Recognition method of single trial motor imagery electroencephalogram signal based on sparse common spatial pattern and Fisher discriminant analysis / 生物医学工程学杂志

This paper aims to realize the decoding of single trial motor imagery electroencephalogram (EEG) signal by extracting and classifying the optimized features of EEG signal. In the classification and recognition of multi-channel EEG signals, there is often a lack of effective feature selection strategies in the selection of the data of each channel and the dimension of spatial filters. In view of this problem, a method combining sparse idea and greedy search (GS) was proposed to improve the feature extraction of common spatial pattern (CSP). The improved common spatial pattern could effectively overcome the problem of repeated selection of feature patterns in the feature vector space extracted by the traditional method, and make the extracted features have more obvious characteristic differences. Then the extracted features were classified by Fisher linear discriminant analysis (FLDA). The experimental results showed that the classification accuracy obtained by proposed method was 19% higher on average than that of traditional common spatial pattern. And high classification accuracy could be obtained by selecting feature set with small size. The research results obtained in the feature extraction of EEG signals lay the foundation for the realization of motor imagery EEG decoding.

Study on the shift of ocular vestibular evoked myogenic potentials frequency tuning of Meniere′s disease / 中华耳鼻咽喉头颈外科杂志

Objective@#To study the shift of oVEMP frequency tuning of unilateral Meniere′s disease, by analyzing oVEMP of air-conducted tone bursts in various frequencies.@*Methods@#From May 2016 to October 2017, 33 patients with unilateral Meniere′s from Aerospace Center Hospital were tested for oVEMP in 500 Hz and 1 000 Hz air-conducted tone bursts respectively, and 20 healthy subjects(40 ears), matched for age and sex, were used as healthy control. The amplitudes of the N1-P1 wave and the frequency amplitude ratios of 500/1 000 Hz in affected ears, unaffected ears and normal ears were compared; and receiver operating characteristic curve was analyzed for frequency amplitude ratios of 500/1 000 Hz.@*Results@#By the 500 Hz tone-burst stimulus, the provocation rates of the oVEMP were 84.9%(28/33), 93.9%(31/33) and 97.5%(39/40) in affected ears, contralateral ears and the ears of normal controls, respectively. By the stimulus of 1 000 Hz tone-burst, the provocation rates of the oVEMP were 81.8%(27/33), 87.9%(29/33) and 82.5% (33/40) in affected ears, contralateral ears and normal control ears, respectively. Amplitudes of N1-P1 waveforms in 500 Hz air-conducted tone bursts in affected ears were under normal control ears and contralateral ears. There was significant difference between affected ears and healthy control ears (P<0.05). Amplitudes of N1-P1 waveforms in contralateral ears were also significantly smaller than those in normal control ears (P<0.05). There were no significant differences in amplitudes of N1-P1 waveforms between affected ears, contralateral ears and normal control ears in 1 000 Hz tone bursts stimulus(P>0.05). Frequency amplitude ratios of 500/1 000 Hz in affected ears were significantly under contralateral and normal control ears (P<0.05). According to ROC, the frequency amplitude ratio critical value of frequency tuning was set as 1.17, the positive rate of frequency tuning shift in affected ears was 54.5%(18/33) and significantly higher than in contralateral ears(18.2%, 6/33, χ2=9.429, P=0.002) and normal control ears (7.5%, 3/40, χ2=19.530, P=0.000). In contrast, there was no significant difference in the incidence of frequency tuning shift between contralateral ears and normal ears(χ2=1.909, P=0.167).@*Conclusions@#Frequency tuning oVEMP with Meniere′s disease will be changed.Frequency tuning of oVEMP with Meniere′s disease shifts from low frequency region to high frequency region in comparison with healthy people. Frequency amplitude ratio is helpful for diagnosis of Meniere′s disease.

The Feasibility and Effectiveness of the Simultaneous Recording of Ocular and Cervical Vestibular-evoked Myogenic Potentials / 听力学及言语疾病杂志

Objective To study the feasibility of simultaneously recording ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) by combined oVEMP and cVEMP tests.Methods Twenty healthy volunteers and twenty-three patients with Meniere's disease were admitted and underwent combined oVEMP and cVEMP tests in a random order,and individual oVEMP and cVEMP tests on another day.The results of combined and individual oVEMP and cVEMP tests were compared.Results For twenty healthy volunteers in oVEMP and cVEMP tests,the 100％ response rate were observed in the both combined and individual test modes.The differences in amplitudes and latencies and interaural amplitude difference were insignifi-cant.For twenty-three patients with Meniere's disease,the results of oVEMP/cVEMP for the affected and unaffected ears failed to sow any significant differneces,regardless of the individual or combined mode.Conclusion The simultaneous recording of oVEMP and cVEMP by the combined mode has similar results to that obtained by individual mode for both healthy or unilateral vestibular hypofunction.Simultaneous oVEMP and cVEMP tests may be a convenient screening test and deserves further clinical applications.

Three-dimensional reconstruction and visualization of the fronto-ethmoidal cells based on CT images / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#Based on contiguous axial computed tomography (CT) images of the frontal sinus, a three-dimensional (3D) visualization and reconstruction of fronto-ethmoidal cells was performed using Intage Realia (version 2011) software to generate a model to accurately understand the anatomical structure of fronto-ethmoidal cells.@*METHOD@#Retrospective analyses of nose CT scan data of 50 patients without sinusitis were performed. Using Digital Imaging and Communications in Medicine (DICOM) images of sinus axial CT scans, the 3D visualization and reconstruction of the sinus was performed using the Achilles tendon and nasal passage modes in Intage Realia (version 2011) software on personal computers. Two segmentations were performed on the reconstructed sinus, and the structures of the agger nasi, frontal cells, and supraorbital cells and the relative locations of the frontal sinus drainage pathway and cells were observed.@*RESULT@#The 3D visualization of the fronto-ethmoidal cells and frontal sinus drainage pathway was successful, allowing accurate observation of the anatomical characteristics of the fronto-ethmoidal cells.@*CONCLUSION@#The 3D visualization of fronto-ethmoidal cells can be reconstructed based on contiguous axial CT images of the sinus, allowing an accurate understanding of the anatomical structure of fronto-ethmoidal cells and is well prepared for frontal sinus surgeries.

Establishment of an auditory deprived mouse model / 基础医学与临床

Objective To explore a method for establishing stable auditory deprived animal model of mouse.Methods Forty two-month old BALB/c mice with normal auditory brainstem response(ABR) thresholds were divided into two groups randomly.The experimental group underwent an incision inferior to the pinna,and the cochleas were destoried with a drill through the bulla bilaterally.The control group underwent only an incision without cochlea ablation.Mice were tested for ABR thresholds 4 month later to assess hearing sensitivity by comparing the ABR before and after operation.Results In the experimental group,auricle reflection disappeared after operation and ABR waves couldn't be detect.In the control group,the result of hearing test was normal.Conclusion Mouse cochlea ablation is a reliable method for establishing a stable auditory deprived animal model of mouse by the pinna inferior approach.It can be used to the research of auditory centre plasticity induced by auditory deprived.