Walking measures to evaluate assistive technology for foot drop in multiple sclerosis: A systematic review of psychometric properties

Background Foot drop in people with multiple sclerosis (pwMS) often managed with assistive technologies, such as functional electrical stimulation and ankle foot orthoses. No evidence synthesis exists for the psychometric properties of outcomes used to evaluate the efficacy of these interventions. Objective This systematic review aimed to identify the outcome measures reported to assess the benefits of assistive technology for pwMS and then synthesize the psychometric evidence in pwMS for a subset of these measures. Methods Two searches in eight databases were conducted up to May 2017. Methodological quality was rated using the COSMIN guidelines. Overall level of evidence was scored according to the Cochrane criteria. Results The first search identified 27 measures, with the 10 m walk test, gait kinematics and Physiological Cost Index (PCI) most frequently used. The second search resulted in 41 studies evaluating 10 measures related to walking performance. Strong levels of evidence were found for the internal consistency and test-retest reliability of the Multiple Sclerosis Walking Scale-12 and for the construct validity for Timed 25 Foot Walk. No psychometric studies were identified for gait kinematics and PCI in pwMS. There was a lack of evidence for measurement error and responsiveness. Conclusion Although a strong level of evidence exists for some measures included in this review, there was an absence of psychometric studies on commonly used measures such as gait kinematics. Future psychometric studies should evaluate a wider range of walking related measures used to assess the efficacy of interventions to treat foot drop in pwMS.