Do voluntary step reactions in dual task conditions have an added value over single task for fall prediction? A prospective study.

BACKGROUND AND AIMS: Stepping reactions play a critical role in responding to balance perturbations, whether they are a consequence of external perturbation or self-induced in nature. The aim of the present study was to determine prospectively the capacity of voluntary stepping performance in singleand dual-task conditions, to predict future falls among older community-dwelling persons. We also aimed to assess whether dual task conditions have an added value over single tasks for fall prediction.

METHODS: A total of 100 healthy old volunteers (mean age 78.4±5.7 yrs), from two self-care protected retirement homes for older adults, performed the Voluntary Step Execution Test in single- and dual-task conditions as a reaction time task while standing on a single force platform. Step initiation, preparatory and swing phases, and foot-contact time were extracted from data on center of pressure and ground reaction force. One-year fall incidences were monitored.

RESULTS: Ninety-eight subjects completed the one-year follow-up, 49 non-fallers, 32 one-time fallers, and 17 recurrent fallers (two or more falls). Recurrent fallers had significantly slower voluntary step execution times in both single- and dual-task conditions, especially due to a slower preparation phase. Two stepwise (backward) logistic regression models showed that longer step execution times have strong predictive value for falls in both single- and dual-task conditions (odds ratio (OR) 8.7 and 5.4, respectively, p<0.05).

CONCLUSIONS: Voluntary Step Execution Test in both single- and dual-task conditions is a simple and safe examination which can potentially and effectively predict future falls, with no added value to dual- over single-task condition.