Sensorimotor factors affecting gait variability in older people--a population-based study.
BACKGROUND
Intra-individual gait variability predicts falls and disability in older people. Knowledge of factors that contribute to gait variability may lead to interventions aimed at reducing decline in mobility and falls risk. The aim of this population-based study was to examine whether poorer performance on a range of sensorimotor measures was associated with greater gait variability.


METHODS
Individuals aged 60-86 years (n = 412) were randomly selected from the Southern Tasmanian electoral roll. Spatial (step length and step width) and temporal (step time and double support time [DST]) gait measures were recorded with a GAITRite walkway. Variability for each gait measure was the standard deviation of measurements recorded during six walks. Sensorimotor measures included visual contrast sensitivity, lower limb proprioception, quadriceps strength, reaction time, and body sway (eyes open and closed). Regression analysis was used to determine the relationships between sensorimotor measures and gait variability.


RESULTS
Greater sway on a foam mat (eyes closed) was associated with greater variability in all gait measures (p < .05). Slower reaction time was associated with greater variability in both temporal gait measures (p < .05), whereas poorer proprioception was only associated with greater DST variability (p = .01) and weaker quadriceps strength with greater step time variability. Other sensorimotor factors were not independently associated with gait variability.


CONCLUSIONS
Body sway, reaction time, quadriceps strength, and proprioception are likely factors that may explain gait variability in the general older population. Further research is warranted to determine causality of these associations and whether intervention programs addressing these factors may reduce gait variability in older people.
Callisaya
Michele L
ML
Menzies Research Institute, Private Bay 23, Tasmania, Australia.
Blizzard
Leigh
L
McGinley
Jennifer L
JL
Schmidt
Michael D
MD
Srikanth
Velandai K
VK
D000368:Aged; D005684:Gait / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D011434:Proprioception / Q000502:physiology; D011930:Reaction Time; D014796:Visual Perception / Q000502:physiology