Development and longitudinal evaluation of ALSFRS-R-SE version 2.1 for remote digital self-assessment

Abstract Background The self-explanatory version of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R-SE) was developed to enable standardized assessment without a trained interviewer (version 1.0). However, it needed further refinement to better support longitudinal remote digital self-assessment. Methods Following a structured, consensus-based revision in both German and English, we analyzed remote assessments from the ALS App collected between March 2024 and July 2026. Using linear regression, we estimated the slope of the total score before the transition, the immediate change, and the change in slope for 189 participants. In the predictive analyses, the effects on 12 items and 48 response boundaries were evaluated for 420 participants. Results The combined word count decreased by 16.0% in German and by 23.6% in English. The reductions were particularly pronounced in the introductory text and in the response descriptions. V2.1 also showed structural simplification, including fewer parenthetical insertions. At the time of the transition, the total score change was − 0.062 points (95% CI − 0.303 to 0.184) and the change in slope was + 0.186 points/month (− 0.054 to 0.420). The item effects ranged from − 0.040 to + 0.036 points, with all confidence intervals containing the value zero. None of the 48 response boundary effects remained significant after correction for the false discovery rate. Conclusion ALSFRS-R-SE version 2.1 provides more concise wording and substantially reduces textual burden. Longitudinal analyses supported measurement continuity, showing no detectable systematic discontinuity in total or item scores and no response-boundary effects across the observed V1.0 to V2.1 transition in remote digital self-assessment.