Reliability, validity, and normative investigation of Persian version of a High-Level Language Test (BESS)

Abstract

Our study aimed at reliability, validity, and normative investigation of the Persian version of the High-Level Language Test (BESS). This study was conducted on 60 multiple sclerosis (MS) patients as well as 60 healthy individuals. After translating the BESS into Persian, its content validity was determined based on 10 experts working in the same field. The reliability of the test was determined using techniques such as the test–retest method, Cronbach's alpha, and clinical validity. The content validity ratio (CVR) was higher than 0.62 for every subtest, and the content validity index (CVI) was between 0.1 and 0.8 for all subtests. Cronbach's alpha coefficient was between 0.70 and 0.93, and intraclass correlation coefficient (ICC) was between 0.80 and 0.96. Clinical validity results showed a significant difference between means of patients’ scores and healthy subjects scores (p ≤ 0.005). The Persian version of BESS benefits from high reliability and validity values. Speech therapists can use the test to examine high-level language disorders in MS patients.