Variability of Multiple Sclerosis Walking Scale and Multiple Sclerosis Impact Scale Scores in People Without Multiple Sclerosis.

Introduction  Many people with multiple sclerosis (pwMS) experience problems with mobility at some point in their disease course. The Multiple Sclerosis Impact Scale (MSIS) and Multiple Sclerosis Walking Scale (MSWS) are validated patient-reported outcome measures of physical impairment in pwMS. The range of scores on MSIS and MSWS in people without MS (pwoMS) are not well understood. Methods People over the age of 16 who did not have a diagnosis of multiple sclerosis (MS) were invited to complete an online survey consisting of a general health questionnaire, MSIS and the MSWS. Scores for MSIS and MSWS from pwoMS were compared to those from a cohort of 35 pwMS from a previous study. Scores for MSIS and MSWS were correlated with age, sex and comorbidities in pwoMS. Results One hundred eighty-nine ambulant pwoMS were recruited (52.5% female), aged over 16 years of age. Ninety-nine percent reported no difficulty with walking, 89.4% were non-smokers, and 14% had a physical co-morbidity. None used a walking aid. For pwoMS, the MSIS score was a mean of 39.14±13.75 (range 29-127), compared to a mean of 77.2±24.94 (range 40-126) for pwMS. For pwoMS, the mean MSWS score was 8.46±16.2 (0-87) compared to a mean of 56.9±28.9 (4-100) for pwMS. There was no significant effect of sex or smoking on MSIS or MSWS scores in pwoMS. Presence of a physical co-morbidity was associated with significantly higher MSIS and MSWS scores in pwoMS. There was a significant correlation of increasing age with increasing MSWS score in pwoMS but no correlation of age with MSIS score. Conclusion There is a wide range of MSWS and MSIS scores in pwoMS. The age and presence of comorbidities influence both MSWS and MSIS scores. Our findings have implications for the selection of control groups for clinical studies in pwMS.