Risk of falling: predictors based on reduced strength in persons previously affected by polio.
OBJECTIVE
To examine the contributions of sensorimotor factors to postural control and falling in people with prior polio and to determine whether these contributions differ from those found in normal populations.


METHODS
Survey and case-control study.


METHODS
A falls and balance laboratory in Australia.


METHODS
Forty persons with prior polio (age range, 28-71 y) and 38 age- and sex-matched control subjects.


METHODS
Not applicable.


METHODS
Lower-limb muscle strength, sway, vision, lower-limb sensation, reaction time, foot-tapping speed, and falls.


RESULTS
Compared with the control subjects, the prior polio subjects performed similarly in sensory tests but worse in tests that involved a motor component. Within the prior polio group, lower-limb strength was strongly associated with postural sway on a compliant surface and explained more of the variance in sway than in control subjects. Prior polio subjects who fell multiple times had reduced lower-limb strength, slower reaction time, lower foot-tapping speed, and increased sway compared with those who fell less often. However, the rate of decline in lower-limb strength within the prior polio group did not exceed normal, age-related changes.


CONCLUSIONS
This investigation of prior polio subjects provides an appropriate model for studying muscle weakness as a falls risk factor. Weakness was directly associated with falls, and had an indirect effect mediated through increased sway.
Lord
Stephen R
SR
Prince of Wales Medical Research Institute, Randwick, Sydney, NSW, Australia. s.lord@unsw.edu.au
Allen
Gabrielle M
GM
Williams
Philippa
P
Gandevia
Simon C
SC
D000058:Accidental Falls / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D001315:Australia; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016262:Postpoliomyelitis Syndrome / Q000503:physiopathology* / Q000534:rehabilitation; D011187:Posture; D011597:Psychomotor Performance; D011930:Reaction Time; D012044:Regression Analysis; D012306:Risk