Background: The Patient Determined Disease Steps (PDDS) is a promising patient-reported outcome (PRO) of disability in multiple sclerosis (MS). To date, there is limited evidence regarding the validity of PDDS scores, despite its sound conceptual development and broad inclusion in MS research. This study examined the validity of the PDDS based on (1) the association with Expanded Disability Status Scale (EDSS) scores and (2) the pattern of associations between PDDS and EDSS scores with Functional System (FS) scores as well as ambulatory and other outcomes. Methods: 96 persons with MS provided demographic/clinical information, completed the PDDS and other PROs including the Multiple Sclerosis Walking Scale-12 (MSWS-12), and underwent a neurological examination for generating FS and EDSS scores. Participants completed assessments of cognition, ambulation including the 6-minute walk (6 MW), and wore an accelerometer during waking hours over seven days. Results: There was a strong correlation between EDSS and PDDS scores (ρ = .783). PDDS and EDSS scores were strongly correlated with Pyramidal (ρ = .578 & ρ = .647, respectively) and Cerebellar (ρ = .501 & ρ = .528, respectively) FS scores as well as 6 MW distance (ρ = .704 & ρ = .805, respectively), MSWS-12 scores (ρ = .801 & ρ = .729, respectively), and accelerometer steps/day (ρ = -.740 & ρ = -.717, respectively). Conclusion: This study provides novel evidence supporting the PDDS as valid PRO of disability in MS.

Background: Assessing walking impairment in those with multiple sclerosis (MS) is common, however little is known about the reliability, precision and clinically important change of walking outcomes. Objective: The purpose of this study was to determine the reliability, precision and clinically important change of the Timed 25-Foot Walk (T25FW), Six-Minute Walk (6MW), Multiple Sclerosis Walking Scale-12 (MSWS-12) and accelerometry. Methods: Data were collected from 82 persons with MS at two time points, six months apart. Analyses were undertaken for the whole sample and stratified based on disability level and usage of walking aids. Intraclass correlation coefficient (ICC) analyses established reliability: standard error of measurement (SEM) and coefficient of variation (CV) determined precision; and minimal detectable change (MDC) defined clinically important change. Results: All outcome measures were reliable with precision and MDC varying between measures in the whole sample: T25FW: ICC=0.991; SEM=1 s; CV=6.2%; MDC=2.7 s (36%), 6MW: ICC=0.959; SEM=32 m; CV=6.2%; MDC=88 m (20%), MSWS-12: ICC=0.927; SEM=8; CV=27%; MDC=22 (53%), accelerometry counts/day: ICC=0.883; SEM=28450; CV=17%; MDC=78860 (52%), accelerometry steps/day: ICC=0.907; SEM=726; CV=16%; MDC=2011 (45%). Variation in these estimates was seen based on disability level and walking aid. Conclusion: The reliability of these outcomes is good and falls within acceptable ranges. Precision and clinically important change estimates provide guidelines for interpreting these outcomes in clinical and research settings.

Purpose: This systematic review was conducted to provide rich and deep evidence of the perceived determinants and consequences of physical activity and exercise based on qualitative research in multiple sclerosis (MS). Method: Electronic databases and article reference lists were searched to identify qualitative studies of physical activity and exercise in MS. Studies were included if they were written in English and examined consequences/determinants of physical activity in persons with MS. Content analysis of perceived determinants and consequences of physical activity and exercise was undertaken using an inductive analysis guided by the Physical Activity for people with Disabilities framework and Social Cognitive Theory, respectively. Results: Nineteen articles were reviewed. The most commonly identified perceived barriers of physical activity and exercise were related to the environmental (i.e. minimal or no disabled facilities, and minimal or conflicting advice from healthcare professionals) and related to personal barriers (i.e. fatigue, and fear and apprehension). The most commonly identified perceived facilitators of physical activity were related to the environment (i.e. the type of exercise modality and peer support) and related to personal facilitators (i.e. appropriate exercise and feelings of accomplishment). The most commonly identified perceived beneficial consequences of physical activity and exercise were maintaining physical functions, increased social participation and feelings of self-management and control. The most commonly identified perceived adverse consequences were increased fatigue and feelings of frustration and lost control. Conclusions: Results will inform future research on the perceived determinants and consequences of physical activity and exercise in those with MS and can be adopted for developing professional education and interventions for physical activity and exercise in MS. Implications for Rehabilitation Physical activity and exercise behaviour in people with multiple sclerosis (MS) is subject to a number of modifiable determinants. Healthcare professionals working to promote physical activity and exercise in those with MS should choose to endorse the positive benefits of participation. Future physical activity interventions for those with MS may be improved by incorporating behavioural management strategies.

Much research has been undertaken to establish the important benefits of physical activity in persons with multiple sclerosis (MS). There is disagreement regarding the strength of this research, perhaps because the majority of studies on physical activity and its benefits have not undergone initial and systematic feasibility testing. We aim to address the feasibility processes that have been examined within the context of physical activity interventions in MS. A systematic scoping review was conducted based on a literature search of five databases to identify feasibility processes described in preliminary studies of physical activity in MS. We read and extracted methodology from each study based on the following feasibility metrics: process (e.g. recruitment), resource (e.g. monetary costs), management (e.g. personnel time requirements) and scientific outcomes (e.g. clinical/participant reported outcome measures). We illustrate the use of the four feasibility metrics within a randomised controlled trial of a home-based exercise intervention in persons with MS. Twenty-five studies were identified. Resource feasibility (e.g. time and resources) and scientific outcomes feasibility (e.g. clinical outcomes) methodologies were applied and described in many studies; however, these metrics have not been systematically addressed. Metrics related to process feasibility (e.g. recruitment) and management feasibility (e.g. human and data management) are not well described within the literature. Our case study successfully enabled us to address the four feasibility metrics, and we provide new information on management feasibility (i.e. estimate data completeness and estimate data entry) and scientific outcomes feasibility (i.e. determining data collection materials appropriateness). Our review highlights the existing research and provides a case study which assesses important metrics of study feasibility. This review serves as a clarion call for feasibility trials that will substantially strengthen the foundation of research on exercise in MS.