Cognitive and personality features in parkinson disease: 2 Sides of the same coin?

Objective: This study seeks to identify the possible relationship between certain executive functions and the main personality traits in 25 nondemented Parkinson disease (PD) patients. Background: Both the presence of cognitive changes-mainly concerning executive functions-and peculiar personality traits, such as low novelty seeking, moral rigidity, industriousness, or introversion, were fully documented in PD patients. Methods: Patients underwent the Tower of London test and Alternating Fluency tasks for planning abilities and cognitive flexibility to be assessed. Personality features were evaluated using the Big Five Adjectives checklist. Results: The study provided evidence of a significant correlation between the Tower of London and the Emotional Stability factor and between Alternating Fluencies and the Openness to Experience factor. Conclusions: The Tower of London test and the Emotional Stability factor may require filtering of irrelevant information, activation of inhibition mechanisms, and use of negative feedback. The Alternating Fluency tasks and the Openness to Experience factor may require the ability to switch set and to express flexible thoughts or opinions in daily life. These results indicate that cognitive and personality changes in PD may be different expressions of a common psychologic mechanism related to the dysfunction of the frontostriatal system.