Preserved repetition in thalamic afasia. A pathophysiological hypothesis / Preservação da repetição na afasia talâmica. Uma hipótese fisiopatológica

ABSTRACT. The ability to repeat words is almost always preserved in thalamic aphasia. The pathophysiology of both thalamic aphasia and preservation of repetition are not fully understood. In a case of severe aphasia with preserved repetition after a left thalamic hemorrhage, MRI disclosed left thalamic lesion and loss of fractional anisotropy in the left centrum semiovale. FDG-PET showed severe hypometabolism in the left cerebral hemisphere, except for superior and transverse temporal gyri, calcarine fissure and frontopolar regions. Primary sensory function may be less functionally dependent on thalamic connections than heteromodal and paralimbic areas, which have connections with several thalamic nuclei. The extensive cortical hypometabolism due to diaschisis may have been responsible for the severity of the aphasia, whereas the less severe reduction of metabolism in the superior and transverse temporal gyri, and also, albeit less evident, in Broca's area, might explain the preservation of repetition.

RESUMO. A capacidade de repetir palavras é quase sempre preservada na afasia talâmica. A fisiopatologia da afasia talâmica assim como a da preservação da repetição não são totalmente compreendidas. Em um caso de afasia grave com repetição preservada após hemorragia talâmica esquerda, a RM revelou lesão talâmica esquerda e perda de anisotropia fracionada no centro semioval. O FDG-PET revelou hipometabolismo grave no hemisfério cerebral esquerdo, exceto nos giros temporais superiores e transversos, fissura calcarina e regiões frontopares. A função sensorial primária pode ser menos funcionalmente dependente das conexões talâmicas do que as áreas heteromodais e paralímbicas, que têm conexões com vários núcleos talâmicos. O hipometabolismo cortical extenso devido à diasquise pode ter sido responsável pela gravidade da afasia, enquanto a redução menos severa do metabolismo nos giros temporal superior e transverso, e também, embora menos evidente, na área de Broca, poderia explicar a preservação da repetição.

Mechanism of Subcortical Aphasia: A Diffusion Tensor Imaging Study / 中国康复理论与实践

@#Objective To explore the connection of fibers among functional language areas in the normals and the patients with subcortical aphasia using diffusion tensor imaging (DTI) and diffusion tensor fiber tractography (DT-FT). Methods From June, 2016 to May, 2017, 20 healthy subjects and three stroke patients whose lesion located in subcortical structures were included. There were two patients with Broca's aphasia and one with conductive aphasia from the Western Aphasia Battery. They were scanned with DTI and DT-FT, while the fractional anisotropy (FA) of functional language areas and contralateral mirror areas were measured, and the relevant fibers were observed. Results The structures of functional language areas were complicated and extensively connected with other cortex and subcortical structures in healthy subjects, with few differences among individuals. FA was lower in the functional language areas and arcuate fasciculus than in the mirror regions in patients, and the fibers were damaged, distorted or shifted.Conclusion Structures related to language are very complicated, which involve cortex, lots of white matter tracts, subcortical structure and others. The damage, transformation or transposition of fibers in functional language areas may be the mechanism of subcortical aphasia.

Features and Pathogenesis of Subcortical Aphasia (review) / 中国康复理论与实践

@# With the development of imaging techniques, aphasia caused by subcortical impairment is increasingly found in recent years. This paper reviewed the literature about the subcortical aphasia and expolred the anatomical and clinical features and pathogenesis of subcortical aphasia.

Features and Pathogenesis of Subcortical Aphasia (review) / 中国康复理论与实践

With the development of imaging techniques, aphasia caused by subcortical impairment is increasingly found in recent years. This paper reviewed the literature about the subcortical aphasia and expolred the anatomical and clinical features and pathogenesis of subcortical aphasia.

Features and Pathogenesis of Subcortical Aphasia (review) / 中国康复理论与实践

@# With the development of imaging techniques, aphasia caused by subcortical impairment is increasingly found in recent years. This paper reviewed the literature about the subcortical aphasia and expolred the anatomical and clinical features and pathogenesis of subcortical aphasia.

Statistical Mapping Analysis of Brain Metabolism in Patients with Subcortical Aphasia after Intracerebral Hemorrhage: A Pilot Study of F-18 FDG PET Images

PURPOSE: This study was aimed to evaluate the brain metabolism in patients with subcortical aphasia after intracerebral hemorrhage (ICH) and the relationship between the severity of aphasia and regional brain metabolism, by using statistical mapping analysis of F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) images. MATERIALS AND METHODS: Sixteen right-handed Korean speaking patients with subcortical aphasia following ICH were enrolled. All patients underwent Korean version of the Western Aphasia Battery and the brain F-18 FDG PET study. Using statistical parametric mapping analysis, we compared the brain metabolisms shown on F-18 FDG PET from 16 patients with subcortical aphasia and 16 normal controls. In addition, we investigated the relationship between regional brain metabolism and the severity of aphasia using covariance model. RESULTS: Compared to the normal controls, subcortical aphasia after ICH showed diffuse hypometabolism in the ipsilateral cerebrum (frontal, parietal, temporal, occipital, putamen, thalamus) and in the contralateral cerebellum (P corrected <0.001), and showed diffuse hypermetabolism in the contralateral cerebrum (frontal, parietal, temporal) and in the ipsilateral cerebellum (P FDR corrected <0.001). In the covariance analysis, increase of aphasia quotient was significantly correlated with increased brain metabolism in the both orbitofrontal cortices, the right hippocampal and the right parahippocampal cortices (P uncorrected <0.01). CONCLUSION: Our findings suggest that frontal, parietal, and temporal cortices, which are parts of neural network for cognition, may have a supportive role for language performance in patients with subcortical aphasia after ICH.

Effect of Acupuncture Combined with Language Training on Subcortical Aphasia / 中国康复理论与实践

@#Objective To observe the clinical effect of acupuncture combined with language training on subcortical aphasia.Methods 32 cases in treatment group and 26 cases in control group were given routine medication,in addition,treatment goup accepted acupuncture and language training.Results After 4 weeks of treatment,patients' language function improved significantly in treatment group compared with that of control(P<0.05).The total effective rate was 87.5% in treatment group,while it was 61.5% in control group(P<0.05).Conclusion Acupuncture combined with language training is effective on subcortical aphasia.

The Therapeutic Effect of Inhibitory Repetitive Transcranial Magnetic Stimulation on Right Inferior Frontal Gyrus in Subcortical Aphasia

OBJECTIVE: To investigate whether suppression of right inferior frontal gyrus (Broca's homologue) by 1 Hz repetitive transcranial magnetic stimulation (rTMS) can improve speech recovery. METHOD: We applied low frequency rTMS on right Broca's homologue twice a week for 6 weeks in eight subcortical aphasia patients who were 3 months to 3 years poststroke onset. They were tested with Korean Version-Western Aphasia Battery before and after procedure. Also, they were tested with Parallel Short Forms for the Korean-BostonNaming Test and Animal Naming Test serially for outcome measure. rTMS was performed with intensity of 80% of motor threshold for 10 min (600 pulses) at 1 Hz frequency. RESULTS: Significant improvement was observed in picture naming at post-rTMS only in nonfluent aphasia patients but not in fluent aphasia patients. CONCLUSION: rTMS may provide a novel treatment for aphasia by possibly modulating the distributed, bi-hemispheric language network.

Types, Severity and Prognostic Factors in Subcortical Aphasia

OBJECTIVE: The purpose of this study is to evaluate the types of aphasia and the clinicoanatomic correlation in aphasic patients with subcortical lesions, and to investigate the change in the types of aphasia during the recovery stage. METHOD: Twenty-three stroke patients (16 men and 7 women) with left subcortical lesion was investigated. On the basis of the brain CT or MRI findings, the patients were divided into the 4 groups. Language dysfuntion was evaluated using the modified Western Aphasia Battery (WAB) and the type of aphasia and aphasia quotient were determined. Initial examination was performed within 2 months post-onset in all of the patients and the follow-up examination was done after 6 months post-onset in 9 patients. RESULTS: The most common type was anomic aphasia (39%). The type of subcortical aphasia was variable regardless of the sites of left subcortical lesion. Aphasia quotient was significantly related with the lesion size (gamma = 0.05, p<0.05) and the initial Barthel index (gamma = 0.65, p<0.05). The scores of all the subtests of the modified WAB and aphasia quotient were significantly decreased in the group with the cortical involvement or the history of operation. On the follow-up examination, the scores of fluency, information and naming subtests were significantly increased. CONCLUSION: The most common type of aphasia was anomic aphasia and the type of subcortical aphasia was not correlated to the anatomic lesion. Severity of subcortical aphasia would be related with the lesion size, the history of operation or the cortical involvement. The prognosis of subcortical aphasia was generally good.

Subcortical Aphasia in Stroke Patients

OBJECTIVE: The purposes of this study were to identify the incidence of subcortical aphasia and to investigate the different linguistic characteristics and prognosis. METHOD: Twenty-nine stroke patients(18 men and 11 women) with aphasia were investigated in the study. On the basis of the findings of brain CT and MRI images, the patients were divided into either cortical aphasia group or subcortical aphasia group. Fifteen cortical aphasia patients and 14 subcortical aphasia patients underwent an aphasia screening test. Fluency, comprehension, speech, naming, repetition, reading, and writing abilities were evaluated as the modalities of language. All patients received the speech therapy and were reevaluated at three months after the initial evaluation. RESULTS: The incidence of subcortical aphasia was 48.3% of all aphasia patients from the stroke. Subcortical aphasia patients showed more variable types of aphasia and less linguistic damage than the cortical aphasia patients. The prognosis of subcortical aphasia patients was better than the cortical aphasia patients. Especially the cases of global aphasia from the subcortical lesions showed a rapid recovery and good prognosis. CONCLUSION: Early recognition of the subcortical aphasia and a comprehensive speech therapy would be beneficial for the improvement of linguistic function in the subcortical aphasia patients.