual-task effect resulted in an increase in PFC activity and postural sway was not unduly affected. These results suggest that PFC activity is compensating for sensorimotor deficits to maintain stability, and that a cognitive resource limit is reached for easier balance tasks in older people compared to younger people. These results suggest that increasing cortical capacity in older people may improve their balance.

Item Type:	Refereed Article
Keywords:	ageing, balance, cognitive demands, compensation hypothesis, fNIRS, sensorimotor control
Research Division:	Psychology
Research Group:	Cognitive and computational psychology
Research Field:	Sensory processes, perception and performance
Objective Division:	Health
Objective Group:	Specific population health (excl. Indigenous health)
Objective Field:	Health related to ageing
UTAS Author:	St George, RJ (Dr Rebecca St George)
UTAS Author:	Hinder, MR (Associate Professor Mark Hinder)
UTAS Author:	Puri, R (Mr Rohan Puri)
UTAS Author:	Walker, E (Miss Eliza Walker)
UTAS Author:	Callisaya, ML (Dr Michele Callisaya)
ID Code:	142437
Year Published:	2021 (online first 2020)
Funding Support:	National Health and Medical Research Council (1036234)
Web of Science® Times Cited:	15
Deposited By:	Psychology
Deposited On:	2021-01-18
Last Modified:	2021-04-08
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