Introduction: Deficits in goal-directed behavior are common in individuals with Parkinson's disease (PD) and have been ascribed to apathy. In addition to apathy, individuals' beliefs in their competence (self-efficacy) and capacity to regulate emotions, thoughts, and actions (self-regulation) are critical skills for goal-directed behavior. We investigated these skills and their relationship to motor and non-motor symptoms in individuals with PD. We also examined the neural correlates of these skills using functional magnetic resonance imaging (fMRI).
Methods: We enrolled 35 subjects with mild PD (Hoehn and Yahr stage ≤2.5) and used the new general self-efficacy (NGSES) and self-regulation scales (SRS). We correlated the scores on these scales with measures of cognition, anxiety, depression, apathy, fatigue, quality of life, and disease burden using stepwise regression analyses. We collected resting-state fMRI data in a 3-Tesla scanner and computed the pairwise functional connectivity among nodes of major networks. We correlated the connectivity maps with the NGSES and SRS scores.
Results: Our PD cohort demonstrated intact NGSES and SRS scores compared with respective population data. These scores showed significant negative correlation with apathy and disease burden. Stronger connectivity in the salience network and decoupling from the default mode network supported self-efficacy and self-regulation.
Conclusions: Self-efficacy and self-regulation capacity seems preserved, but vulnerable to disease-related factors in individuals with mild PD. Educational programs cultivating this capacity could improve the coping skills of these individuals. Functional connectivity changes in salience and default mode networks may serve as neurobiological markers to demonstrate the effectiveness of such interventions.
Keywords: Apathy; Functional MRI; Neural networks; Parkinson’s disease.