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Neuroplasticity in language recovery-a longitudinal study with a post stroke aphasic patient
Poster Session D, Saturday, October 26, 10:30 am - 12:00 pm, Great Hall 3 and 4
Qingchun WANG1, Fang WANG2, Yang LIU2, Lu YU2, Yongkun GUO2, Xinjun WANG*2,3, Wai-Ting SIOK*1; 1The Hong Kong Polytechnic University, Hong Kong SAR, China, 2The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China, 3The Third Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
The neuroplasticity of the brain is a key biomarker for language recovery. Previous studies have shown that the anatomical structure of the brain adapts to internal and environmental changes. However, few studies have investigated the dynamic evolution of the brain within the critical period of recovery with multiple examinations. In this study, we present a detailed 6-month longitudinal case report of an aphasic patient who suffered from a unilateral stroke. The patient is a 60 years old, well-educated native speaker of Mandarin, right-handed male with no previous history of neurological diseases or psychiatric disorders. We carefully examined the neuroanatomical features of the brain and documented the patient's linguistic profile from the acute stage to the chronic post-stroke phase. The patient received intensive language therapies during rehabilitation. Language performances were assessed by a comprehensive aphasia battery for multiple times. Neuroimaging data which captured the anatomical and structural features of the brain were collected at three time points with an exact time interval of 2 months. We used Voxel-Based Morphometry (VBM) to detect changes in tissue volume, and diffusion tensor imaging (DTI) data to assess the microstructural integrity of white matter tracts. Ten healthy participants matched for age and educational level served as the control group. A pattern of gradual improvements in all tested linguistic domains was observed during the critical period. Gray matter (GM) analyses from the first MRI examination showed a cluster (k = 303, suprathreshold voxels) in the left hippocampus (voxel peaks: x = -34.5, y = -15, z = -15). The second and third MRI examinations revealed similar patterns. White matter (WM) analyses showed significant reductions in a large cluster (7,800 voxels) predominantly in the left hemisphere (voxel peaks: x = -33, y = -75, z = 1.5) and a smaller cluster (244 voxels) in the right hemisphere (voxel peaks: x = 34.5, y = 7.5, z = 18) during the first MRI examination. These differences were consistent in the second examination. Six months post-stroke, only one cluster (voxel peaks: x = -37.5, y = -63, z = 31.5) of WM in the left hemisphere survived the statistical threshold. The left hemisphere showed the highest WM volume reductions in regions beneath the middle occipital gyrus, inferior temporal gyrus, middle temporal gyrus, fusiform gyrus, angular gyrus, and supramarginal gyrus. The patient exhibited lower fractional anisotropy (FA) values in all target fiber tracts except for the left uncinate fasciculus (UF), indicating reduced structural integrity. Over the observation period, a gradual decrease in FA values was observed in the arcuate fasciculus (AF), superior longitudinal fasciculus I and II (SLF_I, SLF_II), inferior longitudinal fasciculus (ILF), middle longitudinal fasciculus (MdLF), and UF, suggesting fiber atrophy. In conclusion, this study presents a comprehensive examination of the dynamic evolution of the brain within the critical period of language recovery. Our results emphasize the beneficial effects of intensive language therapy. Neuroimaging results suggest that disruptions in structural connectivity are a primary cause of aphasia and that fiber pathway degenerations may limit language recovery.
Topic Areas: Disorders: Acquired,