Evaluation of reliability and validity of the Serbian Aphasia Screening Test

A rise in strokes worldwide means that the number of people affected by aphasia is increasing. Early and accurate diagnosis of aphasia is crucial for recovery. Presently, there are no dedicated screening tests tailored for evaluating aphasia in Serbian-speaking individuals. This paper presents and describes the psychometric properties of the Serbian Aphasia Screening Test (SAST), a novel aphasia screening tool designed specifically for Serbian speakers. This initiative fills the gap in aphasia assessment tools for the Serbian population, providing a comprehensive and culturally sensitive approach to the evaluation of language disorders.

Data using the SAST were collected from 240 participants: 120 Serbian speakers with aphasia after stroke compared to 120 neurotypical individuals. The assessment included the following subtests: conversation, verbal automatized sequences, auditory comprehension, visual confrontation naming, responsive naming, repetition of words, repetition of sentences, oral word reading, oral sentence reading, reading comprehension, and writing. The main objectives were to ascertain the psychometric qualities of the SAST, including inter-rater reliability of scoring, test-retest reliability, reliability of the individual subtests, overall test reliability, and inter-correlations among subtests. Additionally, the study evaluated the discriminatory capability of the SAST in distinguishing between individuals with aphasia and neurotypical controls, as well as between individuals with different types of aphasia.

The findings revealed that the SAST has excellent inter-rater reliability, test-retest reliability, and internal consistency. There were statistically significant differences between individuals with aphasia and neurotypical controls on all SAST subtests. Furthermore, the study identified significant differences in language profiles among participants with different types of aphasia. The significant correlations between scores on the SAST and on the Boston Diagnostic Aphasia Examination (BDAE) suggest good convergent validity of the SAST.

The results underscore the robust psychometric properties of this novel screening assessment (SAST) and its ability to effectively discriminate between diverse linguistic abilities within different aphasia syndromes in Serbian speaking individuals.