Validity, reliability and standardization study of Language Assessment Tool for Aphasia Administered to Healthy People & People with Aphasia due to Stroke

Aphasia assessment is the first step towards a well- founded language therapy. Language tests need to consider more detailed facts in 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 Tool for Aphasia (ADD), which consists of eight subtests including spontaneous speech and language, auditory comprehension, repetition, naming, reading, grammar, pragmatics (use of speech acts), and writing.The ADD was administered to 282 healthy participants and 92 aphasic participants in matched age, education and gender groups. Aphasic group performed highly lower than other participant groups on subtest, test and language scores. The ADD scores of healthy group were mostly affected by age and educational level but not affected by gender. According to significant difference, age and educational level groups were determined. Considering age and educational levels, the reference values for the cut-off scores were presented. Aphasic group was significantly different from healthy group on the ADD scores. A factor analysis disclosed 3 factors that explained 90.8% of the total variance. Reliability study results confirmed that the ADD is a highly reliable test. The ADD scores of aphasic participants were not affected much from age, educational level, gender, post onset, and types of aphasia.The ADD 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.