Portuguese translation and cultural adaptation of the self-administered amyotrophic lateral sclerosis functional rating scale – revised

Abstract

Objectives: Amyotrophic Lateral Sclerosis (ALS) is a progressive neurological disease whose number of cases in Portugal and in the rest of the world is increasing, being a condition increasingly studied in the scientific world. In Portugal, there are no available validated screening tools for this condition. This study aims to translate and validate the “Self-Administered Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised” (Self-administered ALSFRS-R) to the European Portuguese language (EP). Methods: The English version of the Self-administered ALSFRS-R was translated into EP, by a bilingual translator and a speech and language therapist. A common version was agreed. Back translation was completed by a bilingual teacher. A panel of experts, composed of several health professionals with experience in the area, analyzed this version, and classified all its items in terms of relevance, clarity, ambiguity and conceptual adequacy (phase I). Some modifications were suggested and incorporated. The new version was reanalyzed by the same group (phase II). Data resulting from both phases were statistically analysed using the Content Validity Index (CVI). A pilot test was performed with 12 people with ALS and the internal validity was obtained. Results: Results obtained from phase II show high agreement between all experts regarding the clarity (CVI phase I=92%; phase II=100%), ambiguity (CVI phase I=92%; phase II=100%), relevance (CVI phase I=92%; phase II=100%) and adequacy of the concepts (CVI phase I=92%; phase II=100%), and for the overall score (phase I=83%; phase II=100%). In the pilot study, the internal consistency result was also very high (Cronbach’s α = 0.92). Conclusions: The Self-administered ALSFRS-R Portuguese version presented good values for content validity and internal consistency. It is therefore possible to use this instrument at various stages of the disease and to determine the degree of functionality of the Portuguese patients. Further studies are needed in order to analyze its psychometric characteristics.