Improvement of Speech Function in Patients with Aphasia: The Right Hemisphere, an Enemy or a Friend?

Аннотация

The purpose of our research is to investigate interhemispheric language functional reorganization in patients with gliomas of the left hemisphere using functional magnetic resonance tomography (fMRI) in comparison with the dynamics of speech disorders. A total of 20 patients with a glioma in the left hemisphere underwent fMRI examination and Luria’s neuropsychological testing. The age of patients varied from 26 to 67 years; the mean age was 40 years (median, interquartile range; 13 women and 7 men). The glioma was located in the frontal lobe (12 patients) 34.50–49.75 years; or in the temporal lobe (8 patients). All patients underwent both fMRI scanning and neuropsychological testing on the same day before the surgery and then 3–10 days and 3, 5–7, 12 months after tumor surgery. The handedness was determined by using self-assessment and the Annett Hand Preference Questionnaire. Almost all the subjects were right-handed, and one was ambidexter. On the basis of the analysis of fMRI data in dynamics, all subjects were divided into two groups: (1) patients with no signs of activation of the right hemisphere homologues of Broca’s and Wernicke’s areas (even in 4 patients with severe aphasia) during the follow-up period (at least one year), and (2) patients with signs of activation in the right-sided Broca’s and Wernicke’s areas, which were found in at least several tests (16 patients; 3 of them had normal speech function during the whole follow-up period). We conclude that the lack of consistency between the presence/absence of aphasia and the activation of homologous speech areas in the right hemisphere in fMRI results from individual differences in the involvement of the right hemisphere in speech processes. Thus, we should be very cautious about the hypothesis of reciprocal relationships of the hemispheres in speech function and the use of this hypothesis in speech rehabilitation.