Article

Functional and structural imaging studies have demonstrated the involvement of
the brain in balance control. Nevertheless, how decisive grey matter density and
white matter microstructural organisation are in predicting balance stability,
and especially when linked to the effects of ageing, remains unclear. Standing
balance was tested on a platform moving at different frequencies and amplitudes
in 30 young and 30 older adults, with eyes open and with eyes closed. Centre of
pressure variance was used as an indicator of balance instability. The mean
density of grey matter and mean white matter microstructural organisation were
measured using voxel-based morphometry and diffusion tensor imaging,
respectively. Mixed-effects models were built to analyse the extent to which age,
grey matter density, and white matter microstructural organisation predicted
balance instability. Results showed that both grey matter density and age
independently predicted balance instability. These predictions were reinforced
when the level of difficulty of the conditions increased. Furthermore, grey
matter predicted balance instability beyond age and at least as consistently as
age across conditions. In other words, for balance stability, the level of
whole-brain grey matter density is at least as decisive as being young or old.
Finally, brain grey matter appeared to be protective against falls in older
adults as age increased the probability of losing balance in older adults with
low, but not moderate or high grey matter density. No such results were observed
for white matter microstructural organisation, thereby reinforcing the
specificity of our grey matter findings.
CI - Copyright (c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS