Resting‐State Functional Connectivity in Frontostriatal and Posterior Cortical Subtypes in Parkinson's Disease‐Mild Cognitive Impairment

Abstract Background The “dual syndrome hypothesis” distinguished two subtypes in mild cognitive impairment (MCI) in Parkinson's disease: frontostriatal, characterized by attentional and executive deficits; and posterior cortical, characterized by visuospatial, memory, and language deficits. Objective The aim was to identify resting‐state functional modifications associated with these subtypes. Methods Ninety‐five nondemented patients categorized as having normal cognition (n = 31), frontostriatal (n = 14), posterior cortical (n = 20), or mixed (n = 30) cognitive subtype had a 3 T resting‐state functional magnetic resonance imaging scan. Twenty‐four age‐matched healthy controls (HCs) were also included. A group‐level independent component analysis was performed to identify resting‐state networks, and the selected components were subdivided into 564 cortical regions in addition to 26 basal ganglia regions. Global intra‐ and inter‐network connectivity along with global and local efficiencies was compared between groups. The network‐based statistics approach was used to identify connections significantly different between groups. Results Patients with posterior cortical deficits had increased intra‐network functional connectivity (FC) within the basal ganglia network compared with patients with frontostriatal deficits. Patients with frontostriatal deficits had reduced inter‐network FC between several networks, including the visual, default‐mode, sensorimotor, salience, dorsal attentional, basal ganglia, and frontoparietal networks, compared with HCs, patients with normal cognition, and patients with a posterior cortical subtype. Similar results were also found between patients with a mixed subtype and HCs. Conclusion MCI subtypes are associated with specific changes in resting‐state FC. Longitudinal studies are needed to determine the predictive potential of these markers regarding the risk of developing dementia. © 2021 International Parkinson and Movement Disorder Society