Design and Implementation of Heart Sound Detection Device Based on MEMS MIC / 中国医疗器械杂志

The paper describes how to develop a digital heart sound signal detection device based on high gain MEMS MIC that can accurately collect and store human heart sounds. According to the method of collecting heart sound signal by traditional stethoscope, the system improves the traditional stethoscope, and a composite probe equipped with a MEMS microphone sensor is designed. The MEMS microphone sensor converts the sound pressure signal into a voltage signal, and then amplifies, converts with Sigma Delta, extracts and filters the collected signal. After the heart sound signal is uploaded to the PC, the Empirical Mode Decomposition (EMD) is carried out to reconstruct the signal, and then the Independent Component Analysis (ICA) method is used for blind source separation and finally the heart rate is calculated by autocorrelation analysis. At the end of the paper, a preliminary comparative analysis of the performance of the system was carried out, and the accuracy of the heart sound signal was verified.

Clinical Implication of High VOR Gain in Slow Harmonic Acceleration / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to verify if high vestibulo-ocular reflex (VOR) gain in slow harmonic acceleration (SHA) test can be considered as a hallmark of a distinct disease entity. We hypothesized that patients with high VOR gain in the SHA test can be classified as a distinct disease group and looked for evidence that can support this hypothesis. SUBJECTS AND METHOD: For this study, 306 patients who had undergone a rotation chair test were enrolled. We checked other VOR measurements (caloric test and step velocity) and clinical manifestation of the patients with high gain in SHA (HG group). The data were compared to those of the migraine associated vertigo (MAV), benign recurrent vertigo (BRV) and psychogenic dizziness (PsyD). RESULTS: An abnormally long time constant and a large response to the caloric test were found more frequently in the patient group with high gain in SHA. The incidence of high gain in SHA was significantly higher in MAV, BRV and PsyD. The clinical manifestation of HG group was not distinguishable from the effects of BRV and PsyD. But MAV was different from HG group. CONCLUSION: We failed to find any evidence that the patients with high gain in the SHA could be classified as a distinct disease group. It seems that high gain is not merely a non-specific or incidental finding but a reproducible finding that reflects an aspect of the subject's vestibular function. Also, the high gain in SHA is more suggestive of BRV or PsyD than MAV.

Design of 16-channel EEG signals preprocessor / 医疗卫生装备

In order to check out the cortical EEG signals of conscious and/or anesthetized rats, a 16-channel analog signals preprocessor is developed. This preprocessor can amplify and filter the primal EEG signals to transform them into ones with proper altitudes and high SNRs, and then they will be sent to the A.D converter. Some measures are taken in view of the signals' low frequencies, low SNRs and background with strong interference. When high gain made, such performances of the circuit are emphasized as low noise, low offset voltage, low gain error and heightened CMRR.