Validity, Reliability and Standardization Study of the Language Assessment Test for Aphasia

Objective: Aphasia assessment is the first step towards a well-founded language therapy. Language tests need to consider cultural as well as typological linguistic aspects of a given language. This study was designed to determine the standardization, validity and reliability of Language Assessment Test for Aphasia, which consists of eight subtests including spontaneous speech and language, auditory comprehension, repetition, naming, reading, grammar, speech acts, and writing. Material and Method: The test was administered to 282 healthy participants and 92 aphasic participants in age, education and gender-matched groups. The validity study of the test was investigated with analysis of content, structure and criterion-related validity. For reliability of the test, the analysis of internal consistency, stability and equivalence reliability was conducted. The influence of variables on healhty participants' sub-test scores, test score and language score were examined. According to significant differences, norms and cut-off scores based on language score were determined. Results: The group with aphasia performed significantly lower than healthy participants on subtest, test and language scores. The test scores of the healthy group were mostly affected by age and educational level but not by gender. According to significant differences, age and educational level for both groups were determined based on. Considering age and educational levels, the reference values for the cut-off scores were presented. Discussion: The test was found to be a highly reliable and valid aphasia test for Turkish-speaking aphasic patients either in Turkey or other Turkish communities around the world.