ABSTRACT
Previous researches about the brain mechanism of aphasia mainly focused on the correspondence between cortical brain regions and language function. Now, more and more researches have found that the connection of white matter tracts in the brain plays an important role in language function. Dual-stream language model hypothesizes that the process of language can be considered as two parallel pathways, dorsal and ventral. The white matter fibers of dorsal stream include arcuate fasciculus and superior longitudinal fasciculi, which are mainly involved in the production of language. The white matter fibers of ventral stream include the inferior frontal-occipital fasciculus, inferior longitudinal fasciculus and uncinate fasciculus, which are mainly responsible for language understanding. The conception of connection mode and specific functional role of these fibers in the language network of patients with aphasia is helpful for the assessment of the features and severity of the patient's language dysfunction and outcome, to guide clinical precision rehabilitation. More researches are needed to elaborate the interaction between the dorsal and ventral streams to well know the brain's language network processing mechanism.
ABSTRACT
Objective:To investigate the changes of gray matter volume in patients with chronic nonfluent aphasia after cortical cerebral infarction and the relationship between gray matter volume and language function. Methods:From June, 2016 to June, 2019, 19 patients with chronic nonfluent aphasia after cortical cerebral infarction from the First Affiliated Hospital of Ji'nan University and 28 healthy subjects (controls) were scanned with structural magnetic resonance imaging. The data were analyzed using voxel-based morphological measurement to measure the gray matter volumes of the brain regions, and the differences between patients and controls were compared. The correlation between volumes of brain regions with difference and scores of items of Aphasia Battery of Chinese (ABC) was analyzed. Results:The gray matter volumes increased in the brain regions of right inferior frontal gyrus triangle, right inferior frontal gyrus island cover, right angular gyrus, the right medial frontal gyrus, left insula, left medial frontal gyrus in the patients; while decreased in right globus pallidus. The volumes of left insular lobe correlated with the scores of repeating (r = 0.665, P = 0.001) and naming (r = 0.638, P = 0.003); and the volumes of right inferior frontal gyrus triangle correlated with the scores of hearing comprehension (r = 0.493, P = 0.031), repeating (r = 0.576, P = 0.009) and naming (r = 0.674, P = 0.001) in the patients. Conclusion:The cortex volumes of left insula and right inferior frontal gyrus triangle increase in patients with chronic nonfluent aphasia after cerebral infarction, which may play a role in the language dysfunction.