CONECTOME COMPARISON IN MILD COGNITIVE IMPAIRMENT: AD CONTINUUM X SNAP

Abstract

Background: Studies on functional magnetic resonance imaging of prodromal Alzheimer´s disease can help understanding on how it affects the brain. Objective: We seek for potential differences in brain resting state functional connectivity (FC) of subjects with Mild cognitive impairment with biomarkers: Alzheimer’s disease continuum (MCI-DA) and Suspected non-Alzheimer pathology (MCI-SNAP). Methods: MCI and controls were defined by the Clinical Dementia Rating, neuropsychological measures and cerebrospinal fluid data, resulting in 32 MCI-DA, 25 MCI-SNAP and 35 controls. An analysis ROI-to-ROI was performed inter and intra-networks involving the default mode (DMN), salience (SN), visuospatial (VN) and executive networks. FC was estimated by Pearson’s correlation coefficients converted into Z-Scores. Groups were compared by T tests. Alpha was set to 0.05, FDR correction. Results: Between MCI-DA and controls, intra-network decrease of FC in the SN and inter-network between SN and VN was observed. There was maintenance of the anti-correlation between DMN and VN, which may indicate an indirect dysfunction of the DMN. Between MCI-SNAP and controls, there was an increase in FC between one ROI of DMN and one ROI of VN. Conclusion: MCI-AD showed marked differences in FC compared to MCI-SNAP, mainly in salience network and indirectly in DMN. MCI-SNAP showed milder impairment in resting state networks.