Translation, reliability, and validity of the Norwegian version of the ABILHAND-NMD and the ACTIVLIM for Myotonic Dystrophy type 1.

PURPOSE: To translate ABILHAND-NMD and ACTIVLIM into Norwegian and assess their psychometric properties in adults with Myotonic Dystrophy type 1(DM1).

METHODS

ABILHAND-NMD and ACTIVLIM were translated into Norwegian through a standardized translation process. Psychometric properties of the translated questionnaires were tested. Intraclass correlation coefficient (ICC3.1) was used to assess test-retest reliability and Cronbach's α for internal consistency. The validity of the questionnaires was also assessed.

RESULTS

A total of 39 adults with DM1 were included. We found excellent test-retest reliability on ABILHAND-NMD (ICC 0.91) and ACTIVLIM (ICC 0.93). We found a good internal consistency of ABILHAND-NMD with Cronbach's α (95%CI) of 0.80 (0.69-0.88) and ACTIVLIM with Cronbach's α (95%CI) of 0.88 (0.82-0.93) An expert group of healthcare professionals and a pilot group reported good face and content validity. We found a high correlation between ABILHAND-NMD and ACTIVLIM (r = 0.75), p < 0.001 implying good convergent validity. ABILHAND-NMD and ACTIVLIM showed no floor effect, but a potential for ceiling effect.

CONCLUSION

The Norwegian versions of ABILHAND-NMD and ACTIVLIM are reliable and valid patient reported outcome measures for Myotonic Dystrophy type 1. The questionnaires are easy to administer as they take a short time to answer, and the participants reported no problems understanding the questions.