Online

VanNostrand, Michael

Rehabilitation and Movement Science

2023

Ph. D.

The neurodegeneration caused by multiple sclerosis (MS) results in a progressive decline in functioning and quality of life. Mobility impairment is often reported as the most common symptom affecting people with the disease, contributing to about 50% of the population reporting at least one fall in any three-month period. Although the underlying cause of falls in persons with MS is multifaceted, there is mounting evidence that the inclusion of a cognitive task during walking (dual tasking) leads to increased fall risk. Previous research in lab-based environments has highlighted the association between dual task walking and increased stride variability and decreased gait speed, leading to an increase in falls for persons with MS. While there is mounting evidence that dual task walking in the lab can differentiate between fallers and non-fallers with MS, these findings have not translated into acceptable clinical assessments. These assessments notably lack ecological validity, as they fail to consider key real-world factors, such as concurrent cognitive tasks, movement quality examination, and postural transitions and turns - all of which are problematic for those with MS. Additionally, changes in real-world ambulation are often attributed to mobility impairment, yet previous research underscores cognition and fear of falling as vital metrics impacting walking. Understanding contributors to real-world mobility is crucial, as they are necessary for both walking and community participation. Therefore, the objective of this project was to: 1) Examine the sensitivity and specificity of both currently used and novel clinical measures at predicting fall status in persons with MS 2) Identify a clinical assessment that is reflective of everyday walking in individuals with MS and 3) Examine the contributions of cognition, ambulation disability, and psychosocial factors to real-world gait quality and quantity. A total of 27 participants with MS, ranging in age from 40 to 75, were included in the study and underwent cognitive testing. Upon completion, participants performed a series of walking assessments, including the timed up and go (TUG), and three novel clinical assessments: TUG-extended, 25-foot walk and turn, and figure-8 walk. During the performance of the novel assessments, participants concurrently engaged in a verbal fluency cognitive task. At the conclusion of the in-lab session, participants in the study had an inertial sensor placed on their lower back, which they wore in the real world for three days. Results from the study showed that one of the novel clinical assessments, the 25-foot walk and turn, exhibited increased sensitivity and specificity compared to currently used clinical assessments. Furthermore, the 25-foot walk and turn was the assessment with the highest correlation to real-world captured measures of gait speed and stride variability. Finally, both cognition, namely processing speed, and ambulation disability significantly contributed to real-world measures of gait speed and stride variability. The findings highlight the significance of incorporating cognition into walking assessments for individuals with MS. Cognition emerged as a notable factor impacting real-world measures of gait speed and stride variability. Moreover, integrating cognition into clinical mobility evaluations enhanced ecological validity and ultimately improved the effectiveness at identifying fall status when compared to existing assessments.