Choice stepping reaction time: A composite measure of falls risk in older people

Background. This study investigated the neuropsychological, sensorimotor, s peed, and balance contributions to a new test of choice stepping reaction t ime (CSRT) and determined whether this new test is an important predictor o f falls in older people. Methods. A total of 477 retirement-village residents aged 62 to 95 years (m ean +/- SD, 79.2 +/- 6.2 years) took the CSRT test, which required them to step onto one of four panels that were illuminated in a random order. The s ubjects also took tests that measured neuropsychological, sensorimotor, spe ed, and balance function. Results. Multiple regression analysis revealed that poor performance, in Pa rt B of the Trail Making Test (a neuropsychological test) and impaired quad riceps strength, simple reaction time, sway with eyes open on a compliant s urface, and maximal balance range were the best predictors of increased CSR Ts (multiple r(2) = .45). Subjects with a history of falls had significantl y increased CSRTs compared with nonfallers (1322 +/- 331 milliseconds and 1 168 +/- 203 milliseconds, respectively). Impaired CSRT was a significant an d independent predictor of falls, as were two complementary sensory measure s (visual contrast sensitivity and lower limb proprioception). Of these mea sures, CSRT was the most important in predicting falls. Furthermore, the in clusion of CSRT in the model excluded measures of strength, central process ing speed, and balance, because these could not provide nonredundant inform ation for the prediction of falls. Conclusions. This study identifies a new test that provides a composite mea sure of falls risk in older people and elucidates the relative importance o f specific physiological and neuropsychological systems in the initiation o f fast and appropriate step responses.