Can Phonemic Verbal Fluency Be Used to Predict Alzheimer's Disease?

Background: Among the cognitive markers, the deterioration of semantic and phonemic verbal fluency seems to be an early indicator of Alzheimer's disease (AD). The aims of this study are (1) to evaluate both types of verbal fluency in the early stages of AD in order to know which of them deteriorates earlier and (2) to investigate if verbal fluency tasks can help to differentiate between patients with Mild Cognitive Impairment (MCI) who will progress to AD two years later (progress) and those who will not (non-progress).

Method: A verbal fluency task was administered to 25 patients with MCI and their respective control subjects. All patients underwent a neuropsychological evaluation twice in order for us to follow up on their global cognitive status. The second time, eight of them converted to AD.

Results: On the one hand, phonemic verbal fluency deteriorates earlier than semantic verbal fluency in MCI patients; on the other hand, although we found statistically significant differences between patients with MCI and AD in both types of fluency tasks, none were found when comparing the performance of progress and non-progress.

Conclusions: These results point to a greater impairment in phonemic verbal fluency in MCI patients and its potential capacity to predict conversion to AD.