Validity and reliability of the Turkish version of "the Dyspnea-ALS-Scale (DALS-15)"

Abstract

Aim The aim of this study was to investigate the validity and reliability of the Turkish version of The Dyspnea-ALS-Scale (DALS-15). Methods Forward translation, back translation, and cross-cultural adaptation were used to ensure the equivalency of translated version of the scale. Then, patients with amyotrophic lateral sclerosis (ALS) who have dyspnea or orthopnea that develops with effort or at rest were evaluated using DALS-15 via online surveys. The respiratory subscale of ALS Functional Rating Scale-Revised (ALSFRS-R) and Modified Borg Dyspnea Scale (MBDS) was used to investigate the construct validity of the Turkish DALS-15. Reliability was assessed with Cronbach's alpha and inter-item correlation matrix (internal consistency). Results We have included 52 ALS patients in the study. Findings showed that Turkish version of DALS-15 was highly correlated with respiratory subscale of ALSFRS-R (r = - 0.668; p = < 0.0001) and MBDS (for upright position: r = 0.728; p = < 0.0001 and for supine: r = 0.78; p = < 0.0001). The scale did not show any ceiling or floor effect. Also, DALS-15 had a high level of Cronbach's alpha (0.95) and internal consistency (ICC: 0.949; 95%CI: 0.92-0.96). Test-re-test reliability of the questionnaire was (ICC: 0.909; 95% CI: 0.81-0.95). The standard error of measurement value was 2.76, whereas the minimal detectable change score was 7.66 points for the translated version of the scale. Conclusions The Turkish version of DALS-15 possesses strong psychometric properties with excellent validity and reliability. It is shown to be useful for online self-assessment, outside of the clinical settings, especially in hard times such as a pandemic.