Recommended outcome measures for inpatient rehabilitation of multiple sclerosis are not appropriate for the patients with substantially impaired mobility

Background: In multiple sclerosis (MS) rehabilitation, most currently used outcome measures were validated in patients with a relapsing remitting MS and mild to moderate impairments. We aimed to assess whether these measures were also adequate in more impaired patients, frequently encountered in those with progressive MS (PMS). Methods: Outcome measurements were extracted from medical records of 229 patients with PMS undergoing 3 weeks of routine inpatient rehabilitation between 2011 and 2015. We assessed the acceptability of Nine-Hole Peg Test (9HPT), Timed 25-Foot Walk (T25FW), 2-Minute Walk Test (2MWT), Rivermead Mobility Index (RMI) and the Functional Independence Measure (FIM) by analysing their statistical distributions, concurrent validity by comparing Spearman correlations with pre-specified hypotheses, and responsiveness across impairment status by calculating standardized response means. Results: Our concurrent validity hypotheses were mainly satisfied. However, all outcome measures had skewed distributions, showed low variability, and thus were inadequately discriminative. Moreover, 9HPT was never responsive across the impairment states, whereas the T25FW was responsive for mildly impaired patients, and the 2MWT for mild to moderate MS, respectively. Generic multi-items measures such as RMI and FIM-motor were adequately responsive for all severity levels. Conclusions: Currently used outcome measures are inadequate for patients with impaired mobility, and there is a dire need of specifically designed outcome measures for routine care that are less burdensome and short-term responsive.