Temporoparietal cortex in aphasia. Evidence from positron emission tomography
E. J. Metter, W. R. Hanson, C. A. Jackson, D. Kempler, D. van Lancker, J. C. Mazziotta and M. E. Phelps
Gerontology Research Center, National Institute of Aging, Baltimore, MD 21224.
Forty-four aphasic patients were examined with (F18)-fluorodeoxyglucose
positron emission tomography in a resting state to determine whether
consistent glucose metabolic abnormalities were present. Ninety-seven
percent of subjects showed metabolic abnormalities in the angular gyrus,
89% in the supramarginal gyrus, and 87% in the lateral and transverse
superior temporal gyrus. Pearson product moment correlations were
calculated between regional metabolic measures and performance on the
Western Aphasia Battery. No significant correlations were found between the
Western Aphasia Battery scores and right hemisphere metabolic measures.
Most left hemisphere regions correlated with more than one score from the
Western Aphasia Battery. Temporal but not frontal regions had significant
correlations to the comprehension score. The left temporoparietal region
was consistently affected in these subjects, suggesting that common
features in the aphasias were caused by left temporoparietal dysfunction,
while behavioral differences resulted from (1) the extent of
temporoparietal changes, and (2) dysfunction elsewhere in the brain,
particularly the left frontal and subcortical areas.
