Objective Application of auditory brainstem response (ABR) in the study on the relationship of neonates with hypoxic-ischemic encephalopathy (HIE) and the children with hearing loss and auxiliary determine the prognosis of encephalopathy. Methods We prospectively selected neonates diagnosed as HIE in the department of neonatology of the Chengdu Women and Children Central Hospital from January, 2006 to June, 2008. Neonatal ABR was tested and the prognosis of neonates were observed through 3-year followed up in order to analyze the relationship between HIE severity and the severity of hearing handicap and the relationship between the severity of hearing handicap and prognosis. Statistical analysis was performed using SPSS 18.0. χ2 test was used to compare the rate between groups. Results 40 cases involving 80 ears were included, of which 33 cases accomplished the 3-year follow-up for prognosis. The results showed that, 86.3% HIE neonates had hearing handicap (mainly mild hearing loss, 40.0%). Medium-severe HIE groups had more serious hearing handicap than Mild HIE group with a statistical significance (continuity correction χ2=7.383, P=0.007). ABR results showed that, mild HIE is mainly manifested as I wave PL prolonged or poorly differentiated, accounting for 78.1%; medium - severe HIE are mainly manifested as III and V wave PL prolonged central segment abnormalities, accounting for 95.8%; the hearing threshold no more than 60 dB group had better prognosis than the hearing threshold more than 60 dB group prognosis (Fisher exact probability P=0.001). Conclusion ABR reflects that HIE severity and was positively related to the severity of hearing handicap. The more serious hearing loss in neonates is, the worse prognosis the neonates have. ABR can be used to assist the assessment of the prognosis of neonatal HIE.
Abstract This experiment was to study the feasibility from direct observation of muscle contraction of the lower extremity fromelectrical stimulation threshold of nerve fascicle in identifying the Iα intrafusal afferent fibers during selective posterior rhizotomy (SPR) and to investigate the clinical relationship between the muscle spasm and the electrical stimulation of nerve fascicles. The electrical stimulation threshold of all nerve fascicles in 36 cases during SPR were analysed statistically. The results showed that there was a significant difference between the electrical stimulation threshold of the severed nerve fascicles and intact nerve fascicles no matter the nerve root or each posterior nerve rootlet was examined. It was simple and reliable for surgeons to identify correctly the Iα intrafusal afferent fibers intraoperatively from direct observation of the electrical stimulation threshold of nerve fascicle.
ObjectiveTo evaluate the prognosis of photocoagulation and (or) cryotherapy for prethreshold type 1 and threshold disease of retinopathy of prematurity (ROP).MethodsThe data of 29 eyes of 15 infants who were diagnosed as with prethreshold type 1 or threshold disease of ROP from Jan 30th, 2003 to Jan 13th, 2005 were retrospectively analysed. Pre- and post-operative conditions of ROP were compared in the follow up. Any related local and systemic complications were recorded.ResultsIn 29 eyes which had undergone photocoagulation and (or) cryotherapy, ROP regressed completely in 19 (65.5%), remained dragged retina was found in 7 (24.1%), and retinal detachment was seen in 3 (103%). ROP regressed completely in 12 eyes (41.4%) after the initial treatment and in 7 eyes (24.1%) after the secondary treatment. During the treatment, temporary corneal haze was found in 2 eyes, vitreous hemorrhage occurred in 1 eye, and inadvertent photocoagulation at macular area happened in 1 eye. No systemic complications were found in all cases.ConclusionTimely treatment of photocoagulation and (or) cryotherapy for prethreshold type 1 and threshold disease of ROP may lead to famous prognosis.(Chin J Ocul Fundus Dis,2005,21:278-281)
Objective To introduce the multivariate random effects model (MREM) in the meta-analysis of diagnostic tests with multiple thresholds. Methods This paper expanded and extended the bivariate random effects model (BREM) to develop the MREM, and implemented it in the SAS Proc NLMIXED procedure. Results The MREM could obtain the study specific ROC curve for each study through empirical Bayes estimation, and the summary ROC curve located in between all study specific ROC curves evenly, while the BREM couldn’t obtain the study specific ROC curve. In addition, in the aspect of parameters estimation, the MREM didn’t depend on the choice of the diagnosis threshold and the type of SROC. The MREM could get only one SROC curve and its AUC was between the AUC of the 5 types of SROC from BREM, so it could avoid overestimation or underestimation. Conclusion The MREM can fully exploit the data, obtain stable and reliable results, and have a good application value in meta-analysis of diagnostic tests with multiple thresholds.
Objective Using cortex convulsions threshold detector and electrical stimulation in rats cortex convulsions threshold model, compare the efficacy and aging of domestic lamotrigine (LTG) and imported LTG. Methods Electrical stimulation convulsions threshold model in rats after stability, 40 rats were randomly divided into A、B、C、D groups,AandBgroup were divided into three different dose groups: domestic LTG low dose (12.5 mg/kg/d), middle dose (25 mg/kg·d), high dose group (37.5 mg/kg·d); imported LTG low doses (12.5 mg/kg·d), middle dose (25 mg/kg·d), high dose group (37.5 mg/kg·d); Carbamazepine middle dose group (72 mg/kg·d); the control group (normal saline 2 ml/time). Recording electrical stimulation in rats cortex convulsions threshold model after administration, compare the differences before and after the administration. Results Three different dose groups of domestic LTG and imported LTG all hadahigher level of electrical stimulation cortex convulsions threshold, and showedadose-response relationship. Onset time of LTG after administration was 1 to 2 hours, peak time was 3 to 4 hours, maintaining time was 8 to 10 hours. Conclusion LTG can improve cortex convulsions threshold in the electrical stimulated rats, there was no significant difference with carbamazepine, and showedadose-response relationship; Repeat dosing for 4 days, both domestic and imported LIG can maintain effective anticonvulsive effect, the efficacy and the aging of two groups of LTG have no significant difference (P＞0.05).
Electric and electronic products are required to pass through the certification on electrical safety performance before entering into the market in order to reduce electrical shock and electrical fire so as to protect the safety of people and property. The leakage current is the most important factor in testing the electrical safety performance and the test theory is based on the perception current effect and threshold. The traditional method testing the current threshold for perception only depends on the sensing of the human body and is affected by psychological factors. Some authors filter the effect of subjective sensation by using physiological and psychological statistical algorithm in recent years and the reliability and consistency of the experiment data are improved. We established an experiment system of testing the human body's current threshold for perception based on EEG feature analysis, and obtained 967 groups of data. We used wavelet packet analysis to detect α wave from EEG, and used FFT to do spectral analysis on α wave before and after the current flew through the human body. The study has shown that about 97.72% α wave energy changes significantly when electrical stimulation occurs. It is well proved that when the EEG feature identification is applied to test the human body current threshold for perception, and meanwhile α wave energy change and human body sensing are used together to confirm if the current flowing through the human body reaches the perception threshold, the measurement of the human body current threshold for perception could be carried out objectively and accurately.
It is difficult to distinguish the inferior alveolar nerve (IAN) from other tissues inside the IAN canal due to their similar CT values in the X image which are smaller than that of the bones. The direct reconstruction, therefore, is difficult to achieve the effects. The traditional clinical treatments mainly rely on doctors' manually drawing the X images so that some subjective results could not be avoided. This paper proposes the partition reconstruction of IAN canal based on shape features. According to the anatomical features of the IAN canal, we divided the image into three parts and treated the three parts differently. For the first, the directly part of the mandibular, we used Shape-driven Level-set Algorithm Restrained by Local Information (BSLARLI) segment IAN canal. For the second part, the mandibular body, we used Space B-spline curve fitting IAN canal's center, then along the center curve established the cross section. And for the third part, the mental foramen, we used an adaptive threshold Canny algorithm to extract IAN canal's edge to find center curve, and then along it established the cross section similarly. Finally we used the Visualization Toolkit (VTK) to reconstruct the CT data as mentioned above. The VTK reconstruction result by setting a different opacity and color values of tissues CT data can perspectively display the INA canal clearly. The reconstruction result by using this method is smoother than that using the segmentation results and the anatomical structure of mental foramen position is similar to the real tissues, so it provides an effective method for locating the spatial position of the IAN canal for implant surgeries.
Aiming at the single treatment and the design separation between treatment and assessment in electrotherapy equipment, a kind of system including low-intermediate frequency treatment and efficacy evaluation was developed. With C8051F020 single-chip microcomputer as the core and the circuit design and software programming used, the system realized the random switch of therapeutic parameters, the collection, display and data storage of pressure pain threshold in the assessment. Experiment results showed that the stimulus waveform, current intensity, frequency, duty ratio of the system output were adjustable, accurate and reliable. The obtained pressure pain threshold had a higher accuracy (<0.3 N) and better stability, guiding the parameter choice in the precise electrical stimulation. It, therefore, provides a reliable technical support for the treatment and curative effect assessment.
A de-noising method for electrocardiogram (ECG) based on ensemble empirical mode decomposition (EEMD) and wavelet threshold de-noising theory is proposed in our school. We decomposed noised ECG signals with the proposed method using the EEMD and calculated a series of intrinsic mode functions (IMFs). Then we selected IMFs and reconstructed them to realize the de-noising for ECG. The processed ECG signals were filtered again with wavelet transform using improved threshold function. In the experiments, MIT-BIH ECG database was used for evaluating the performance of the proposed method, contrasting with de-noising method based on EEMD and wavelet transform with improved threshold function alone in parameters of signal to noise ratio (SNR) and mean square error (MSE). The results showed that the ECG waveforms de-noised with the proposed method were smooth and the amplitudes of ECG features did not attenuate. In conclusion, the method discussed in this paper can realize the ECG de-noising and meanwhile keep the characteristics of original ECG signal.
Due to the characteristics and environmental factors, electrocardiogram (ECG) signals are usually interfered by noises in the course of signal acquisition, so it is crucial for ECG intelligent analysis to eliminate noises in ECG signals. On the basis of wavelet transform, threshold parameters were improved and a more appropriate threshold expression was proposed. The discrete wavelet coefficients were processed using the improved threshold parameters, the accurate wavelet coefficients without noises were gained through inverse discrete wavelet transform, and then more original signal coefficients could be preserved. MIT-BIH arrythmia database was used to validate the method. Simulation results showed that the improved method could achieve better denoising effect than the traditional ones.