Abstract Details

Title Functional but Not Structural Connectivity Alteration in Mild Alzheimer's Disease: A Preliminary Analyses

Topic Aging and Dementia

Presentation(s) P06 - (-)

Poster/Presentation
Number 042

Objective

Background BACKGROUND: Alzheimer's disease (AD) is the leading cause of dementia in the aging population. Recent research in neuroimaging has revealed dysfunction not only in anatomical areas but also in functional networks in AD patients. The most commonly studied network in AD is the Default Mode Network (DMN), active mainly during cognitive steady states.

Design/Methods DESIGN/METHODS: Images were acquired at 3.0 Tesla from 28 patients with mild AD and 28 healthy control subjects, matched for age and gender. For functional analysis, we used a seed-based approach in posterior cingulate cortex (PCC) to find DMN. FSL and AFNI softwares were used in the preprocessing phase. We performed a t test between groups and results were correct for multiple comparisons by FSL's Randomise. We defined the cingulum bundle as the white matter tract connecting DMN areas - PCC and medial prefrontal cortex (MPC). FSL was used to obtain fractional anisotropy (FA) values. Tract-based spatial statistics (TBSS) was used to compare FA among the two groups.

Results RESULTS: Mild AD patients showed functional disconnection in DMN in PCC, precuneus and MPC compared to controls (p<0.05, FDR corrected). However, there was no significant microstructural alteration in these areas in the same patients regarding FA values.

Conclusions CONCLUSIONS: Mild AD patients do present functional connectivity alterations in resting network, but do not present microstructural alterations. These findings suggest that functional activity in the DMN may act as an early marker for AD pathology. The combination of DTI and fMRI broadens our understanding of human brain connectivity and its pathological changes with AD.

Authors/Disclosures
PRESENTER	No disclosure on file
Clarissa L. Yasuda, MD, PhD (University of Campinas)	Prof. Yasuda has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for LIBBS. Prof. Yasuda has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ABBOTT. Prof. Yasuda has received personal compensation in the range of $0-$499 for serving on a Speakers Bureau for LIBBS.
	No disclosure on file
Fernando Cendes, MD, PhD, FAAN (Departamento de Neurologia; FCM; UNICAMP)	Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB Pharma. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for UCB Biopharma. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for United Medical – Brazil. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Zodiac Pharma . Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Eurofarma – Brazil . Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Epilepsia. Dr. Cendes has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Frontiers in Neurology - Epilepsy. The institution of Dr. Cendes has received research support from São Paulo Research Foundation - FAPESP. The institution of Dr. Cendes has received research support from Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brazil . The institution of Dr. Cendes has received research support from NIH.
Benito P. Damasceno, MD, PhD (Neurology Department, Medical School, State University of Campinas (UNICAMP))	No disclosure on file
Marcio L. Balthazar, MD, PhD (Unicamp)	No disclosure on file
Bernard M. Uitdehaag, MD, PhD, FAAN (Amsterdam University Medical Centers)	Dr. Uitdehaag has nothing to disclose.

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