Age-dependent differences in the time course of postural control during sensory perturbations.
OBJECTIVE
With research demonstrating that older adults are more likely to sustain a loss of balance than younger adults, the need for an account of age-related differences in postural control is apparent. Several measures of balance reported in the literature have assessed balance using an average or summative measure over the course of a trial, typically lasting several seconds. One limitation related to these measures is the inability to assess the time-course of postural control occurring throughout the trial. To this end, the current investigation assessed the temporal changes in balance both as a function of age and sensory environment.


METHODS
Postural control was assessed from 10 older adults (69.3+/-4.7 years) and 10 younger adults (22.1+/-1.7 years) over the course of fifteen seconds in three different sensory environments. The sensory manipulations involved sway-referenced rotation of the floor and/or the visual surround.


RESULTS
Significant differences (p=0.001) in overall postural stability were observed between the two groups on all three sensory conditions. Additionally, time-course changes were observed between the two groups when the environment did not cause sensory conflict (sway-referenced floor or room only). However, when the environment created a situation of sensory conflict (sway-referenced floor and room) both groups followed the same time-course of postural changes.


CONCLUSIONS
Interestingly, the time course of postural control for the older adults on the easiest condition was mimicked by the younger adults on a more challenging condition. However, when faced with sensory conflict there were no group differences in the time course of postural control. The findings suggest an age-related decline in the temporal control of posture in altered sensory environments.
Dickin
D Clark
DC
Dept. of Health, Exercise and Sport Sciences, Texas Tech University, Lubbock, 79409, USA. clark.dickin@ttu.edu
Brown
Lesley A
LA
Doan
Jon B
JB
D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000375:Aging; D004780:Environment, Controlled; D005246:Feedback; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013997:Time Factors