Development and assessment of the inter-rater and intra-rater reproducibility of a self-administration version of the ALSFRS-R.

Objective: The Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) is widely applied to assess disease severity and progression in patients with motor neuron disease (MND). The objective of the study is to assess the inter-rater and intra-rater reproducibility, i.e., the inter-rater and intra-rater reliability and agreement, of a self-administration version of the ALSFRS-R for use in apps, online platforms, clinical care and trials.
Methods: The self-administration version of the ALSFRS-R was developed based on both patient and expert feedback. To assess the inter-rater reproducibility, 59 patients with MND filled out the ALSFRS-R online and were subsequently assessed on the ALSFRS-R by three raters. To assess the intra-rater reproducibility, patients were invited on two occasions to complete the ALSFRS-R online. Reliability was assessed with intraclass correlation coefficients, agreement was assessed with Bland-Altman plots and paired samples t -tests, and internal consistency was examined with Cronbach's coefficient alpha.
Results: The self-administration version of the ALSFRS-R demonstrated excellent inter-rater and intra-rater reliability. The assessment of inter-rater agreement demonstrated small systematic differences between patients and raters and acceptable limits of agreement. The assessment of intra-rater agreement demonstrated no systematic changes between time points; limits of agreement were 4.3 points for the total score and ranged from 1.6 to 2.4 points for the domain scores. Coefficient alpha values were acceptable.
Discussion: The self-administration version of the ALSFRS-R demonstrates high reproducibility and can be used in apps and online portals for both individual comparisons, facilitating the management of clinical care and group comparisons in clinical trials.
Competing Interests: Competing interests: LAB, CDS, HHGT, SMAGV, RPAVE and JMAV-M have nothing to disclose. MAvE received grants from the Netherlands Organization for Health Research and Development (Veni scheme), The Thierry Latran Foundation, Joint Programme – Neurodegenerative Disease Research (JPND) and the Netherlands ALS Foundation (Stichting ALS Nederland). He received travel grants from Shire (previously Baxalta) and serves on the medical ethical review board of University Medical Centre Utrecht. LHvdB reports grants from ALS Foundation Netherlands, grants from The Netherlands Organization for Health Research and Development (Vici scheme), grants from The Netherlands Organization for Health Research and Development (SOPHIA, STRENGTH, ALS-CarE project), funded through the EU JPND, personal fees from Shire (previously Baxalta), personal fees from Biogen, personal fees from Cytokinetics, other from Prinses Beatrix SpierFonds, other from Latran Foundation, outside the submitted work.
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