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Abstract:
Patients with Alzheimer's and Frontotemporal Dementia present
with considerable variation in the relative severity of different
cognitive deficits. This variation in cognition is most likely a
result of variation in the anatomic distribution of pathology.
Study of the relationship between the distribution of pathology and
cognitive deficit could illuminate both the diagnosis of dementia
and the nature of the neural circuits involved. We employed a new
functional imaging technique, arterial spin labeled MRI, to map
absolute cerebral blood flow in a cohort of demented patients.
After the images of each subject were warped to a standard brain
coordinate system, the correlation between performance on five
language intensive tasks and cerebral blood was determined for each
voxel. This procedure produced significant correlations for each of
the five tasks. While the group as a whole demonstrated bilateral
blood flow decreases relative to normal controls, the language task
correlations were all strongly left hemisphere dominant. Individual
task correlations demonstrated differing anatomic distributions,
which may have implications for the neural substrates of semantic
and grammatical processing. Correlation of cognitive test
performance with cerebral blood flow MRI is a promising approach to
the study of cognitive dysfunction in dementia.
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