Inertial sensing of step kinematics in ambulatory patients with ALS and related motor neuron diseases

Abstract

Amyotrophic lateral sclerosis (ALS) is a progressive disorder which impairs gait and elevates the risk for falls. Current methods of assessing gait in these patients are infrequent and subjective. The goal of this study was to evaluate wearable-based methods for assessing gait to facilitating better monitoring of ambulatory health and ultimately lessen fall risk. Thirty ambulatory patients seen in ALS clinic were guided by a physical therapist on a short walk, during which inertial sensors recorded their movement. Two methods, utilising sensors at the waist or foot, were used independently to estimate gait parameters. Decreased stride length, increased stride duration and decreased walking speed were associated with lower functional walking scores, and the presence of a cane or walker. Overall, there was no group-wide mean walking speed differences between methods, though the waist method overestimated stride length and walking speed in those with more significant gait dysfunction compared to the foot method. Reconstruction of movement using the foot-based sensor resulted in route segments that were 94 ± 1% standard error of the mean (SEM) the length of a centre-to-centre hallway reference vector, with an angular error of 0.66 ± 0.28° SEM.

Keywords:

• Gait
• accelerometer
• gyroscope
• wearable
• ALS

Acknowledgements

The authors thank the clinic team, especially Victoria Kern, Teresa Kalinay and Pamela Hudson.

Disclosure statement

Zachary Simmons has received consulting fees from Biogen and Cytokinetics, research support from Biogen, Biohaven and Cytokinetics, and stipends from Wiley, Inc. The other authors report no conflicts of interest.

Additional information

Funding

This work was supported by the Penn State Clinical and Translational Sciences Institute through NIH/NCATS Grant Number UL1 TR000127 and UL1 TR002014.