Metric characteristics of BNVR – the Butt non-verbal reasoning test

Aphasia is an acquired communication disorder that presents in people with brain damage, with brain stroke and traumatic head injury as the most common causes. It affects speech, language comprehension, reading and writing. In the diagnostic process, the speech and language therapist (SLP) evaluates the individual’s linguistic and communication capacity with the help of clinical observation as well as standardised and non-standardised tests. A thorough diagnostic evaluation enables them to plan the appropriate rehabilitation goals. Aphasia can be accompanied by further disorders whose identification is a crucial part of diagnostics, as they impact rehabilitation. The most common co-morbid disorders are attention, memory, perception, cognition and problem-solving deficit disorders. In order to identify problems in the field of problem solving, the identification of which is highly significant in setting rehabilitation goals and understanding the progress of the individual, authors Butt and Bucks (2004) formed the BNVR – The Butt Non-Verbal Reasoning Test that is specifically designed to evaluate problem-solving abilities in persons with aphasia. This Master’s thesis assesses the suitability of the test for use in the Slovenian cultural space and determines potential needs for changing the test material. The measurement characteristics of the test were tested in 102 subjects of the typical Slovenian population without neurological problems and in 17 persons with aphasia. The result analysis showed that representatives of the typical population and representatives of the group of people with aphasia achieved 9.78 and 7.41 points on average, respectively. There is a statistically significant difference in the results of the general and the clinical sample. No differences in test results were determined between the sexes in either sample, but a statistically significant difference was observed in the age of the typical population, which is most likely a consequence of the general age-related decline of problem-solving abilities. A group of 11 expert confirmed the substantive validity of the test. In the analysis of the following measurement characteristics, we focused on the results of the clinical sample. We established a medium level of reliability (α = 0,66) and suitable discrimination (δ = 0,88). Regarding the discrimination value of individual testing tasks, we were able to classify most of the tasks as very good, two as good and one (Task 3) as unsuitable. 6 of 10 tasks reached a suitable difficulty level, 3 are too easy yet still within the limits of the broader criterion of recommended difficulty indexes, whereas Task 6 proved to be too difficult. The correlations between testing tasks reached a satisfactory level of homogeneity, despite not proving to be statistically significant. Task 3 stood out with negative correlations. Lastly, we analysed the distractors in individual tasks. We did not find statistically significant differences in the distractors in the general sample, yet the visual distractor in Task 3 still negatively stands out. In difference to the general sample, we determined two statistically significant differences in the choice of distractors in the clinical sample, namely in Tasks 3 and 6. Despite certain limitations, mainly the small clinical sample size, we concluded that the test is an appropriate tool for use in the Slovenian cultural space and indicated the need for a careful interpretation of the results of Task 3, or alternatively the need for a change thereof