Neuroanatomical correlates of the post-stroke aphasias studied with cerebral blood flow SPECT scanning

Researchers are not in complete agreement over the extent to which specific language functions are subserved by certain brain areas. The purpose of this article was to determine neuroanatomical correlates of aphasia following cerebrovascular accident.

The participants included 50 stroke patients with a single left-hemisphere lesion and residual mild to severe aphasia. Language, assessed by the Boston Diagnostic Aphasia Examination (BDAE), was affected to various degrees by a wide range of pathologies. Single-photon emission computed tomography (SPECT) images of the brain were acquired with 740 MBq (20 mCi) of Tc-99m-labeled ECD on a triple-headed gamma camera equipped with low-energy, high-resolution collimator. Correlation between reduced cerebral perfusion and the BDAE score was analyzed.

The most prominent perfusion abnormalities in Broca's aphasia, as determined by the laterality index, were found in the frontal lobe, and to a lesser degree, the parietal lobe and striatum, whereas the most prominent deficits in Wernicke's aphasia were found in the left temporal and parietal areas. In global aphasia, SPECT images evidenced the most extensive damage throughout the perisylvian region of the left hemisphere.

There is need for reinterpretation of the anatomical correlation of selected aphasic syndromes, especially classic Broca's and Wernicke's aphasias. The present study highlights the integrative role of some subcortical structures in language and speech functions. The results support the usefulness of regional cerebral blood flow SPECT imaging as a diagnostic aid in the post-stroke aphasias.