Psychophysiological mechanisms in Parkinson disease with Impulse Control Disorder (ICD) during a gambling task (IGT): a fNIRS-EEG study

Parkinson’s Disease (PD) is a neurodegenerative disorder characterized by a progressive depletion of dopamine systems which leads to clinically motor symptoms such as bradykinesia, rigidity and rest tremor. Moreover, cognitive and behavioral disturbances could affect some type of PD patients with cognitive and emotional affective symptoms as anxiety and depression. Recent studies have shown that the dopaminergic therapy can induce changing in executive functioning and lead to Impulse Control Disorders (ICDs) such as pathological gambling, hypersexuality, compulsive shopping and compulsive eating. There are some risk factors and potential mechanisms for the development of ICD including personality traits, potential genetic influences and parkinson’s disease-related cognitive deficits. The purpose of this study was to explore the cortical activity using two different measures such as hemodynamic response (fNIRS) and cortical oscillations (EEG) while patients performed a gambling task (IGT) which is a typical decisional risky task that includes uncertainty and reward conditions. 45 PD patients divided into 3 groups were recruited: the first composed by 15 PD patients with Pathological Gambling (PG), the second by 15 PD patients in remission of PG, and the last by 15 PD patients without ICDs. All the participants were administered a neuropsychological battery to test their cognitive state and some self-report questionnaires were used to evaluate the depression and anxiety state (BDI-II, STAI-Y), the impulsivity (BIS) and the motivational style (BIS/BAS scale). Then they were instructed to the IGT while the cortical activity was co-recorded by fNIRS and EEG, focusing on Orbitofrontal (OFC) and Dorsolateral Prefrontal (DLPFC) areas. After the task execution a metacognitive questionnaire was given to test the general self- knowledge of the cognitive strategy adopted during the IGT. Neuropsychological data showed global normal cognitive functions for all the groups, but a significant impairment in hemodynamic and EEG activity in response to more risky conditions mainly for PG, within the PFC. Moreover, this brain dysfunctional activity was related to poorer metacognition and IGT performance.