Adaptive Locomotor Performance in the Early Stages of Multiple Sclerosis: A Pilot Study

Background: Maintaining and improving mobility is one of the major goals in the rehabilitation of individuals diagnosed with Multiple Sclerosis (MS). A major component of mobility includes the ability to walk safely and independently in one’s natural environment. Challenges commonly encountered in natural environment (e.g. increasing walking speed, dual-tasking, etc.) require adaptations to walking parameters in order to prevent loss of balance and achieve safe walking. 

Objectives: 1) To compare performance of individuals in the initial stages of MS to age-matched healthy persons on adaptive locomotor tasks (ALT) that impose specific challenges, and 2) To examine the ability to integrate appropriate sensory systems in order to compensate for sub-optimal sensory information while performing ALT.

Methods: Individuals in the initial stages of MS (PDDS ≤ 3) and healthy controls (age and sex-matched) walked along a 6 meter path during four ALTs (obstacle crossing, narrow walking, walking-while-talking, and fast walking) and a control condition (self-selected normal walking). Visual information was intact or sub-optimal using custom-made blurring goggles. A motion capture system tracked body segment position and step characteristics. Following the walking tasks, participants completed a sensorimotor assessment which included: leg extensor strength, ankle proprioception, visual contrast sensitivity, and standing balance. 

Results: Preliminary findings demonstrate that individuals in the initial stages of MS had faster walking speeds compared to healthy controls in general. They were also able to increase walking speed on demand similar to healthy controls during fast walking. However, individuals in the initial stages of MS had reduced medio-lateral stability during the ALTs when compared to healthy controls. 

Conclusions: Our preliminary findings suggest individuals in the initial stages of MS, compared to healthy controls, have reduced stability during environmental challenges while walking. This instability occurs despite good walking abilities. Findings demonstrate that reduced postural control during walking can occur at the early stage of the disease, before mobility-related disability arises. Detailed findings of segmental control and step characteristics will be presented.