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P2‐018: Deactivation of precuneus is reduced during naming in early dementia
Author(s) -
Hüll Michael H.,
Abel Stefanie,
Dressel Katharina,
Saur Dorothee,
Kümmerer Dorothee,
Mast Hansjörg,
Weiller Cornelius,
Frings Lars
Publication year - 2008
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2008.05.1098
Subject(s) - precuneus , default mode network , audiology , frontotemporal dementia , dementia , psychology , atrophy , cognition , posterior cingulate , neuroscience , medicine , disease
dissociations between medial temporal volume loss and metabolic reductions in posterior association cortices in AD patients. The present study investigates lobar gray and white matter volume loss in AD using data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. Methods: 1.5 Tesla MR brain images from 18 subjects with AD and 18 ageand sex-matched subjects with normal cognition (NC) were obtained from the ADNI public database (www.loni.ucla.edu ADNI). T1-weighted, 3-D volumetric MP-RAGE images were analyzed in a multi-step process. Brain parenchyma was segmented into gray matter and white matter using an automated program. Lobar gray and white matter volumes in frontal, temporal, parietal and occipital lobes were delineated using a landmarkbased, manual method and normalized to total intracranial volume. Between-group differences in lobar gray and white matter volumes were compared using student’s t-test. Results: AD subjects (mean age 75, mean MMSE 23.4, all CDR 1) demonstrated significantly reduced gray matter volumes vs. NC (mean age 75, mean MMSE 29.1, all CDR 0) in frontal (10.39 vs. 11.60, p 0.01), temporal (6.91 vs. 8.44, p 0.01) and parietal (6.14 vs.7.10, p 0.01) lobes. There was no difference between groups in occipital gray matter volume (3.46 vs. 3.60, p 0.30). White matter volume in the parietal lobe was significantly decreased in AD vs. NC (10.09 vs. 10.94, p 0.05). Conclusions: This analysis from the ADNI public database reveals AD-associated gray matter volume loss in brain regions serving higher functions (frontal, temporal and parietal lobes), but not in regions serving primary functions (occipital lobe). Furthermore, we observed white matter volume loss in the parietal lobe of AD, a novel finding which has not been previously described. This new finding may represent axonal loss from degenerating neurons in multimodal association cortices, or reduced integrity of fibers in the posterior cingulate bundle connecting medial temporal lobe structures to posterior cingulate gyrus.