The study on the early diagnosis of hypoxic ischemic encephalopathy (HIE) in the newborns by fuzzy BP neural networks / 生物医学工程学杂志

This paper is aimed to study a method and feasibility of early diagnostic system using hypoxic ischemic encephalopathy (HIE) in the newborns. Fifteen non-invasive indicators with high sensitivity and specificity were selected for the early diagnosis of HIE on the basis of related researches from the literature and the researches in our laboratory. The diagnostic test was done with 140 cases with the HIE, using the fussy BP neural network experiment system. The initial results showed that the accuracy rate was 100% for the training set and 95% for the testing set, and the error rate was 5%. The data suggested that the fuzzy back-propagation neural networks, with the clinical comprehensive indicators, exhibited a high accuracy for the early diagnosis of HIE. This method provides an objective and convenient new way for the early clinical diagnosis of the HIE.

Application of pulse-coupled neural network combined with genetic algorithm on MR images of hypoxic-ischemic encephalopathy / 生物医学工程学杂志

This paper is to provide a basis for the establishment of an early diagnostic system for hypoxic-ischemic encephalopathy (HIE) by performing segmentation and feature extraction of lesions on the MR images of neonatal babies with HIE. The segmentation on MR images of HIE based on the genetic algorithm (GA) combined with a pulse-coupled neural network (PCNN) were carried out. There were better segmentation results by using PCNN segmentation based on GA than PCNN segmentation with fixed parameters. The data suggested that a PCNN based on GA could provide effective assistance for diagnosis and research.

Identification of mentality facticity based on multi-channel event-related potentials / 生物医学工程学杂志

This paper explores the use of multi-channel event-related potentials (ERP) to identify mentality facticity or detect lie. Some identifiably meaning information, such as subjects' name and birthday, were selected as concealed information to be identified, 15 subjects were tested by concealed information test (CIT) paradigm and their electroencephalographs (EEG) were recorded from 30 electrodes. In virtue of analysis on the statistically significant difference between multi-channel ERPs evoked by probe information and that evoked by irrelevant information, the P300 amplitudes of 15 electrodes were selected as F-test samples. The significant difference of feature sample values between probe and irrelevant information was applied to identify mentality facticity. The results indicate that P300 amplitudes evoked in many electrodes are significantly different between probe and irrelevant information (P < 0.01). According to the significant difference of space sample values between probe and irrelevant information, the detection correctness to probe information reaches to 93.3% and is better than that of methods based single-channel ERP. The method proposed has the advantages of non-invasion and better accuracy, which could be used to identify mentality facticity effectively.

A water-fat separation imaging method for the brain on low field magnetic resonance imaging / 药物分析学报

Water-fat separation is a particularly important problem for magnetic resonance imaging. Although many methods have been proposed, the reliability is still challenging. In this work, we have presented a method based on the combination of the branch-cut method and multigrid algorithm to get a more robust performance of water-fat separation. First, the branch-cut method is applied to identify residues, which violates the requirement that the interacting phase gradient around a closed path be zero. Residues and branches are marked to be zeros and filled to the weighting factor array. Then, the unwrapped phase array can be given by the multigrid algorithm. Finally, the Dixon method for water-fat separation is applied to the unwrapped phase array. Experiments for brain scanning on the 0.3T low field MRI system demonstrate the successful application of the proposed method.

Power spectrum analysis on the multiparameter electroencephalogram features of physiological mental fatigue / 生物医学工程学杂志

The aim of this experiment is to find a feasible impersonal index for analyzing the physiological mental fatigue level. Three characteristic parameters, relative power in different rhythm, barycenter frequency and power spectral entropy, are extracted from two channels' electroencephalogram (EEG) under two physiological mental fatigue states. Then relationships between such three parameters and physiological mental fatigue are analyzed to explore whether they can be of use for detecting (or monitoring) the mental fatigue level. The experiment results show that the relative power, barycenter frequency and power spectral entropy of EEG exhibit strong correlation with physiological mental fatigue level. While physiological mental fatigue level increases, the relative power in theta, alpha and beta rhythms, barycenter frequency and power spectral entropy of EEG decrease, but the relative power in delta rhythm of EEG increases. The relative power in four rhythms, barycenter frequency and power spectral entropy of EEG reflect the change of physiological mental fatigue level sensitively, and may hopefully be used as indexes for detecting physiological mental fatigue level.

Spectral entropy analysis of different alpha band rhythms in relation to hand motor imagery / 药物分析学报

The event-related desynchronization/synchronization(ERD/ERS) time courses of lower and upper alpha band rhythms during hand motor imagery are investigated respectively by Fourier Sectral Entropy (FSE) in this paper. By analyzing one group of BCI competition data, it was found that FSE within upper alpha band displays a pronounced increase and decrease over contralateral and ipsilaterai brain areas respectively at the onset of hand motor imagery, which is corresponding to the antagonistic ERD/ERS patterns in previous studies. Different from the upper alpha activity pattern, FSE within lower alpha band displays a consistent increase over both two hemispheres hand representative areas. The preliminary results show that FSE could disclose the different behaviors of the upper and lower alpha band rhythms so that a new idea with the complexity measure is provided to characterize functional dissociation of lower and upper frequency alpha rhythms in relation to hand motor imagery.

Study of dopamine transporter imaging on the brain of children with autism / 生物医学工程学杂志

This study was conducted to evaluate the applicability of 99mTc-2beta-[ N, N'-bis (2-mercaptoethyl) ethylenediamino]methyl,3beta(4-chlorophenyl)tropane(TRODAT-1) dopamine transporter(DAT) SPECT imaging in children with autism, and thus to provide an academic basis for the etiology, mechanism and clinical therapy of autism. Ten autistic children and ten healthy controls were examined with 99mTc-TRODAT-1 DAT SPECT imaging. Striatal specific uptake of 99mTc-TRODAT-1 was calculated with region of interest analysis according to the ratics between striatum and cerebellum [(STR-BKG)/BKG]. There was no statistically significant difference in semiquantitative dopamine transporter between the bilateral striata of autistic children (P=0.562), and between those of normal controls (p=0.573); Dopamine transporter in the brain of patients with autism increased significantly as compared with that in the brain of normal controls (P=0.017). Dopaminergic nervous system is dysfunctioning in the brain of children with autism, and DAT 99mTc-TRODAT-1 SPECT imaging on the brain will help the imaging diagnosis of childhcod autism.

Effects of rhubarb extracts on hyperexcitability of hippocampal CA1 neurons after fluid percussion injury / 药物分析学报

Objective To investigate the effects of rhubarb extracts, i.e. rhein and emodin, on the neuronal hyperexcitability and synaptic transmission, and to further reveal the mechanism of the secondary brain damage. Methods The fluid percussion injury (FPI) rat model and extracellular recording method were used. The evoked field potentials by stimulating Schaffer collaterals were collected from the ipsilateral (impact side) and the contralateral hippocampal CA1 areas of rat in vitro. And the field potentials, including the field excitatory postsynaptic potential and the population spike, were analyzed. Results After the impact was performed on the rat parietal cortex, the evoked field potentials in the ipsilateral hippocampus CA1 area were enhanced obviously. Rhubarb extracts reduced the slope of the field excitatory postsynaptic potential and the number of the population spike significantly while rhein and emodin increased the latency of the population spike obviously. Conclusion Rhubarb extracts, i.e. rhein and emodin, can depress the neuronal hyperexcitability, which suggests that rhein and emodin play an important role in protecting the central nervous system from neuronal damage after traumatic brain injury. FPI produces hyperexcitability of hippocampal CA1 neurons, probably by enhancing excitatory synaptic transmission.

Multiple mental tasks classification based on nonlinear parameter of mean period using support vector machines / 药物分析学报

Mental task classification is one of the most important problems in Brain-computer interface. This paper studies the classification of five-class mental tasks. The nonlinear parameter of mean period obtained from frequency domain information was used as features for classification implemented by using the method of SVM (support vector machines). The averaged classification accuracy of 85.6% over 7 subjects was achieved for 2-second EEG segments. And the results for EEG segments of 0.5s and 5.0s compared favorably to those of Garrett's. The results indicate that the parameter of mean period represents mental tasks well for classification. Furthermore, the method of mean period is less computationally demanding, which indicates its potential use for online BCI systems.

NONINVASIVE DETECTION OF BRAIN ACTIVITY VARIATION UNDER DIFFERENT DEPTH OF ANESTHESIA BY EEG COMPLEXITY / 药物分析学报

Objective To detect the change of brain activity under different depth of anesthesia (DOA)noninvasively. Methods The Lempel-Ziv complexity C(n) was used to analyze EEG and its four components (delta,theta, alpha, beta), which was recorded from SD rats under different DOA. The relationship between C(n) and DOA was studied. Results The C(n) of EEG will decrease while the depth of anesthesia increasing and vice versa. It can be used to detect the change of DOA sensitively. Compared with power spectrum, the change of C(n) is opposite to that of power spectru,. Only the C(n) of delta rhythm has obvious variations induced by the change of DOA, and the variations of delta is as similar as the EEG's. Conclusion The study shows that the desynchronized EEG is replaced by the synchronized EEG when rat goes into anesthesia state from awake, that is just the reason why complexity and power spectrum appear corresponding changes under different DOA. C(n) of delta rhythm dynamic change leads to the change of EEG, and the delta rhythm is the dominant rhythm during anesthesia for rats.

RESEARCH OF GENETIC POLYMORPHISM OF 5-HTT IN CHILDHOOD AUTISM / 药物分析学报

Objective To reveal the relationship between the 5-HTTLPR and the Chinese Han nationality children with CA, compared the distribution of the 5-HTTLPR between the Han Chinese children with CA and healthy Han Chinese children ,and analyzed the association between the 5-HTTLPR and clinical symptoms of the Han Chinese children with CA. Methods Genomic DNAs of fifty subjects including 25 autistic children and 25 controls were extracted from blood samples. PCR amplification using Oligonucleotide primers flanking 5-HTTLPR was performed. Results ① Three kinds of alleles including the S (short) allele, the L (long) allele and the VL allele were found , and the 5-HTTLPR genotypes shown were S/S, L/L, S/L and L/VL. ② Allele frequencies did not differ significantly in patient groups in comparison with the control sample. No significant difference was identified between the observed 5-HTTLPR genotype distribution of the patient groups and control group. ③ The distribution of homozygous and heterozygous subjects between the two groups differed significantly. ④ The genotypes of the 5-HTTLPR polymorphism correlated significantly with the Body Movement Factor. ⑤ The allele frequency of healthy Han Chinese population and that of healthy Japanese population were similar. The frequency of S allele in not only autistic subjects but also healthy children in this study was considerably more than that in Caucasians and the frequency of L allele in our subjects decreased correspondingly. Conclusion ① A significant difference in the allele frequency between the Han Chinese and Caucasian populations was found. ② The genotypes of the 5-HTTLPR polymorphism correlated significantly with the Body Movement Factor of the patients. ③ The homozygote and the L allele were positively relevant to CA and they might be the risk factors of CA. The heterozygote and the S allele were negatively relevant to CA and they might be the protective factors of CA.

A New Method for Monitoring the Status of Central Nervous System during General Anesthesia / 航天医学与医学工程

Objective To investigate the status of central nervous system(CNS)during general anesthesia using a new method of monitor.Methods Eighteen patients during general anesthesia were randomly chosen as the subjects.EEG signals of the patients were recorded as the subject was undergoing a surgical operation.Status of CNS of the patients during general anesthesia was monitored through the changes of Kolmogorov entropy(KE)of the EEG signals.Results Under the same kind of anesthesia measures,though most patients' CNS presented roughly the same status,but important differences were found in individual cases.Some presented depressed CNS status,some presented excited CNS status and others presented epileptic status.Conclusion The same general anesthesia may have different effects on different subjects.KE can reflect the status of the prefrontal cortex during general anesthesia.KE may be a new tool for monitoring the status of CNS during general anesthesia.

Monitoring on Depth of Anesthesia Basing on ? Rhythm Autocorrelation of EEG Signals / 航天医学与医学工程

Objective To explore the relationship between the depth of anesthesia and the autocorrelation of spontaneous EEG signals,and to find a new indicator which is easily calculated and involves fewer channels of ECG.Methods Eighteen patients with a surgical operation on chest or abdomen under general anesthesia served as the subjects.EEG signals of the patients were recorded.Change of ? rhythm of the EEG signal during general anesthesia was investigated by autocorrelation.Results The changes of autocorrelation indicator in channels Fp1-Cz and Fp2-Cz were obvious and consistent with the process of anesthesia;The changes of autocorrelation kcr in the two observed channels were almost synchronous.Conclusion The autocorrelation indicator kcr may be a new idea and a new tool for monitoring depth of anesthesia with fewer channels and the method will find wide prospect of application in clinic and in related scientific research work.

MEDICAL IMAGE SEGMENTATION BASED ON A MODIFIED LEVEL SET ALGORITHM / 药物分析学报

Objective To present a novel modified level set algorithm for medical image segmentation. Methods The algorithm is developed by substituting the speed function of level set algorithm with the region and gradient information of the image instead of the conventional gradient information. This new algorithm has been tested by a series of different modality medical images. Results We present various examples and also evaluate and compare the performance of our method with the classical level set method on weak boundaries and noisy images. Conclusion Experimental results show the proposed algorithm is effective and robust.

FULLY AUTOMATIC FRAMEWORK FOR SEGMENTATION OF BRAIN MRI IMAGE / 药物分析学报

Objective To propose an automatic framework for segmentation of brain image in this paper. Methods The brain MRI image segmentation framework consists of three-step segmentation procedures. First, Non-brain structures removal by level set method. Then, the non-uniformity correction method is based on computing estimates of tissue intensity variation. Finally, it uses a statistical model based on Markov random filed for MRI brain image segmentation. The brain tissue can be classified into cerebrospinal fluid, white matter and gray matter. Results To evaluate the proposed our method, we performed two sets of experiments, one on simulated MR and another on real MR brain data. Conclusion The efficacy of the brain MRI image segmentation framework has been demonstrated by the extensive experiments. In the future, we are also planning on a large-scale clinical evaluation of this segmentation framework.

A NEW MODEL AND IMPROVED CABLE FUNCTION FOR REPRESENTING THE ACTIVATING PERIPHERAL NERVES BY A TRANSVERSE ELECTRIC FIELD DURING MAGNETIC STIMULATION / 药物分析学报

Objective Previous studies of peripheral nerves activation during magnetic stimulation have focused almost exclusively on the cause of high external parallel electric field along the nerves, whereas the effect of the transverse component has been ignored. In the present paper, the classical cable function is modified to represent the excitation of peripheral nerves stimulated by a transverse electric field during magnetic stimulation. Methods Responses of the Ranvier nodes to a transverse-field are thoroughly investigated by mathematic simulation. Results The simulation demonstrates that the excitation results from the net inward current driven by an external field. Based on a two-stage process, a novel model is introduced to describe peripheral nerves stimulated by a transverse-field. Based on the new model, the classical cable function is modified. Conclusion Using this modified cable equation, the excitation threshold of peripheral nerves in a transverse field during MS is obtained. The modified cable equation can be used to represent the response of peripheral nerves by an arbitrary electric field.

Experimental study of excitation of peripheral nerves in transverse electric field stimulation / 生物医学工程学杂志

The classical cable function has been used to represent the response of peripheral nerves stimulated by external parallel electric field. Experiments show that peripheral nerves can be activated by perpendicular electric field induced by magnetic pulses, indicating that the activation mechanism needs to be thoroughly investigated. Several excitation properties of peripheral nerves in transverse-field were explored in the present paper. With a human's median nerve in vivo, stimulation threshold, excitation position and the relation between excitation threshold and fiber's radius were studied. The relation between stimulation threshold and stimulation duration was researched with sciatic nerves from toad in vitro. The experimental results verify that the modified cable function is much efficient than the classical cable function. The research will improve the nerve magnetic stimulating technique and be beneficial to further application.

Auto sleep staging and sleep quality estimation based on BP neural network / 生物医学工程学杂志

To estimate the sleep quality, a 3-layer BP neural network was studied. The EEG complexity and the power spectrum of sleep-multigraph served as the input vector of the network . All-night sleep-stage scoring was performed. Then several parameters (sleep period, shallow sleep period, deep sleep period, REM period, ratio of the wakeful period and sleep one) were defined to estimate the sleep quality. The experiments revealed that the estimated sleep condition was the same as the subjects' impression. The data on six cases of all-night sleep show that this method is available to estimate the sleep quality.

Digital watermarking for electroencephalogram compression / 生物医学工程学杂志

In this paper, digital watermarking and EEG compression are introduced firstly, and then a number of digital watermarking methods are explored to resolve the problem of integrality and authenticity in EEG compression. At last, the current state of this technique inside and outside country is summarized and future endeavors are discussed.