title: Resting-state functional connectivity associated with mild cognitive impairment in Parkinson's disease.
abstract: Cognitive impairment is common in PD, even in early stages. The construct of mild cognitive impairment has been used to identify clinically evident cognitive impairment without functional decline in PD patients (PD-MCI). The aim of the present study was to investigate brain connectivity associated with PD-MCI through RS-fMRI. RS-fMRI at 3T was collected in 42 PD patients and 20 matched healthy controls. Among PD patients, 21 were classified as having MCI (PD-MCI) and 21 as cognitively unimpaired (PD-nMCI) based on criteria for possible PD-MCI (level I category). Single-subject and group-level ICA was used to investigate the integrity of brain networks related to cognition in PD patients with and without MCI. Image data processing and statistical analysis were performed in BrainVoyager QX. In addition, we used VBM to test whether functional connectivity differences were related to structural abnormalities. PD-nMCI and PD-MCI patients compared with controls showed decreased DMN connectivity. PD-MCI patients, but not PD-nMCI, compared with controls, showed decreased functional connectivity of bilateral prefrontal cortex within the frontoparietal network. The decreased prefrontal cortex connectivity correlated with cognitive parameters but not with clinical variables. VBM analysis did not reveal any difference in local gray matter between patients and controls. Our findings suggest that an altered DMN connectivity characterizes PD patients, regardless of cognitive status, whereas a functional disconnection of the frontoparietal network could be associated with MCI in PD in the absence of detectable structural changes.
authors.affiliation: Neurodegenerative Diseases Center, Department of Medicine and Surgery, University of Salerno, Via Allende, 84081, Baronissi, SA, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Amboni
authors.forename: Alessandro
authors.initials: A
authors.lastname: Tessitore
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Esposito
authors.forename: Gabriella
authors.initials: G
authors.lastname: Santangelo
authors.forename: Marina
authors.initials: M
authors.lastname: Picillo
authors.forename: Carmine
authors.initials: C
authors.lastname: Vitale
authors.forename: Alfonso
authors.initials: A
authors.lastname: Giordano
authors.forename: Roberto
authors.initials: R
authors.lastname: Erro
authors.forename: Rosa
authors.initials: R
authors.lastname: de Micco
authors.forename: Daniele
authors.initials: D
authors.lastname: Corbo
authors.forename: Gioacchino
authors.initials: G
authors.lastname: Tedeschi
authors.forename: Paolo
authors.initials: P
authors.lastname: Barone
mesh_terms: D000368:Aged; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology*; D012146:Rest