ABSTRACT
Repeatitive transcranial magnetic stimulation can adjust cortical excitability and improve swallowing function in patients with dysphagia after stroke. High frequency stimulations with 90% to 130% resting motor threshold (rMT) in the early stage, as well as low frequency stimulations with 100% to 130% rMT for 1200 pulse in the recovery period, may be beneficial to the recovery of swallowing function, and bilateral stimulation may be more effective.
ABSTRACT
Objective:To analyze the structure and function of white matter in autistic children by using diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS), to explore the imaging features of abnormal neural connectivity in children with autism. Methods:Autism group (n = 14) and control group (n = 8), aged two to nine years, underwent DTI and MRS scan. Bilateral frontal lobe, hippocampus, genu and splenium of corpus callosum and cerebellum white matter were selected as regions of interest. The data of DTI and MRS were processed by Functool 2.6 software of GEAW4.2 workstation. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of DTI, the absolute concentrations of N-acetylaspartate (NAA), choline (Cho), creatinine (Cr) and the ratios of NAA/Cr and Cho/Cr were recorded respectively. Results:Compared with the control group, the FA of left hippocampus (F = 5.922, P = 0.033) and the absolute concentration of Cr in left and right hippocampus (F > 4.715, P < 0.05) decreased significantly in the autism group. The FA was lower in left corpus callosum genu than in the right one (F = -2.335, P = 0.042), and the ADC was higher in left corpus callosum splenium than in the right one (F = 3.520, P < 0.01) in the autism group. The absolute concentration of NAA, Cho and Cr in left frontal lobe (|t| > 2.648, P < 0.05), the absolute concentration of NAA in left corpus callosum splenium (t = -3.076, P = 0.009) and Cho/Cr in left cerebellum (t = -2.225, P = 0.044) were significantly lower than those in the right cerebral hemisphere in the autism group. The DTI and MRS indexes were not different between left and right hemispheres in the control group (P > 0.05). Conclusion:Abnormal metabolite or functional alternations were found in the frontal lobe, hippocampus, cerebellum and the genu and splenium of the corpus callosum in autistic children, suggesting underconnectivity intra- or inter-hemispheric neural, especially in left hemisphere.