Investigation of Gait Initiation in Women With Multiple Sclerosis (MS)

Background: Walking impairment is one of the most reported symptoms of Multiple Sclerosis (MS). The documentation of gait impairments is important for indexing disease progression and rehabilitation in MS. By measuring and comparing relevant parameters based on the Center of Pressure (COP) patterns, this study aimed to characterize the execution of the gait task and to identify the relationship between these parameters and the level of Expanded Disability Status Scale (EDSS). Methods: Ten women with MS, with an average EDSS score of 2.4, and 10 healthy women were tested using a force plate and motion capture system during the transition from standing to gait posture. The time series of COP were acquired and processed to extract the trajectoryrelated parameters followed by the COP. Results: The correlation analysis underlined that the progressive alteration of the task execution is directly related to the increase in the EDSS score. These findings suggest that most of the impairments found in people with MS originate from the first part of the COP pattern: the anticipatory postural adjustments (APAs). Before every voluntary movement, the central nervous system performs APAs to minimize the balance perturbation due to the movement itself. Conclusion: Gait initiation APAs play a role in some contractions of ankle muscles and induce a backward COP shift to the swing limb. Our analysis highlighted that patients who affected by MS have a reduced posterior COP shift that reveals the impairment of the anticipatory mechanism.