Abstract
ObjectiveTo determine if Alzheimer disease (AD) is associated with aphasic rather than amnestic dementias in certain circumstances related in part to perturbations in different networks.MethodsThree groups were investigated: 14 participants suspected of having the neuropathology of AD based on clinically diagnosed amnestic dementia of the Alzheimer type (DAT), 26 individuals with primary progressive aphasia (PPA) with either a positive 18F-florbetapir amyloid PET scan or confirmed AD at autopsy, and 26 neurologically intact controls. The groups were compared using rs-fMRI. Seeds included the left hemisphere inferior frontal gyrus (IFG) for the language network, the left hippocampus for the episodic memory network, and the left posterior cingulate for the default mode network (DMN).ResultsGreater connectivity perturbations were found from the hippocampus for the DAT group and from the IFG for the PPA group. Furthermore, connectivity alterations in the PPA group were more asymmetric and favored the language-dominant left hemisphere. Loss of connectivity from the DMN seed was of a similar magnitude in the PPA and DAT groups.ConclusionsDespite the presumptive common underlying neuropathology of amyloid plaques and neurofibrillary tangles, the 2 groups displayed 2 different patterns of network perturbation, each concordant with the clinical presentation and the anatomy of neurodegeneration.
Original language | English (US) |
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Pages (from-to) | E699-E704 |
Journal | Neurology |
Volume | 94 |
Issue number | 7 |
DOIs | |
State | Published - Feb 18 2020 |
Funding
This project was supported by R01DC008552 from the National Institute on Deafness and Communication Disorders; AG13854 (Alzheimer Disease Core Center), T32AG020506, and R01AG056258 from the National Institute on Aging; and R01NS075075 from the National Institute of Neurologic Disorders and Stroke. This is not an industry-sponsored study.
ASJC Scopus subject areas
- Clinical Neurology