Measuring Gait Stability in People with Multiple Sclerosis Using Different Sensor Locations and Time Scales

Area of Science:

• Biomedical Engineering
• Neuroscience
• Rehabilitation Science

Background:

• Local divergence exponent (LDE) is a common measure for assessing gait stability in people with multiple sclerosis (PwMS).
• Variations in LDE calculation methods can yield inconsistent results, impacting diagnostic accuracy.
• Understanding factors influencing LDE is crucial for reliable gait analysis in PwMS.

Purpose of the Study:

• To investigate the impact of different sensor placements (foot, trunk, lumbar spine) and LDE calculation time scales on discriminating PwMS from healthy individuals.
• To determine how fatigue, assessed by time (first, middle, last 30 strides), affects LDE measures.
• To analyze the relationship between Expanded Disability Status Scale (EDSS) scores and gait stability over time in PwMS.

Main Methods:

• 86 PwMS and 30 healthy participants completed a six-minute walk test wearing inertial sensors.
• LDE was calculated using short (~50% stride) and very short (~5% stride) time scales.
• Linear random intercepts models were used to assess group, time, and EDSS effects on LDE.

Main Results:

• Healthy participants demonstrated better perturbation compensation on longer time scales (trunk) and shorter time scales (foot).
• Sensor location and time scale significantly influenced the sensitivity of LDE in distinguishing PwMS.
• Gait stability measures varied depending on whether trunk or foot kinematics were analyzed.

Conclusions:

• Sensor location and the chosen time scale for LDE calculation are critical factors in gait stability assessment for PwMS.
• Future research should standardize LDE methodology, considering both sensor placement and temporal analysis.
• Accurate gait stability evaluation is essential for effective rehabilitation strategies for people with multiple sclerosis.