Multi-Modal Measurement of Fatigue-Induced Gait Changes in a Person with Multiple Sclerosis during a 12-Minute Walk Test

Background: Motor fatigability, a measurable change in performance with sustained activity, may result in changes in gait in people with multiple sclerosis (MS). The use of a single measuring mode may be inadequate to identify the gait deviations that may be most amenable to rehabilitation.  A combined model that examines both temporal-spatial and kinematic measures during prolonged walking may enable clinicians to better assess these changes.

Objectives: To examine changes in gait induced by motor fatigability by comparing temporal-spatial and kinematic parameters during the 1st and 12th minutes of a 12-minute walk test (12MWT). We hypothesized that temporal-spatial and kinematic measures would change between the first and last minutes of the 12MWT.

Methods: The participant was a 65-year-old woman with relapsing-remitting MS (Disease Steps = 3; Patient-Determined Disease Steps = 4) who underwent a 12MWT along a modified pathway (a short oval track) with an instrumented walkway (CIR Systems, Sparta, NJ) laid over one straightaway. Temporal-spatial gait measures were recorded and analyzed with PKMAS Gait Analysis Software (Protokinetics, Inc., Havertown, PA). Kinematic data were collected for peak range of motion at the bilateral ankles, knees and hips with an 8-camera (Vicon Motion Systems Ltd. UK) 3-D motion capture system and interpreted with Motion Monitor software (Innovative Sports Training, Inc., Chicago, IL). Mean values were calculated for all recorded walking strides during the 1^st and 12^thminutes of the 12MWT.

Results: From the first to the last minute of the 12MWT, this participant had notable declines in mean values of walking velocity and step length, and increases in cadence and in step-to-step variability of step length, step time, stride velocity, single-limb support time and swing time. The most notable changes in kinematics included reduced peak right hip flexion and extension, bilateral ankle plantarflexion and hip abduction, and variability in left ankle dorsiflexion.

Conclusions: The purpose of this case report was to describe the impact of motor fatigability induced by prolonged walking on temporal-spatial parameters of gait and LE kinematics in a person with MS. This case report demonstrates that a notable deterioration in gait may be experienced by people with MS during prolonged walking. This case also exemplifies the use of a multi-modal gait analysis to well-describe these changes. For example, one hypothesis that emerges from this data is that this person’s diminished step length and velocity may be attributed to reduced peak right hip flexion/extension and bilateral ankle plantarflexion. Further research should be conducted using similar multi-model analysis to acquire a richer and more granular description of the impact of motor fatigability on walking during prolonged activity in people with MS.