Reliability and validity of the Slovenian Translation of the Functional Oral Intake Scale (FOIS-SI)

Abstract

Background: It is crucial that each and every stroke patient gets a systematic assessment of swallowing disorders, performed by a dysphagia specialist. Therefore, there is a need to use a standardized scale among professionals. The aim of this study was to translate, adapt, and obtain the statistical characteristics of the Functional Oral Intake Scale (FOIS), which is an observer-rated dysphagia severity scale primarily developed for stroke patients, into the Slovenian language.
 Methods: We performed a 5-step translation and adaptation process. Six speech and language pathologists had evaluated 30 clinical records of patients with an acute ischemic stroke in the carotid artery territory with the Slovenian translation of the Functional Oral Intake Scale (FOIS-SI). Every clinical record included a speech and language clinical bedside assessment of dysphagia, the sex, age, National Institutes of Health Stroke Scale (NIHSS), comorbidities of patients and lesion location. We examined interrater and intrarater reliability and additionally convergent validity of FOIS-SI with the theoretically related IDDSI-Functional Diet Scale (IDDSI-FDS).
 Results: The average measure Intraclass Correlation Coefficient (ICC) for the interrater reliability (ICC=0.959) and the intrarater reliability (ICC=0.979 and ICC=0.991) for both raters was excellent. The FOIS-SI scores correlated very high with the IDDSI-FDS (rs=0.927).
 Conclusion: The results of this study show that the Slovenian translation of the FOIS has an excellent interrater and intrarater reliability and very high validity, which implies the FOIS-SI can be used as a tool to quantitatively assess the severity of dysphagia in clinical practice and research in patients with stroke in carotid artery territory across the country in all medical and care settings.