Parkinson's disease (PD) is a neurodegenerative disorder involving the basal ganglia, resulting in motor and extra-motor deficits. These extra-motor deficits may be reflective of a self-regulatory deficit impacting patients' ability to regulate cognitive processes, thoughts, behaviors, and emotions. There is a need to further examine the prevalence and range of self-regulation (SR) and executive functioning (EF) impairments in PD. This study sought to do so in a sample of patients with PD (N = 31) who underwent deep brain stimulation (DBS) surgery for motor symptom treatment. Patients completed measures indicative of SR and EF including neurocognitive tests, heart rate variability (HRV), and self-report questionnaires to examine these constructs in PD. The highest prevalence of impairments were observed for total impulse control disorder (ICD) symptoms (74%), depressive symptoms (48%), verbal fluency (phonemic: 39%; semantic: 36%), mental flexibility (32%), and self-reported SR impairments (Metacognition: 32%; Behavioral Regulation: 29%). Correlations among theoretically related constructs (i.e., SR, EF) were modest and variable; challenging the idea that SR is a unitary construct for which different domains depend on a common resource. In patients with PD post-DBS, higher resting HRV, thought to be indicative of better autonomic functioning, was linked to better EF in some instances but not others and not significantly associated with self-report SR. Overall, patients with PD exhibit various extra-motor deficits, ranging from subtle to severe. Health care professionals working with patients with PD should recognize the presence of extra-motor deficits, particularly ICDs, and obstacles that might arise from such impairments in patients' daily lives.
Keywords: Deep brain stimulation; Executive functioning; Heart rate variability; Impulse control disorder; Parkinson's disease; Self-regulation.
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