Predicting the disease trajectory of mild cognitive impairment with the discrepancy between semantic and phonemic fluency performance

The aim of this study was to test the ability of semantic-phonemic performance discrepancy on verbal fluency scores to predict the progression of Mild Cognitive Impairment (MCI) to Alzheimer's disease (AD) during longitudinal follow-up. In addition to semantic-phonemic discrepancy, semantic and phonemic fluency scores were also examined in the same direction. In MCI, there are significant decreases in verbal fluency performances in contrast to healthy aging. A semantic-phonemic discrepancy occurs due to the most serious decline in semantic fluency and the absence of significant changes in phonemic fluency. It has been shown in previous studies that this discrepancy might be an important predictor for the progression of the disease. Our goal is to replicate these results in a Turkish sample. In this context, 134 healthy elderly and 125 individuals with MCI who were longitudinally followed up in the Neurosciences Department of Dokuz Eylül University Institute of Health Sciences were included in the study. In our retrospective study, verbal fluency test scores of the participants were followed up with a 12-month follow-up period. Verbal fluency scores of participants who had progressed from MCI to AD were analyzed with logistic regression. According to results, semantic fluency was found to be an effective tool in predicting the course of the disease. Phonemic fluency is effective in distinguishing healthy individuals from individuals diagnosed with MCI. However, it was observed that the semantic-phonemic discrepancy scores were not effective in predicting the course of the disease and only healthy individuals could be distinguished from those diagnosed with MCI.