Bio-Medical Materials and Engineering - Volume 24, issue 6

Authors: Xu, Lisheng | Yao, Yang | Wang, Hao | He, Dianning | Wang, Lu | Jiang, Yongsheng

Article Type: Research Article

Abstract: Pulse wave contains much information on a cardiovascular system. Pulse wave variability during exercise is of great significance as it reflects more information combining with pulse wave under stationary state. This paper studied the morphology variability of radial pulse wave during exercise. Radial pulse waves were collected from 30 subjects with two pressure pulse sensors worn at the wrists of the right and left hands, respectively. Electrocardiography (ECG) was also detected synchronously. After data preprocessing and feature point extraction, the variability of several parameters of pulse wave and ECG were analyzed. It is notable that pulse rate (PR) and heart …rate (HR) change synchronously. During the exercise period, both systolic phase and diastolic phase of a radial pulse shorten but the latter is more obvious. The amplitude of the dicrotic notch decreases and even turns negative. Aligning the radial pulse waveforms together, the radial pulse waveforms prior to, during and after exercise coincide with each other except for some details like the tidal wave which fades away during exercise. Show more

Keywords: Pulse morphology, exercise, radial pulse wave

DOI: 10.3233/BME-141187

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3605-3611, 2014

Authors: Yoo, Ji Won | Lee, Dong Ryul | Sim, Yon Ju | You, Joshua H. | Kim, Cheol J.

Article Type: Research Article

Abstract: Sensorimotor control dysfunction or dyskinesia is a hallmark of neuromuscular impairment in children with cerebral palsy (CP), and is often implicated in reaching and grasping deficiencies due to a neuromuscular imbalance between the triceps and biceps. To mitigate such muscle imbalances, an innovative electromyography (EMG)-virtual reality (VR) biofeedback system were designed to provide accurate information about muscle activation and motivation. However, the clinical efficacy of this approach has not yet been determined in children with CP. The purpose of this study was to investigate the effectiveness of a combined EMG biofeedback and VR (EMG-VR biofeedback) intervention system to improve muscle …imbalance between triceps and biceps during reaching movements in children with spastic CP. Raw EMG signals were recorded at a sampling rate of 1,000 Hz, band-pass filtered between 20–450 Hz, and notch-filtered at 60 Hz during elbow flexion and extension movements. EMG data were then processed using MyoResearch Master Edition 1.08 XP software. All participants underwent both interventions consisting of the EMG-VR biofeedback combination and EMG biofeedback alone. EMG analysis resulted in improved muscle activation in the underactive triceps while decreasing overactive or hypertonic biceps in the EMG-VR biofeedback compared with EMG biofeedback. The muscle imbalance ratio between the triceps and biceps was consistently improved. The present study is the first clinical trial to provide evidence for the additive benefits of VR intervention for enhancing the upper limb function of children with spastic CP. Show more

Keywords: Virtual reality, EMG visual feedback, neuromotor control, muscle imbalance, cerebral palsy

DOI: 10.3233/BME-141188

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3613-3618, 2014

Authors: Chung, Soon-Cheol | Choi, Mi-Hyun | Park, Sung-Jun | Lee, Jung-Chul | Jeong, Ul-Ho | Baek, Ji-Hye | You, Ji-Hye | Choi, Young Chil | Lim, Dae-Woon | Yi, Jeong-Han | Kim, Hyung-Sik

Article Type: Research Article

Abstract: In this study, a tactile stimulator that could separately or simultaneously display the vibrotactile and pressure sense was developed. The developed system consisted of a control unit, a drive unit, and an actuator, and can be operated with PC or manually. This system quantitatively controls the stimulation parameters such as the stimulation intensity, duration, frequency, and stimulation type. A preliminary electroencephalogram (EEG) experiment for three types of stimulation (vibrotactile, pressure sense, vibrotactile + pressure sense) highlights that the system could be used in complex tactile cognitive studies. An event-related desynchronization (ERD) and synchronization (ERS) were measured at the area of …C3 and C4 for all three types of stimulation, and a clear response was identified in the contralateral somatosensory area from the brain topology. Therefore, it is expected that this system could be widely used in single and complex human tactile cognition and perception studies for vibrotactile and pressure sensation. Show more

Keywords: Tactile stimulator, vibration, pressure, simultaneous stimulation, electroencephalogram

DOI: 10.3233/BME-141189

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3619-3627, 2014

Authors: Zhang, Cheng | Zhang, Guanghao | Rong, Wei | Wang, Aihua | Wu, Changzhe | Huo, Xiaolin

Article Type: Research Article

Abstract: Demyelination is part of the cascading secondary injury after the primary insult and contributes to the loss of function after spinal cord injury (SCI). Oligodendrocyte precursor cells (OPCs) are the main remyelinating cells in the central nervous system (CNS). We explored whether oscillating field stimulation (OFS) could efficiently promote OPC differentiation and improve remyelination after SCI. SD rats with SCI induced by the Allen method were randomly divided into two groups, the SCI+OFS group and SCI group. The former group received active stimulator units and the latter group received sham (inoperative) stimulator units. Additionally, rats that only received laminectomy were …referred as the sham group. The electric field intensity was 600μV/mm, and the polarity was alternated every 15 minutes. The results showed that the SCI+OFS rats had significantly less demyelination and better locomotor function recovery after 12-weeks treatment. The OFS treatment significantly increased the number of Gal C-positive OPCs after 2-weeks treatment. Furthermore, these rats had higher protein expression of oligodendroglial transcription factors Olig2 and NKx2.2. These findings suggest OFS can promote locomotor recovery and remyelination in SCI rats and this effect may be related to the improved differentiation of OPCs in the spinal cord. Show more

Keywords: Oligodendrocyte precursor cells, remyelination, oscillating field stimulation, spinal cord injury, rat

DOI: 10.3233/BME-141190

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3629-3636, 2014

Authors: Xiong, Shi | Cheng, Chen | Wu, Xia | Guo, Xiaojuan | Yao, Li | Zhang, Jiacai

Article Type: Research Article

Abstract: Recent studies have shown that working memory (WM) performance can be improved by intensive and adaptive computerized training. Here, we explored the WM training effect using Electroencephalography (EEG) neurofeedback (NF) in normal young adults. In the first study, we identified the EEG features related to WM in normal young adults. The receiver operating characteristic (ROC) curve showed that the power ratio of the theta-to-alpha rhythms in the anterior-parietal region, accurately classified a high percentage of the EEG trials recorded during WM and fixation control (FC) tasks. Based on these results, a second study aimed to assess the training effects of …the theta-to-alpha ratio and tested the hypothesis that up-regulating the power ratio can improve working memory behavior. Our results demonstrated that these normal young adults succeeded in improving their WM performance with EEG NF, and the pre- and post-test evaluations also indicated that WM performance increase in experimental group was significantly greater than control groups. In summary, our findings provided preliminarily evidence that WM performance can be improved through learned regulation of the EEG power ratio using EEG NF. Show more

Keywords: Electroencephalography, neurofeedback, working memory, power spectrum, self-regulation

DOI: 10.3233/BME-141191

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3637-3644, 2014

Authors: Su, Jing | Zhu, Wenting | Liu, Jing | Yin, Jian | Qin, Wei | Jiang, Changbin

Article Type: Research Article

Abstract: The aim of the present study was to research the role of nitric oxide (NO) as a mediator of alpha (α)-asarone effect at the pentylenetetrazol (PTZ)-induced epileptiform discharge in rat. α-Asarone that was injected intraperitoneally twenty minutes before PTZ injection suppressed the clonic discharge effectively and the significant actions lasted for 30 min with no change of clonic amplitude. Administration of α-asarone did not influence interictal discharge. Four kinds of NO regulators were administered, including non-selective NG-nitro-L-arginine methyl ester (L-NAME), selective neuronal nitric oxide synthase (nNOS) inhibitor, 7-nitroindazole (7-NI), inducible nitric oxide synthase (iNOS) inhibitor, aminoguanidine (AG) and NO substrate, …L-arginine (ARG) and their influence on the actions of α-asarone were studied, and all of the regulators were administered fifteen minutes before α-asarone injection. L-NAME and 7-NI reversed the anticlonic activity of α-asarone, and a significant increase of clonic activity was induced by L-NAME later in L-NAME + .α-asarone + PTZ group. There were no significant differences between AG + α-asarone + PTZ and α-asarone + PTZ group. L-ARG played a dual role in this study. It aggravated clonic discharge in the early stage but relieved interictal discharge in the late stage compared with PTZ group alone, and the beneficial effect of α-asarone was also reversed. All the above results suggest that nNOS/NO pathway mediates the anticonvulsant effect of α-asarone, and NO played a biphasic role in PTZ modeling process, while iNOS was unrelated to the inhibition effect of α-asarone on PTZ induced epileptiform activity. Show more

Keywords: Alpha-asarone, epileptiform activity, nitric oxide synthase, pentylenetetrazol

DOI: 10.3233/BME-141192

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3645-3655, 2014

Authors: Zhang, Guanghao | Huo, Xiaolin | Wu, Changzhe | Zhang, Cheng | Duan, Zhongping

Article Type: Research Article

Abstract: Bioelectrical impedance phase angle has been recommended as a tool to assess nutrition state, but there are no measuring devices have been specially designed for hospital residents. In this study, a system was established for the measurement of bioelectrical impedance phase angle. The electrical composition, calculation method and measuring method of this system are presented in this paper. Experiments showed excellent performance of this system in measuring impedance made of resistors and capacitors. The designed system was also used to measure the bioelectrical impedance phase angle of both healthy subjects and patients with malnutrition, and the results demonstrated that the …phase angle of patients with malnutrition is lower than that of healthy subjects (P < 0.01 for male and P < 0.05 for female). These results suggest that phase angle has the potential to be a useful tool for the quantitative assessment of nutritional status. Show more

Keywords: Phase angle, bioelectrical impedance, nutritional status

DOI: 10.3233/BME-141193

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3657-3664, 2014

Authors: Yang, Banghua | Han, Zhijun | Zan, Peng | Wang, Qian

Article Type: Research Article

Abstract: Classification methods are a crucial direction in the current study of brain-computer interfaces (BCIs). To improve the classification accuracy for electroencephalogram (EEG) signals, a novel KF-PP-SVM (kernel fisher, posterior probability, and support vector machine) classification method is developed. Its detailed process entails the use of common spatial patterns to obtain features, based on which the within-class scatter is calculated. Then the scatter is added into the kernel function of a radial basis function to construct a new kernel function. This new kernel is integrated into the SVM to obtain a new classification model. Finally, the output of SVM is calculated …based on posterior probability and the final recognition result is obtained. To evaluate the effectiveness of the proposed KF-PP-SVM method, EEG data collected from laboratory are processed with four different classification schemes (KF-PP-SVM, KF-SVM, PP-SVM, and SVM). The results showed that the overall average improvements arising from the use of the KF-PP-SVM scheme as opposed to KF-SVM, PP-SVM and SVM schemes are 2.49%, 5.83 % and 6.49 % respectively. Show more

Keywords: Kernel fisher, posterior probability, support vector machine, brain computer interface, common spatial pattern

DOI: 10.3233/BME-141194

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3665-3673, 2014

Authors: Chen, Xiaoyan | Lv, Xinqiang | Du, Meng

Article Type: Research Article

Abstract: The electrode polarization effects on bioelectrical impedance measurement at low-frequency cannot be ignored. In this paper, the bioelectrical data of mice livers are measured to specify the polarization effects on the bio-impedance measurement data. We firstly introduce the measurement system and methodology. Using the depolarization method, the corrected results are obtained. Besides, the specific effects of electrode polarization on bio-impedance measurement results are investigated using comparative analysis of the previous and posterior correction results from dielectric spectroscopy, Cole-Cole plot, conductivity and spectroscopy of dissipation tangent. Experimental results show that electrode polarization has a significant influence on the characteristic parameters of …mouse liver tissues. To be specific, we see a low-frequency limit resistance R0 increase by 19.29%, a reactance peak XP increase by 8.50%, a low-frequency limit conductivity Kl decrease by 17.65% and a dissipation peak tangent decrease by 160%. Show more

Keywords: Electrode polarization, depolarization correction, impedance measurement, low-frequency

DOI: 10.3233/BME-141195

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3675-3683, 2014

Authors: Woo, Seong Tak | Lee, Gihyoun | Jung, Eui Sung | Lim, Hyung-Gyu | Seong, Ki Woong | Lee, Jyung Hyun | Kim, Myoung Nam | Cho, Jin-Ho

Article Type: Research Article

Abstract: The microphone in a fully implantable hearing device (FIHD) is generally implanted under the skin covering the temporal bone. However, the implanted microphone can be affected by the skin, which causes both sound attenuation and distortion, particularly at high frequencies. As the degree of attenuation and distortion through the skin is severe, speech quality evaluation parameters are needed for the received signal when designing an implantable microphone. However, the performance of most implantable microphones is only assessed based on the sensitivity and frequency response. Thus, practical indicators based on human auditory characteristics are needed for an objective evaluation of the …performance of implantable microphones. In this study, a subcutaneously implantable microphone was designed, and its frequency response investigated using an in vivo experiment. Plus, to evaluate the objective indicators, the speech quality of the signals measured by the implanted microphone was calculated using a MATLAB program, and the indicators compared before and after implantation. Show more

Keywords: Implantable microphone, in vivo experiment, speech quality score, fully implantable hearing devices

DOI: 10.3233/BME-141196

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3685-3691, 2014