The Persian version of the Functional Oral Intake Scale (FOIS-P): a validation study on stroke patients with dysphagia.

Purpose: The present study aimed to validate the Persian version of the Functional Oral Intake Scale (FOIS-P) for stroke patients.

Materials and methods: The current study was conducted in two phases: (1) translation and cross-cultural adaptation of the FOIS into Persian and (2) validation of the FOIS-P. Phase 1 included forward translation, synthesis, back-ward translation, expert panel, and pretesting. To validate the FOIS-P, inter-rater reliability, cross-validity, and sensitivity to change of the scale were investigated. To evaluate the inter-rater reliability of the FOIS-P, two speech-language pathologists, who were blind to the study aims and procedure, applied the FOIS-P to assess the oral intake of 60 stroke survivors. The cross-validity was assessed by investigating the correlation between the FOIS scores and the Video Fluoroscopy Swallowing Study (VFSS). Also, we applied the FOIS-P on 60 patients with stroke at three different times to investigate the sensitivity to change.

Results: Inter-rater reliability of the FOIS-P was excellent according to Cohen's Kappa calculation (K = 0.89, p<.001). Investigation of cross-validity showed that there were significant correlations between the FOIS scores and presence of dysphagia, presence of aspiration, and severity of dysphagia (p<.001). The changes of the FOIS-P scores over follow-ups revealed that the FOIS-P was sensitive to the patient's oral intake changes.

Conclusions: The FOIS-P is a valid and reliable tool for assessing oral intake in stroke survivors with dysphagia. Hence, the FOIS-P may be suitable for clinical and research in the field of stroke.