A novel infrared laser device that measures multilateral parameters of stepping performance for assessment of all risk in elderly individuals

Background and aims: Avoiding falls requires fast and appropriate step responses in real-life situations. We developed a step-tracking device that uses an infrared laser sensor for convenient assessment of stepping performance, including concurrent assessment of temporal and spatial parameters. In the present study, we created a new index for assessment of fall risk that uses step speed and accuracy measurements. The purpose of this study was to determine whether the new index could discriminate between elderly individuals with different risks of falling. Methods: One hundred and fifty-two community-dwelling elderly individuals (73.9 ± 4.6 years) participated and performed stepping tasks as quickly as possible on a plus-shaped mat in response to optical cues. The step-tracking device with the infrared sensor detected the motion and position of both legs in the step field. The device recorded temporal and spatial parameters, foot-off and foot-contact time, step length, and the percentage of correctly executed steps. We used the coefficients of a logistic regression model to develop "stepping-response score" based on the weighted sum of these temporal and spatial parameters. Results: The faller group had significantly worse stepping-response score than the non-faller group (p < 0.001). A stepwise logistic regression analysis demonstrated that stepping-response score was independently associated with falling (odds ratio = 0.15; p < 0.001). The ROC curve had a moderate AUC (0.73) for stepping-response score (sensitivity 73.0 %; specificity 69.7 %). Conclusions: This study indicates that the stepping-response score calculated from measurements obtained using the new step-tracking device can identify elderly individuals who are at a risk of falling.