Language-related brain function during word repetition in post-stroke aphasics

Abstract

We compared fMRI findings (using SPM99) obtained with repetition task in normal subjects with those of two patients with Broca's and Wernicke's aphasia who received speech therapy and showed complete recovery. Both aphasic patients with left hemisphere damage who showed complete recovery exhibited activation of only the compensatory area in the right hemisphere during the repetition task. Recovery from Broca's aphasia involves reorganization and neuromodulation between the external temporopolar area and the anterior superior temporal area of the superior temporal gyrus, putamen and the inferior frontal gyrus, while that from Wernicke's aphasia involves reorganization and neuromodulation between the superior temporal gyrus of the temporal region, the posterior supramarginal gyrus and inferior parietal lobule of the parietal region.

Early Aphasia Rehabilitation Is Associated With Functional Reactivation of the Left Inferior Frontal Gyrus

“…Most studies focused on the spontaneous recovery of language, [1][2][3][4][5][6][7] but only a few, often single case descriptions, focused on patients submitted to language rehabilitation. [8][9][10][11][12][13] All of these were conducted on chronic patients.…”

Verbal language spontaneous recovery after ischemic stroke

“…The aphasias are sorted in expressive, with lesion on the cortical and / or subcortical frontal region and emission deficit higher than comprehension (Broca, conduction and transcortical motor); receptive, with lesion on the cortical and / or subcortical temporoparietal region and the comprehension deficit is higher than the emission (Wernicke, transcortical sensorial and anomic); and a mix between expression and comprehension being compromised (mixed transcortical, and global) 7,8 . A re-search showed that the Broca aphasia recovery involves the reorganization between the superior temporal gyrus, putamen and lower inferior temporal gyrus, while Wernicke aphasia involves the reorganization of temporal gyrus, supramarginal gyrus and lower parietal lobe 9 . Aphasic patients who suffered lesion in the brain' s language zones present a certain level of spontaneous recovery in almost all cases, due to neuronal plasticity, defined as any changes on cortical regions such as a the functional or morphological answer to environmental alterations or lesions' 10,11 .…”

Functional MRI-Based Strategy of Therapeutic rTMS Application: A Novel Approach forPost-Stroke Aphasic Patients

“…For example, in the PET study by Ohyama et al (1996), language functional recovery correlated significantly with the activation of the right hemisphere in non-fluent aphasic post-stroke patients. Using functional MRI with language tasks, Abo et al (2004) showed that complete recovery of aphasic symptoms was associated with significant activation of the right hemisphere. Furthermore, Richter et al (2008) identified a stronger neural activation in the right hemisphere on functional MRI during language tasks in aphasic patients compared to normal subjects.…”

“…All functional MRIs were obtained with an EPI gradient echo sequence (parameters for functional MRI: 6 mm slice thickness, field of view 240 mm, TR 5000 ms, TE 90.5 ms, 80 degree flip angle, and matrix 128×128 and oriented identical to the anatomical images). With regard to the repetition task, patients were asked to repeat aloud a series of www.intechopen.com words (common nouns frequently used in daily usual conversation) that were delivered every three seconds through earphones, after confirmation that the patient was able to repeat correctly more than half of the words of the tasks (Abo et al, 2004). Axial and coronal images of conventional T1-weighted scans were also taken to anatomically coregister with images of functional MRI and accurately localize the activated areas (parameters for T1-weighted images: 2 mm slice thickness, field of view 240 mm, TR 26 ms, TE 2.4 ms, and matrix 256×256).…”