Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz

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Gewählte Publikation:

Akguen, O.
Resting state functional brain connectivity in patients with Alzheimer´s Disease in relation to healthy controls and disease severity
[ Diplomarbeit ] Medical University of Graz; 2013. pp. 95 [OPEN ACCESS]


Autor*innen der Med Uni Graz:
Enzinger Christian
Koini Marisa

Objectives: Alterations in default mode network (DMN) activity of the brain have been observed in several neuropsychiatric CNS disorders, in particular in patients with Alzheimer¿s Disease (AD) and even in patients with mild cognitive impairment (MCI). The DMN is usually considered to consist of the posterior and anterior cingulate cortex (PCC and ACC), and structures in parietal and temporal lobes. We here performed functional connectivity (FC) analyses from PCC and ACC (as main constituents of the DMN) to other brain regions using resting-state-fMRI (RS- fMRI) data to test for a correlation between RS-pattern and disease severity. Methods: 12 patients with more severe AD (sAD; MMSE: 15,7 ± 1 SD), 11 patients with milder AD (mAD; MMSE: 24,2 ± 3) and 23 age matched healthy controls (HC) underwent neuropsychological screening with MMSE and RS-fMRI at 3.0T. fMRI-data were preprocessed using SPM5. BOLD-signal fluctuations at 0.009-0.08 Hz within the seed-regions were correlated with whole-brain voxels using REST1.3 to identify regions with significantly correlating signal change. T-tests served to determine FC differences between groups. Multiple regression analyses were used for examining correlations between MMSE-score and connectivity patterns. Results: Both the sAD- and mAD-group showed FC patterns different from HC. Patients with sAD showed more profound alterations and differed from the mAD group. sAD-patients had decreased FC, including but not limited to, between PCC and the medial prefrontal cortex (mPFC). Increased FC was observed in sAD patients deriving from ACC to prefrontal regions. No such results were observed in patients with mAD. Alterations in FC correlated with increasing disease severity (assessed by MMSE) in the patients. Conclusion: Using a relatively novel seed-based voxel-wise FC-analysis, we here confirm previously suggested alterations of FC in AD. Deviations of FC also increased with increasing clinical severity of the disease. Longitudinal studies should test whether these network changes at rest bear predictive value on the disease course.

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