A method for calculating fall risk parameters from discrete stride time series regardless of sensor placement

Area of Science:

• Biomedical Engineering
• Gait Analysis
• Gerontology

Background:

• Traditional fall risk assessments lack real-life gait parameters.
• Inertial sensors offer gait-related fall risk parameters (FRP) but sensor placement affects compliance.
• The Smartstep method shows robustness in step detection across various conditions.

Purpose of the Study:

• To assess the convenience of the Smartstep method for calculating FRP from different sensor placements.
• To validate Smartstep's performance with waist and wrist-mounted inertial sensors.

Main Methods:

• 29 elderly participants performed a 6-minute walk test with an IMU on the waist and wrist.
• Smartstep estimated step times to compute FRP.
• Results were compared to foot-mounted sensors using precision, recall, RMSE, ICC, and limits of agreement.

Main Results:

• Smartstep achieved high precision (99.5%) and recall (95.9%) for step detection.
• Stride duration showed excellent agreement (ICC=0.91) and low error (RMSE=54 ms) for both placements.
• FRP calculations demonstrated good agreement across different sensor positions.

Conclusions:

• Smartstep is robust for calculating gait-related fall risk indicators from various body locations, including the wrist.
• This method facilitates ambulatory step measurements and fall risk assessment in the elderly.
• The findings support the use of Smartstep for user-friendly, real-world gait monitoring.