Fluency tasks, e.g. verbal, design fluency test, etc. are often used in the evaluation of cognitive function in patients with schizophrenia. In the standard approach, the test result is the sum of stimuli generated in a given time period. However, this approach does not allow to determinate of what strategies are used by subjects to regulate the cognitive engagement during task execution.

To investigate the specific dynamic profile of fluency tests performance comparing with healthy controls.

Thirty patients diagnosed with schizophrenia and 30 demographically matched healthy controls took part in the study. Participants performed two tests: COWAT (3 trials) and Ruff Figural Fluency Test in accordance with the original instructions. During the generation of these stimuli, the investigator wrote down their quantity in 15-second intervals, which enables the assessment of cognitive engagement variability in different parts of the whole time (1minute).

Comparison of cognitive engagement variation in both fluency tests showed statistically significant differences. The differences in repeated measures ANOVA with group as an independent variables reached P<0.0001. Factor differentiating the profiles in verbal and figural fluency was first 15seconds after the tasks started.

The beginning of task was the most difficult part for patients with schizophrenia, which may indicate that the overall worse performance of fluency tests is associated with significant difficulties in mobilizing the cognitive activity.