Validity of an inertial sensor-based system for the assessment of spatio-temporal parameters in people with multiple sclerosis

Abstract

BackgroundGait variability in people with multiple sclerosis (PwMS) reflects disease progression or may be used to evaluate treatment response. To date, marker-based camera systems are considered as gold standard to analyze gait impairment in PwMS. These systems might provide reliable data but are limited to a restricted laboratory setting and require knowledge, time, and cost to correctly interpret gait parameters. Inertial mobile sensors might be a user-friendly, environment- and examiner-independent alternative. The purpose of this study was to evaluate the validity of an inertial sensor-based gait analysis system in PwMS compared to a marker-based camera system.MethodsA sample N = 39 PwMS and N = 19 healthy participants were requested to repeatedly walk a defined distance at three different self-selected walking speeds (normal, fast, slow). To measure spatio-temporal gait parameters (i.e., walking speed, stride time, stride length, the duration of the stance and swing phase as well as max toe clearance), an inertial sensor system as well as a marker-based camera system were used simultaneously.ResultsAll gait parameters highly correlated between both systems (r > 0.84) with low errors. No bias was detected for stride time. Stance time was marginally overestimated (bias = −0.02 ± 0.03 s) and gait speed (bias = 0.03 ± 0.05 m/s), swing time (bias = 0.02 ± 0.02 s), stride length (0.04 ± 0.06 m), and max toe clearance (bias = 1.88 ± 2.35 cm) were slightly underestimated by the inertial sensors.DiscussionThe inertial sensor-based system captured appropriately all examined gait parameters in comparison to a gold standard marker-based camera system. Stride time presented an excellent agreement. Furthermore, stride length and velocity presented also low errors. Whereas for stance and swing time, marginally worse results were observed.

Between-Day Reliability of the Gait Characteristics and Their Changes During the 6-Minute Walking Test in People With Multiple Sclerosis

“…41 In contrast to Hadouiri et al, 20 which measured the 6MWT gait characteristics with an electronic walkway system and an oval circuit of 24m, we evaluated gait characteristics using IMUs in a 25 to 30 m corridor. The advantage of using IMUs enables the evaluation of gait characteristics on a single gait cycle basis (although the turnings are not included in the final analysis), is reliable in the assessment of gait parameters in short walking 42 and allows detecting changes in gait characteristics in pwMS during the 6MWT. 10,16,18,43,44 Our results build upon the current knowledge by adding new variables to the domains measured by Hadouiri et al, 20 showing that variability, asymmetry, kinematics, and coordination gait domains are also reliable in pwMS during the 6MWT.…”

Innovative multidimensional gait evaluation using IMU in multiple sclerosis: introducing the semiogram

“…Inertial measurement units (IMUs) are small, lightweight wearable sensors that can be used to assess gait in MS both in routine clinical practice and at home for long-term physiological gait assessment ( 7 , 12 – 19 ). They have also been found useful to detect early changes in MS with clinically isolated syndromes ( 13 , 20 ), and parameters such as speed, step length, and step time are correlated with the severity of the disease ( 16 ).…”