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.

The Multiple Sclerosis Outcome Assessments Consortium (MSOAC) includes representatives from advocacy organizations, Food and Drug Administration (FDA), European Medicines Agency (EMA), National Institute of Neurological Disorders and Stroke (NINDS), academic institutions, and industry partners along with persons living with multiple sclerosis (MS). One of the MSOAC goals is acceptance and qualification by regulators of performance outcomes that are highly reliable and valid, practical, cost-effective, and meaningful in MS. This article addresses the history, application, and psychometric properties of one such MSOAC metric of ambulation or walking namely, the timed 25-foot walk (T25FW). The T25FW has strong reliability over both brief and long periods of time in MS across a large range of disability levels. The outcome of walking speed from the T25FW has obvious real-world relevance and has correlated strongly with other measures of walking and lower extremity function. The T25FW is responsive for capturing intervention effects in pharmacological and rehabilitation trials and has an established value for capturing clinically meaningful change in ambulation. Directions for future research involve validating clinically meaningful improvements on the T25FW as well as determining whether 20% change is clinically meaningful across the disability spectrum. Researchers might further consider synchronizing accelerometers and motion sensors with the T25FW for capturing walking speed in everyday life and the patient’s real environment.

Objectives: To provide clinicians who treat multiple sclerosis (MS) patients with evidence-based or expert opinion–based recommendations for promoting exercise and lifestyle physical activity across disability levels. Methods: The National MS Society (“Society”) convened clinical and research experts in the fields of MS, exercise, rehabilitation, and physical activity to (1) reach consensus on optimal exercise and lifestyle physical activity recommendations for individuals with MS at disability levels 0–9.0 on the Expanded Disability Status Scale (EDSS) and (2) identify and address barriers/facilitators for participation. Recommendations: Based on current evidence and expert opinion, the Society makes the following recommendations, endorsed by the Consortium of Multiple Sclerosis Centers: Healthcare providers should endorse and promote the benefits/safety of exercise and lifestyle physical activity for every person with MS. Early evaluation by a physical or occupational therapist or exercise or sport scientist, experienced in MS (hereafter referred to as “specialists”), is recommended to establish an individualized exercise and/or lifestyle physical activity plan. Taking into account comorbidities and symptom fluctuations, healthcare providers should encourage ⩾150 min/week of exercise and/or ⩾150 min/week of lifestyle physical activity. Progress toward these targets should be gradual, based on the person’s abilities, preferences, and safety. If disability increases and exercise/physical activity becomes more challenging, referrals to specialists are essential to ensure safe and appropriate prescriptions. When physical mobility is very limited, exercise should be facilitated by a trained assistant.