SAFE EVALUATION METHOD FOR FALL RISK: A SITTING TASK CAN PREDICT A REDUCTION IN GAIT SPEED UNDER THE DUAL-TASK CONDITION

¹Tsukuba International University, Department of Physical Therapy, Faculty of Health Sciences, Tsuchiura, Japan

Background: Falls among the elderly are a major public health concern. Recently, the evaluation of fall risk under dual-task conditions has attracted attention because it replicates the condition of falls that occur in daily life. A famous dual-task used to evaluate fall risk is one combining walking and a cognitive task, such as serial-7s. Elderly people with a greater reduction in gait speed under dual-task conditions have a higher fall risk in the future. However, this evaluation method itself had a dilemma, including fall risk, because this evaluation method requires walking.

Purpose: In this study, we investigated the kind of task in a sitting position (i.e., no fall risk) that could explain the reduction in gait speed in the dual-task condition.

Methods: Twenty-one young adults were recruited for the study. All subjects participated in walking and sitting tasks. The walking task consisted of single- and dual-walking tasks. In the single-walking task, subjects walked 12 m at a comfortable speed. In the dual-walking task, subjects were asked to repeatedly subtract 7, starting with a randomly chosen three-digit number (serial-7s) while performing the single-walking task. The evaluation indices of the walking task were gait speed (meter/second) and the speed of answering serial-7s (number/second). Subsequently, we calculated the dual-task cost for each index by using the following formula: [(single-task performance – dual-task performance) / single-task performance]. Additionally, the sitting task consisted of single- and dual-task. In the single-sitting task, the subjects repeated the knee flexion and extension for 30 s. The knee extension torque and the pace of repetitions were free; however, we instructed the subjects to be the same as possible. In the dual-sitting task, subjects performed serial-7s while performing the single-sitting task. The evaluation indices of the sitting task were the coefficient of variation of peak knee extension torque, and coefficient of variation of the pace of repetition. Dual-task costs were calculated for each index like in the walking task. Finally, all correlations between dual-task costs in walking and sitting tasks were determined using Pearson's correlation analysis.

Results: A significant correlation was found between the dual-task cost of gait speed in the walking task and the coefficient of variation of the pace of repetitions in the sitting task (p = 0.039, r = 0.453). In contrast, a significant correlation was not observed between the dual-task cost of gait speed in the walking task and the coefficient of variation of knee extension torque in the sitting task (p = 0.818, r = 0.053).

Conclusions: The dual-task cost of the pace of repetitions in the sitting task explains the dual-task cost of gait speed in the walking task.

Implications: Previous evaluation methods using walking had a fall risk. Our results suggest that instead of the walking task, the pace of repetitions in the sitting task may be used to assess fall risk. In the future, we will investigate the accuracy of the sitting task in predicting falls.

Funding acknowledgements: This research work was supported by the Grants-in-Aid for Young Scientists (21K17475. Representative: Takehide Kimura).

Keywords:
Fall
Dual-task
Fall risk

Topics:
Health promotion & wellbeing/healthy ageing/physical activity
Older people
Research methodology, knowledge translation & implementation science

Did this work require ethics approval? Yes

Institution: Tsukuba International University

Committee: Ethics Committee of Tsukuba International University

Ethics number: R03-10