Limits of Verbal Fluency Tests Use in the Differential Diagnostic of Neurological Diseases

Verbal fluency tests are simple assessments evaluating patients' mental flexibility, ability to organize information into semantically similar groups, effective recall strategies and quality of working memory. Based on the results of research into brain imaging and functional brain imaging methods, experts assume that, while frontal lobe lesions are linked to rather inconsistent performance patterns in phonemic verbal fluency, temporal lobe lesions are more related to deficits in semantic verbal fluency. The aim of our study was to verify validity of these findings in routine clinical psychological practice during differential diagnostic procedure in the area of specific neurological disorders. Four groups of patients were included in the study: patients with frontal lobe epilepsy, two groups of patients with temporal lobe epilepsy left and right hemisphere, and patients with Parkinson's disease. Each group consisted of 25 patients. Statistical analysis was performed using the nonparametric Kruskal-Wallis test. The results showed no statistically significant differences in the scores of semantic and phonemic verbal fluency between the groups.