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Objective To investigate the alteration and possible compensation mechanism of the default mode network (DMN) in patients with subacute pontine infarction.Methods Rs-fMRI data were collected from 23 patients with subacute pontine infarction and 23 normal controls.The data was analyzed with the functional connectivity (FC) method and compared between subacute pontine infarction patients and controls.All imaging was performed on a Philips Achieva 3.0T MRI scanner.Posterior cingulated cortox (PCC) was used as seed points to analyze the FC changes in the brain regions between the pontine infarction group and the controls.The discrepancies of experiment data between two groups were compared by using two-sample t-test analysis.Results The FC of the DMN showed a significant increase in the right postcentral gyrus, left medial prefrontal cortex and left precuneus compared with normal controls and a significant decrease in bilateral insula,posterior lobe of the left cerebellum,right parahippocampal gyrus and left inferior occipital gyrus.Conclusion The DMN altered in patients with subacute pontine infarction and the changes of the FC suggested the plasticity of cortical or compensation in the relevant brain areas.
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Purpose To explore the significance of MR diffusion tensor imaging (DTI) in diagnosing and predicting the motor function of patients with acute ischemic stroke in the brainstem. Materials and Methods Twenty patients with acute ischemic stroke in the brainstem and 20 normal controls were enrolled in the study. DTI was performed on all 40 subjects. Fractional anisotropy (FA) in specific regions were measured including infarction lesions, cerebral peduncle, the posterior limb of the internal capsule in the affected side and corresponding unaffected regions. The number and the length of the corticospinal tracts (CST) of both affected and unaffected sides were also measured. The correlation of FA, the number and the length of the CST, the NIH stroke scale (NIHSS) at the admission, 3 months and 6 months was analyzed. Results The FA values of infarction, cerebral peduncle, and the posterior limb of the internal capsule, and the number of CST in the affected side were significantly less than that of the corresponding unaffected regions (P<0.05). The rFA (<7 d) in the affected cerebral peduncle was negatively correlated with NIHSS and the score of the upper and lower extremity muscle strength at the admission, after 3 months and after 6 months (P<0.05). However, the rFA of the infarction and the posterior limb of the internal capsule, the ratio of the number and the length of CST of affected/unaffected sides had no correlation with NIHSS score and the score of the muscle strength. Conclusion The rFA in the cerebral peduncle is helpful for early evaluation and predicting recovery of the motor function in the patients with acute ischemic stroke in the brainstem.
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Objective To investigate the electrophysiological changes of peripheral nerves in both patients with hereditary neuropathy with liability to pressure palsies(HNPP).Methods The nerve conduction velocities of a family consisting of a proband and 4 members were tested,and the proband was detected by biopsy.Results The proband's median nerve,ulnar nerve,sural sensory nerve conduction velocity (SCV) were decreased.The median nerve,ulnar nerve,common peroneal nerve motor nerve conduction velocity(MCV) of proband were decreased.The sensory fibers of the most frequently involved nerve sural nerve,sural nerve damage to the results:the motor nerve conduction motor nerve evoked potential latency and 18 abnormal rate was 75.0％,the nerve distal to the abnormal rate of MCV was 87.5％.Conclusion Prolongation of distal nerve conduction latencies occurs in essentially all individuals whether symptomatic or asymptomatic.Nerves may be more easily damaged at the site of compression.
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Objective To investigate the characteristics of resting-state functional magnetic resonance imaging (fMRI)in patients post-stroke depression (PSD).Methods Resting-state fMRI scans were performed in 13 patients with and without post-stroke depression.A regional homogeneity (ReHo) approach was used as an indicator.The brain function was analyzed in patients with post-stroke depression.Results Compared to a control group,the ReHo values decreased significantly in a PSD group in the left middle frontal gyrus,right superior frontal gyrus,right middle frontal gyrus,right anterior cingulate gyrus,right posterior cingutate gyrus,left insular lobe,left caudate nucleus,and left hippocampus.Conclusions The patients with PSD had restingstate neural circuit dysfunction,suggesting that the need to focus on the emotional state of stroke patients in the clinical treatment process.
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Objective To investigate any changes in motor functional connectivity in the brains of acute ischemic stroke patients after low frequency electrical stimulation.Methods Twenty-five ischemic stroke patients were given low frequency electrical stimulation in addition to their conventional rehabilitation treatment.Another 20 patients received only conventional treatment as a control group.Resting-state functional magnetic resonance imaging (rs-fMRl)was employed to assess motor function connectivity in the brains of all 45 subjects before and after treatment.Any differences in functional impairment,extremity motor function or ability in the activities of daily living were also recorded before and after treatment.Results In both groups,average scores on the Canadian neurological scale (CNS)and the National Institutes of Health stroke scale (NIHSS) had been reduced significantly after treatment and FuglMeyer assessment (FMA) and modified Barthel index (MBI) scores had significantly increased.The average improvements in terms of FMA and MBI scores were significantly greater in the observation group.Compared with before treatment,the coefficient of functional connectivity of the bilateral motor cortex had decreased significantly after treatment in both groups.In the observation group the changes were significantly correlated with the improvements in FMA scores.Conclusion Neural functional impairment after ischemic stroke can be reduced significantly and extremity motor function and ability in the activities of daily living can be significantly improved by low frequency electrical stimulation.
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ObjectiveTo investigate the brain function in the patients with transient ischemic attack (TIA) using index of regional homogeneity ( ReHo ).MethodsSixteen TIA patients ( TIA group ) and 16 age-matched normal controls(control group) underwent standard resting state functional MRI (fMRI)scan.The changes of the brain ReHo were studied by DPARSF analysis.ResultsCompared with that of control group,TIA group showed significantly decreased ReHo in the left cingulate gyrus (z =-3.72),left frontal gyrus (z =-3.02),right frontal gyrus (z =-3.23),right superior frontal gyrus (z =-3.75),right precuneus (z =-3.80),right inferior parietal lobule (z =-3.98 ),left inferior parietal lobule (z =-3.82),precentral gyrus ( z =- 3.85 ),right midfrontal gyrus ( z =-4.15 ),right midtemporal gyrus (z =- 3.43 ),and increased ReHo in the right hippocampus (z =3.37) and right cerebellum (z =3.55).Conclusion The rest-state brain function is abnormal in TIA interictal phase,and the increased ReHo in the hippocampus and cerebellum may reflect stress-induced brain protection of TIA and partial comoensatory response.
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ObjectiveTo detect the fiber structure and volume differences in frontal lobe between patients with amnestic mild cognitive impairment (aMCI) and normal control.MethodsT1 -weighted magnetic resonance imaging and diffusion tensor imaging were obtained in 28 aMCI patients and 25 normal controls.Volumes,fiber fractional anisotropy (FA),fiber apparent diffusion coefficient (ADC),fiber number,and average fiber length of frontal lobe in the two groups were measured.ResultsVolumes of left frontal lobe ( ( 337.35 ± 20.45 ) cm3 ) in aMCI group were smaller than control ( (358.54 ± 27.26) cm3 ) ( t =- 3.223,P =0.002 ).Numbers of short range fiber in left frontal lobe ( 16985 ± 892) were significantly increased relative to control ( 16387 ±752) ; while numbers of long range fiber (3214 ± 185 ) were reduced compared with control (3425 ± 277 ),and ADC values increased ( t =2.621,P =0.012; t =-3.714,P =0.001 ; t =17.595,P=0.000).In aM CI group,numbers of long range fiber in right frontal lobe were reduced (2895 ± 343 vs.3451 -± 230,t =- 7.011,P =0.000),and ADC values were increased ( t =4.443,P =0.000).In aMCI group,numbers of long range fiber in left frontal lobe were positively correlated with scores of mini-mental state examination ( MMSE ) ( r =0.457,P =0.015 ),while ADC values of long range fiber in left frontal lobe were negatively correlated with scores of MMSE ( r=-0.415,P=0.028).ConclusionThe structure and fiber connectivity are affected in aMCI patients and the lesion of connectivity in left frontal lobe are related to the severity of symptom.