Objective: The revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) is the most commonly used outcome measure in ALS studies. The aim of this study was to identify potential limitations of the ALSFRS-R from the perspective of people living with ALS and their caregivers.
Methods: A web-based survey was developed by investigators, people living with ALS, and their caregivers, and shared across social media. For each item, participants were asked, "Can you think of a situation where you might not be able to answer this item accurately or that your answer might not reflect your abilities?" Responses were divided into two categories: criticisms that could be addressed in a manual or issues with the items/responses that would require measure modification.
Results: 57 participants (72% participants with ALS, 28% caregivers) responded to at least one item question, of which 71.9% expressed concern about at least one item. The most frequently identified items were speech, walking, and cutting food. Common criticisms were: language used is of a medical literacy level too high; item is situational; difficult to distinguish the difference between response choices; and the structure and/or underlying assumptions of the item makes it difficult to answer.
Conclusions: Several items of the ALSFRS-R were considered to inaccurately reflect the abilities of patients with ALS. The ALSFRS-R may need a revision to address these issues, preferably in co-development with people living with ALS and their caregivers, and/or alternate outcome measures should be considered for patients with ALS.
Keywords: amyotrophic lateral sclerosis; clinical outcomes; measurement; qualitative study.