Paulo Pelicioni – Abstract

Cognitive contributions to the control of balance during stepping in young and older adults – a fNIRS study

Pelicioni PHS[1, 2], Lord SR[1, 2], Seng N[3], Halmy B[1], Sturnieks DL[1, 4] and Menant JC[1, 2]
1. Falls, Balance and Injury Research Centre, Neuroscience Research Australia, Sydney, Australia
2. School of Public Health and Community Medicine, University of New South Wales, Sydney, Australia
3. School of Medicine, University of New South Wales, Sydney, Australia
4. School of Medical Sciences, University of New South Wales, Sydney, Australia

Standing balance tasks requires cortical input, but whether this relates to balance control per se or simply the undertaking of a motor task (i.e. stepping) has not been investigated. We investigated prefrontal and motor function cortical activation during stepping tasks using fNIRS (functional near-infrared spectroscopy) in 20 young and 48 older people. The conditions comprised: supported standing using arm rests and unsupported free standing. Cortical activation in pre-frontal and motor brain areas was determined as relative changes in haemoglobin concentrations during a Stroop complex stepping task relative to that during a simpler choice-stepping reaction time (CSRT) task. We hypothesised unsupported stepping would require greater cortical activation, and this would be more so for older people. We found the older group was slower than the young group in both stepping conditions (p<0.01). Both young and old groups had slower Stroop and CSRT test times in unsupported versus supported standing (p<0.01), and in both groups this was accompanied by increased pre-frontal activation (p<0.05). The older group showed increased activation in motor areas compared with the young group in both the supported and unsupported conditions (p<0.05). No group by stepping condition effects were observed for either brain regions. These findings suggest unsupported stepping tasks take more time and involve higher pre-frontal activation regardless of age. However, the finding that motor areas are more highly activated in older people across conditions may provide insight into the slower stepping performances observed in this group.