Bio-Medical Materials and Engineering - Volume 26, issue s1

Authors: Choi, Jung-Kyu | Cha, Eun-Jong | Kim, Kyung-Ah | Won, Yonggwan | Kim, Jung-Ja

Article Type: Research Article

Abstract: From a subject group of pes cavus, the purpose of this study was to evaluate the biomechanical characteristics of lower limbs, based on plantar foot pressure and electromyography (EMG) activities, by the effects on two kind of custom-made insoles. Ten individuals among thirty females with a clinical diagnosis of idiopathic pes cavus (mean age (SD): 22.3 (0.08) years) were selected for the study. The plantar foot pressure data and EMG activities of four lower limb muscles were collected, when subjects walked on a treadmill, under three different experimental conditions. The plantar foot pressure data was analyzed, after the bilateral foot …was divided into three areas of masks and into four sections of stance phase, to compare plantar foot pressure. The EMG activities were analyzed for integrated EMG (IEMG) value. The results show that plantar foot pressure concentrated in particular parts is decreased by custom-made insoles. In the case of EMG, all the muscle activities decreased significantly. The custom-made insoles dispersed pressure concentrated by the higher medial longitudinal arch and improved the efficient use of muscles. In particular, the extension structure in the forefoot of custom-made insoles was more efficient for pes cavus. Therefore, it could help patients to walk, by offering support to prevent the disease of pes cavus deformity, and to relieve the burden and fatigue in the lower limbs on gait. Show more

Keywords: Gait, custom-made insole, pes cavus, plantar foot pressure, EMG

DOI: 10.3233/BME-151362

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S705-S715, 2015

Authors: Kang, Ho Chul | Lee, Ju Hwan | Kim, Sung Min

Article Type: Research Article

Abstract: This study analyzes the moment of human main joints (knee and hip) for developing a wearable walking assistant robot. Experiments were performed on two steps to analyze motions. Three healthy males with no neural and musculoskeletal disorders volunteered to participate in this study. In the step up test, the maximum moment was 0.98±0.05 Nm/kg for the knee and 0.52±0.04 Nm/kg for the hip. In the sit-to-stand test, the maximum moment was 0.88±0.06 Nm/kg for the knee and 0.44±0.04 Nm/kg for the hip. The moment of the hip was significantly higher than the knee. In addition, the motion analysis results were …compared with proven validity and inverse dynamics analysis results. Experimental results showed that there was no significant difference in the absolute value or pattern. For the step up motion, after wearing Powered Gait Orthosis (PGO), the hip joint torque value (1.22 Nm/kg) was about 1.3 times greater than the knee joint torque value (0.96 Nm/kg). It indicates that the step up motion requires more power from the hip joint than the knee joint. Moreover, there was a significant torque value difference for before and after wearing the device. Show more

Keywords: Simulation, Powered Gait Orthosis (PGO), torque, joint

DOI: 10.3233/BME-151363

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S717-S727, 2015

Authors: Zhu, Yanhe | Zhang, Guoan | Zhang, Chao | Liu, Gangfeng | Zhao, Jie

Article Type: Research Article

Abstract: This paper introduces novel modern equipment—a lower extremity exoskeleton, which can implement the mutual complement and the interaction between human intelligence and the robot’s mechanical strength. In order to provide a reference for the exoskeleton structure and the drive unit, the human biomechanics were modeled and analyzed by LifeModeler and Adams software to derive each joint kinematic parameter. The control was designed to implement the zero-force interaction between human and exoskeleton. Furthermore, simulations were performed to verify the control and assist effect. In conclusion, the system scheme of lower extremity exoskeleton is demonstrated to be feasible.

Keywords: Lower extremity exoskeleton, controller, zero-force interaction, simulation

DOI: 10.3233/BME-151364

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S729-S738, 2015

Authors: Zhang, Hong | Xiao, Zheng | Lin, Shien-fong

Article Type: Research Article

Abstract: Sino-atrial node cells (SANCs) play a significant role in rhythmic firing. To investigate their role in arrhythmia and interactions with the atrium, computer simulations based on cellular dynamic mathematical models are generally used. However, the large-scale computation usually makes research difficult, given the limited computational power of Central Processing Units (CPUs). In this paper, an accelerating approach with Graphic Processing Units (GPUs) is proposed in a simulation consisting of the SAN tissue and the adjoining atrium. By using the operator splitting method, the computational task was made parallel. Three parallelization strategies were then put forward. The strategy with the shortest …running time was further optimized by considering block size, data transfer and partition. The results showed that for a simulation with 500 SANCs and 30 atrial cells, the execution time taken by the non-optimized program decreased 62% with respect to a serial program running on CPU. The execution time decreased by 80% after the program was optimized. The larger the tissue was, the more significant the acceleration became. The results demonstrated the effectiveness of the proposed GPU-accelerating methods and their promising applications in more complicated biological simulations. Show more

Keywords: Sino-atrial node, atrium, graphic processing units, optimization, computer simulations, dynamic model

DOI: 10.3233/BME-151365

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S739-S746, 2015

Authors: Wang, Dangxiao | Zhao, Siming | Li, Teng | Zhang, Yuru | Wang, Xiaoyan

Article Type: Research Article

Abstract: To evaluate the fidelity of the i Dental system and investigate its utility and performance on simulated drilling operations, user studies consisting of objective and subjective evaluations were performed. A voxel-based drilling simulation sub-system in the i Dental system was employed for evaluation. Twenty participants were enrolled to take part in the experiments and were divided into two groups: novice and resident. A combined evaluation method including objective and subjective methods was employed. The objective evaluation included two dental drilling tasks: caries removal operation and pulp chamber opening operation. In the subjective method, participants were required to complete a questionnaire …to evaluate the fidelity of the system after the operation task. Based on the structured global assessment scales in the questionnaire, the average subjective evaluation scores of the proposed metrics were greater than 4.5, demonstrating that the system operated above medium fidelity. Dentists expressed great interest and positive attitudes toward the potential of the i Dental system. The objective evaluation data including time spent and the volume of removed healthy and carious tissue were obtained. Although no significant differences could be found between the two groups, the volume of removed caries and the depth of pulp chamber insertion manifested small standard deviations. Evaluation results illustrated that dentists were willing to use the virtual reality training system. Several future research topics were identified, including increasing the task difficulty, improving the system fidelity and introducing appropriate finger rest points. Show more

Keywords: Dental simulation, virtual reality, haptic, dental drilling, user evaluation, objective evaluation

DOI: 10.3233/BME-151366

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S747-S756, 2015

Authors: Liu, Yixiang | Zang, Xizhe | Liu, Xinyu | Wang, Lin

Article Type: Research Article

Abstract: High compliant legs are essential for the efficient versatile locomotion and shock absorbency of humans. This study proposes a biped robot actuated by pneumatic artificial muscles to mimic human locomotion. On the basis of the musculoskeletal architecture of human lower limbs, each leg of the biped robot is modeled as a system of three segments, namely, hip joint, knee joint, and ankle joint, and eleven muscles, including both monoarticular and biarticular muscles. Each rotational joint is driven by a pair of antagonistic muscles, enabling joint compliance to be tuned by operating the pressure inside the muscles. Biarticular muscles play an …important role in transferring power between joints. Walking simulations verify that biarticular muscles contribute to joint compliance and can absorb impact energy when the robot makes an impact upon ground contact. Show more

Keywords: Biped robot, compliance, pneumatic artificial muscles, biarticular muscles

DOI: 10.3233/BME-151367

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S757-S766, 2015

Authors: Xu, Qin | Ye, Datian

Article Type: Research Article

Abstract: Auditory temporal integration (ATI) has been widely described in psychoacoustic studies, especially for loudness perception. Loudness increases with increasing sound duration for durations up to a time constant about 100 ~ 200 ms, and then loudness becomes saturated with more duration increase. However, the electrophysiological mechanism underlying the ATI phenomenon has not been well understood. To investigate ATI at the brainstem level of auditory system and its relationship to cortical and behavioral ATI, frequency follow response (FFR) was acquired in our study. Simultaneously, ATI in auditory cortex was evaluated by cortical response P1. Behavioral loudness and electrophysiological measures were estimated …from normal-hearing young adults for vowel /a/ whose durations varied from 50 ms to 175 ms. Significant effects of stimulus duration were found both on FFR and P1 amplitudes. Linear regression analysis revealed that as stimulus duration increased, brainstem FFR amplitude was significantly associated with cortical P1 amplitude and behavioral loudness, which confirmed the existence of temporal integration in auditory brainstem. Moreover, behavioral loudness ATI was better predicted using brainstem and cortical measures together than merely using each one separately, indicating an interplay and coordination for ATI across the three levels along auditory pathway. Show more

Keywords: Auditory temporal integration (ATI), frequency following response (FFR), cortical response P1, loudness

DOI: 10.3233/BME-151368

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S767-S778, 2015

Authors: Chinen, Koyu | Kinjo, Ichiko | Zamami, Aki | Irei, Kotoyo | Nagayama, Kanako

Article Type: Research Article

Abstract: Human body impedance analysis is an effective tool to extract electrical information from tissues in the human body. This paper presents a new measurement method of impedance using armpit electrode and a new equivalent circuit model for the human body. The lowest impedance was measured by using an LCR meter and six electrodes including armpit electrodes. The electrical equivalent circuit model for the cell consists of resistance R and capacitance C. The R represents electrical resistance of the liquid of the inside and outside of the cell, and the C represents high frequency conductance of the cell membrane. We propose …an equivalent circuit model which consists of five parallel high frequency-passing CR circuits. The proposed equivalent circuit represents alpha distribution in the impedance measured at a lower frequency range due to ion current of the outside of the cell, and beta distribution at a high frequency range due to the cell membrane and the liquid inside cell. The calculated values by using the proposed equivalent circuit model were consistent with the measured values for the human body impedance. Show more

Keywords: BIA, human body impedance, equivalent electrical circuit model, armpit electrode

DOI: 10.3233/BME-151369

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S779-S786, 2015

Authors: Sun, Xiang | Kim, Jin Young | Won, Yonggwan | Kim, Jung-Ja | Kim, Kyung-Ah

Article Type: Research Article

Abstract: Snoring, a common symptom in the general population may indicate the presence of obstructive sleep apnea (OSA). In order to detect snoring events in sleep sound recordings, a novel method was proposed in this paper. The proposed method operates by analyzing the acoustic characteristics of the snoring sounds. Based on these acoustic properties, the feature vectors are obtained using the mean and standard deviation of the sub-band spectral energy. A support vector machine is then applied to perform the frame-based classification procedure. This method was demonstrated experimentally to be effective for snoring detection. The database for detection included full-night audio …recordings from four individuals who acknowledged having snoring habits. The performance of the proposed method was evaluated by classifying different events (snoring, breathing and silence) from the sleep sound recordings and comparing the classification against ground truth. The proposed algorithm was able to achieve an accuracy of 99.61% for detecting snoring events, 99.16% for breathing, and 99.55% for silence. Show more

Keywords: Snoring, acoustic analysis, obstructive sleep apnea, sub-band spectra

DOI: 10.3233/BME-151370

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S787-S793, 2015

Authors: Wang, Lan | Li, Hailong | Wang, Zhengyu | Meng, Fandong

Article Type: Research Article

Abstract: During the rehabilitation process, it is essential to accurately judge a patient’s recovery in a timely manner. A reasonable and matched training program is significant in the development of rehabilitation system. This paper presents a new upper limb rehabilitation training system, which consists of an upper limb rehabilitation training device, a current detection circuit, a motor speed test circuit, a surface EMG (sEMG) sensor, and a dSPACE HIL simulation platform. The real-time output torque of the servo motor is calculated by using the motor’s real-time current and speed, in order to monitor the patient’s training situation. The signal of sEMG …is collected in real time and is processed with root mean square (RMS) to characterize the degree of muscle activation. Based on this rehabilitation system, maximum voluntary contraction (MVC) experiments, passive training experiments under different speeds, and active training experiments under different damping are studied. The results show that this new system performs real-time and accurate monitoring of a patient’s training situation. It can also assess a patient’s recovery through muscle activation. To a certain extent, this system provides a platform for research and development of rehabilitation medical engineering. Show more

Keywords: Surface EMG, upper limb rehabilitation system, rehabilitation assessment

DOI: 10.3233/BME-151371

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S795-S801, 2015