Neuroscience 2002 Abstract
| Presentation Number: | 228.4 |
|---|---|
| Abstract Title: | Structural and functional MRI correlates of cognitive impairment in subjects at risk for Alzheimer's disease. |
| Authors: |
Dickerson, B. C.*1
; Atiya, M.2
; Killiany, R. J.4
; Greve, D.3
; Dale, A. M.3
; Albert, M. S.1,2
; Sperling, R. A.1
1Depts Neurology, Mass General Hospital & Harvard Med School, Boston, MA 2Psychiatry, Mass General Hospital & Harvard Med School, Boston, MA 3Radiology, Mass General Hospital & Harvard Med School, Boston, MA 4Dept Anat, BUMC, Boston, MA |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Neurodegenerative Disorders -- Alzheimers Disease: Cognative function |
| Session: |
228. Neurodegenerative disorders: Alzheimer's disease--imaging studies Slide |
| Presentation Time: | Monday, November 4, 2002 8:45 AM-9:00 AM |
| Location: | Room 315A |
| Keywords: | hippocampus, parahippocampal gyrus, memory |
AD selectively affects mesial temporal lobe regions early in its course. Structural MRI (sMRI) studies have shown that atrophy of the hippocampus (HF) and rostral parahippocampal gyrus (PHG) predicts progression to AD in subjects at risk. In healthy subjects, functional MRI (fMRI) memory tasks activate these regions; it is not yet clear how atrophy and fMRI activation are related in individuals at risk for AD.
We studied 22 older participants in a longitudinal study of cognition who had a range of impairment on the Clinical Dementia Rating Sum-of-Boxes score (CDR-SB=0.0-4.5). Subjects underwent 1) sMRI scans on which HF and PHG regions of interest (ROIs) were manually drawn; 2) an fMRI block-design picture-encoding paradigm known to activate these regions. The number of fMRI voxels in each ROI with task-related activity was calculated.
As expected, worse cognitive impairment was associated with smaller mesial temporal volumes (significant correlations: CDR-SB & RHF, r = -0.49, p<.03; CDR-SB & LPHG, r = -0.44, p<.05). After controlling for volume, however, worse cognitive impairment was associated with a larger number of activated fMRI voxels in the RPHG (r=0.53, p<.01).
These findings suggest that, while subjects with worse cognitive impairment have smaller mesial temporal lobe structures, they recruit a larger extent of the right PHG when encoding new visual information. Follow-up data will reveal whether these non-invasive markers of brain structure and function are useful in predicting if individuals eventually will develop AD.
We studied 22 older participants in a longitudinal study of cognition who had a range of impairment on the Clinical Dementia Rating Sum-of-Boxes score (CDR-SB=0.0-4.5). Subjects underwent 1) sMRI scans on which HF and PHG regions of interest (ROIs) were manually drawn; 2) an fMRI block-design picture-encoding paradigm known to activate these regions. The number of fMRI voxels in each ROI with task-related activity was calculated.
As expected, worse cognitive impairment was associated with smaller mesial temporal volumes (significant correlations: CDR-SB & RHF, r = -0.49, p<.03; CDR-SB & LPHG, r = -0.44, p<.05). After controlling for volume, however, worse cognitive impairment was associated with a larger number of activated fMRI voxels in the RPHG (r=0.53, p<.01).
These findings suggest that, while subjects with worse cognitive impairment have smaller mesial temporal lobe structures, they recruit a larger extent of the right PHG when encoding new visual information. Follow-up data will reveal whether these non-invasive markers of brain structure and function are useful in predicting if individuals eventually will develop AD.
Supported by P01-AG04953 & K23-NS02189
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
Copyright © 2002-2025 Society for Neuroscience; all rights reserved. Permission to republish any abstract or part of any abstract in any form must be obtained in writing by SfN office prior to publication.
