Association of prospective falls in older people with ubiquitous step-based fall risk parameters calculated from ambulatory inertial signals: retrospective observational data analysis study (Preprint)

Abstract

In recent years, researchers have been advocating for the integration of ambulatory gait monitoring as a complementary approach to traditional fall risk assessments. However, current research relies on dedicated inertial sensors that are fixed on a specific body part. This limitation impacts the acceptance and adoption of such devices.

Our study objective is two-fold: to propose a set of step-based fall risk parameters that can be obtained independent of the sensor placement using a ubiquitous step detection method, and to evaluate their association with prospective falls.

A re-analysis was conducted on the 1-week ambulatory inertial data from the StandingTall study, which was originally described by Delbaere et al. [1]. The data contained 301 community-dwelling older people and fall occurrences over a 12-month follow-up period. Using the ubiquitous and robust step detection method “SmartStep” which is agnostic to sensor placement, a range of step-based fall risk parameters can be calculated based on walking bouts of 200 steps. These parameters are known to describe different dimensions of gait (i.e. variability, complexity, intensity, and quantity). First, the correlation between parameters was studied. Then, the number of parameters was reduced through step-wise backward elimination. Finally, the association of parameters with prospective falls was assessed through a negative binomial regression model using the Area Under the Curve (AUC) metric.

The built model had an AUC of 0.69 which is comparable to models exclusively built on fixed sensor placement. A higher fall risk is noted with higher gait variability (coefficient of variance of stride time), intensity (cadence), and quantity (number of steps), and a lower gait complexity (sample entropy and fractal exponent).

These findings highlight the potential of our method for comprehensive and accurate fall risk assessments, independent of sensor placement. This approach has promision implications for ambulatory gait monitoring and fall risk monitoring using consumer-grade devices.

ACTRN12615000138583