Frontal lobe Anatomical differences in Parkinson's disease patients based on impulse control disorder features

Impulse control disorder (ICD) is a complex, and often debilitating, symptom of Parkinson Disease (PD). The frontal lobes have been associated with complex decision making and are implicated as part of the impulse control pathway. We predicted patients with PD (PwPD)with ICD would have atrophy in frontal lobe regions compared to patients with nonICD. We aimed to identify the presence of frontal lobe alterations in PwPD based on ICD behavior using structural neuroimaging methodology. This study expands the current literature regarding cortical anatomy in patients with PDICD and focuses on future investigations. This retrospective study utilized data from two centers including PwPD with ICD (PDICD, n = 32) and without ICD (PDnonICD, n = 41). Participants were grouped based on responses to the MDS-UPDRS part I.6 question, and the questionnaire for impulsive-compulsive disorder in PD. Healthy control (HC) data (n = 42) was obtained from the Parkinson Progression Marker Initiative project. T1-weighted 1 mm³ 3 T MRI images were obtained and CAT12 software was used for automated segmentation, and generation of cortical thickness and volume of regions of interest.Multivariate analysis of covariance was used to compare differences between groups. The PDICD group demonstrated significantly smaller Superior Frontal Gyri (SFG) volume compared to the PDnonICD and HC groups (p = 0.034 and 0.004 respectively). Orbitofrontal gyri thickness showed significant reduction in PDICD and PDnonICD compared to HC (p < 0.001 and < 0.004 respectively). While SFG volume was reduced in PDICD compared to PDnonICD is suggestive of unique brain changes in PDICD that further characterize this subset of patients and may be related to their symptomatology.