Spanish adaptation of the revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R)

Abstract

ALSFRS-R is a tool designed to measure disease progress in ALS patients. It consists of 12 items grouped into four functions designed to assess disabilities according to the Activities of daily living (ADL). Our objective was to validate the Spanish version of ALSFRS-R based on the original version. Four examiners assessed 73 ALS patients, applying the ALSFRS-R, ALSAQ-40 and the respiratory function variable assessed by the SRI scale, which measures respiratory insufficiency. Internal consistency and test-retest correlations were measured using Cronbach's alpha and Spearman's Rho tests. Factor analysis was performed by applying Varimax rotation and Kaiser standardization. Validity was analysed based on correlations between items in the ALSFRS-R scales and equivalents in the ALSAQ-40 and SRI questionnaires. The results showed high internal consistency (0.77–0.95) and a good test-retest correlation (0.80–0.95). Factor analysis showed a 73.3% principal component contribution; the weight of each item regarding their corresponding factors was 0.7–0.9. High correlations were observed (rs >0.60) between corresponding factors of ALSFRS-R/ALSAQ-40 and ALSFRS-R/SRI. We conclude that the version obtained from the ALSFRS-R maintains the internal consistency and validity of the construct of the original scale.

The Spanish version of ALSFRS-R is available for readers at http://www.fundela.es/verOtras.php

Key words::

• Amyotrophic lateral sclerosis
• ALSFRS-R scale
• Spanish version
• assessment questionnaires
• quality of life

Acknowledgements

The authors of this study wish to express their gratitude to R. Ferrando, M. Brito and J.M. Echave for their invaluable assistance in this project.

Declaration of interest: This work was supported by the Spanish Foundation for the Investigation's Promotion of the Amyotrophic Lateral Sclerosis (FUNDELA).