Translation, and validation of Dysphagia Outcome and Severity Scale (DOSS): Swedish version

Swallowing dysfunction (dysphagia) significantly impacts patient and medical outcomes. In Sweden, there is no comprehensive outcome measure for dysphagia that incorporates holistic assessment and dysphagia impact on a person's impairment, function and participation. The Dysphagia Outcome and Severity Scale (DOSS) was developed and validated (in English) and incorporates the World Health Organisation's (WHO) aforementioned, International Classification of Functioning (ICF) aspects. This study translated then evaluated the validity and reliability of the Swedish version, DOSS-S.

Translation occurred based on WHO recommendations. The Content Validity Index (CVI) of the translated version (DOSS-S) was assessed twice by 11 (multi-professional) dysphagia experts. Criterion validity and rater reliability was calculated using 18 Speech Pathologists assessing patient cases from International Dysphagia Diet Standardization Initiative-Functional Diet Scale (IDDS-FDS) research.

Very high CVI values (0.96-0.99) for the linguistic correlation, and high CVI values (0.84-0.94) for applicability correlation were achieved. High criterion validity of DOSS-S with IDDSI-FDS was demonstrated (r_s = 0.89, p < 0.01), with very high inter and intra rater reliabilities (ICC > 0.90).

The DOSS-S demonstrated very high validity values, and very high inter and intra rater reliability. This research contributes to improved dysphagia management by providing interprofessional dysphagia clinicians with a validated scale to identify patient progression, communicate dysphagia status between regions and countries, and document patient outcomes using an ICF framework.