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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Biomedical Engineering Research
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Journal DOI :
The Korea Society of Medical and Biological Engineering
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Volume & Issues
Volume 32, Issue 4 - Dec 2011
Volume 32, Issue 3 - Sep 2011
Volume 32, Issue 2 - Apr 2011
Volume 32, Issue 1 - Feb 2011
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Development of an Active Training System for Rehabilitation Exercise of Hemiplegic Patients
Lee, M.H. ; Son, J. ; Kim, J.Y. ; Kim, Y.H. ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 1~6
DOI : 10.9718/JBER.2011.32.1.001
An active training system has been developed to assist the upper extremity function in patients with spasticity. We also evaluated the performance of the developed assistive system in five normal subjects and one hemiplegic patient. The maximum voluntary contraction (MVC) tests for biceps brachii and triceps brachii were performed and the relationship between linear enveloped EMG signal and the elbow joint torque was found. In order to implement an active training, our system was designed to allow isokinetic movement only when the subject generates elbow joint motion larger than the pre-fixed threshold level. The proposed EMG-feedback control method could provide active exercises, resulting in better rehabilitation protocol for spastic patients.
Sensitivity Analysis and Optimization of Design Variables Related to an Algorithm for Loss of Balance Detection
Ko, B.K. ; Kim, K.H. ; Son, K. ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 7~14
DOI : 10.9718/JBER.2011.32.1.007
This study suggested an optimized algorithm for detecting the loss of balance(LOB) in the seated position. And the sensitivity analysis was performed in order to identify the role of each design variable in the algorithm. The LOB algorithm consisted of data processing of measured signals, an internal model of the central nervous system and a control error anomaly(CEA) detector. This study optimized design variables of a CEA detector to obtain improved values of the success rate(SR) of detecting the LOB and the margin time(MT) provided for preventing the falling. Nine healthy adult volunteers were involved in the experiments. All the subjects were asked to balance their body in a predescribed seated posture with the rear legs of a four-legged wooden chair. The ground reaction force from the right leg was measured from the force plate while the accelerations of the chair and the head were measured from a couple of piezoelectric accelerometers. The measured data were processed to predict the LOB using a detection algorithm. Variables S2, h2 and hd are related to the detector: S2 represents a data selecting window, h2 a time shift and hd an operating period of the LOB detection algorithm. S2 was varied from 0.1 to 10 sec with an increment of 0.1 sec, and both h2 and hd were varied from 0.01 to 1.0 sec with an increment of 0.01 sec. It was found that the SR and MT were increased by up to 9.7% and 0.497 sec comparing with the previously published case when the values of S2, h2 and hd were set to 4.5, 0.3 and 0.2 sec, respectively. Also the results of sensitivity analysis showed that S2 and h2 had considerable influence on the SR while these variables were not so sensitive to the MT.
Rebinning-Based Deterministic Image Reconstruction Methods for Compton Camera
Lee, Mi-No ; Lee, Soo-Jin ; Seo, Hee ; Nguyen, Van-Giang ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 15~24
DOI : 10.9718/JBER.2011.32.1.015
While Compton imaging is recognized as a valuable 3-D technique in nuclear medicine, reconstructing an image from Compton scattered data has been of a difficult problem due to its computational complexity. The most complex and time-consuming computation in Compton camera reconstruction is to perform the conical projection and backprojection operations. To alleviate the computational burden imposed by these operations, we investigate a rebinning method which can convert conical projections into parallel projections. The use of parallel projections allows to directly apply the existing deterministic reconstruction methods, which have been useful for conventional emission tomography, to Compton camera reconstruction. To convert conical projections into parallel projections, a cone surface is sampled with a number of lines. Each line is projected onto an imaginary plane that is mostly perpendicular to the line. The projection data rebinned in each imaginary plane can then be treated as the standard parallel projection data. To validate the rebinning method, we tested with the representative deterministic algorithms, such as the filtered backprojection method and the algebraic reconstruction technique. Our experimental results indicate that the rebinning method can be useful when the direct application of existing deterministic methods is needed for Compton camera reconstruction.
Accuracy Evaluation of the Alternative Site Blood Glucose Test Using Error Grid
Park, Kyung-Soon ; Cha, Eun-Jong ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 25~31
DOI : 10.9718/JBER.2011.32.1.025
Blood glucose information is important for self regulation in daily life, but the frequency of self test remains to be only 17%(9 tests/month) in Korea, mainly due to pain during blood sampling. The present study tried to validate the clinical efficacy of the forearm as an alternative sampling site with minimized pain. Capillary blood was sampled both on the index finger(
) and the forearm(
), immediately followed by glucose measurements in 531 subjects, 25 who visited the Health Enhancement Center of C University Hospital, then venous blood(
) was sampled for glucose test. The blood glucose concentration measured on the forearm was closer to the venous glucose than on the finger. The mean difference between
was only 10 mg/dL well within the internationally accepted error limit. Error grid analyses of
revealed that the number of data points in regions A and B took 100%, 99.8%, and 97.9%, respectively. These results demonstrate the forearm blood glucose test is not only accurate but also clinically valid. Therefore, the forearm blood glucose test can be a useful way of self managing the chronic diabetes with minimized sampling pain.
Development of the Insufflator for Endoscopic Surgery using the Fluidic System in Printed Circuit Board
Lee, Hee-Nam ; Kim, In-Young ; Chee, Young-Joon ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 32~36
DOI : 10.9718/JBER.2011.32.1.032
The insufflators in endoscopic surgery supply carbon dioxide to make the air-filled cavity in the abdomen. It contains many kinds of pneumatic and electronic parts and they are connected with the air tubes and electrical wires. The printed circuit boards (PCB) perform wiring, holding and cooling tasks in electronic systems. In this study, the PCB is used as the air channel for insufflators to decrease the cost, volume, and the malfunction according to aging of the device. Three layers of PCB made of FR4 are combined with prepreg as adhesive which has the internal airway channel according to the design. By mounting the pressure sensors and valves, the PCB based fluidic system is implemented. After calibration of flow sensor, the flow rate of the gas also can be measured. The climate test, temperature test, and biocompatibility test showed this idea can be used in insufflators for laparoscopic surgery.
Development and Assessment of Conductive Fabric Sensor for Evaluating Knee Movement using Bio-impedance Measurement Method
Lee, Byung-Woo ; Lee, Chung-Keun ; Cho, Ha-Kyung ; Lee, Myoung-Ho ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 37~44
DOI : 10.9718/JBER.2011.32.1.037
This paper describes the development and assessment of conductive fabric sensor for evaluating knee movement using bio-impedance measurement method. The proposed strip-typed conductive fabric sensor is compared with a dot-typed Ag/AgCl electrode for evaluating validity under knee movement condition. Subjects are composed of ten males(
) who have not had problems on their knee. The strip-typed conductive fabric sensor is analyzed by correlation and reliability between a dot-typed Ag/AgCl electrode and the strip-typed conductive fabric sensor. The difference of bio-impedance between a dot-typed Ag/AgCl electrode and the strip-typed conductive fabric sensor averages
As the p-value is under 0.0001 in 99% of t-distribution, the strip-typed conductive fabric sensor is correlated with a dot-typed Ag/AgCl electrode by SPSS software. The strip-typed conductive fabric sensor has reliability when it is compared with a dot-typed Ag/AgCl electrode because most of bio-impedance values are in
standard deviation by Bland-Altman Analysis. As a result, the strip-typed conductive fabric sensor can be used for assessing knee movement through bio-impedance measurement method as a dot-typed Ag/AgCl electrode. Futhermore, the strip-typed conductive fabric sensor is available for wearable circumstances, applications and industries in the near future.
Development of a Low-Noise Amplifier System for Nerve Cuff Electrodes
Song, Kang-Il ; Chu, Jun-Uk ; Suh, Jun-Kyo Francis ; Choi, Kui-Won ; Yoo, Sun-K. ; Youn, In-Chan ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 45~54
DOI : 10.9718/JBER.2011.32.1.045
Cuff electrodes have a benefit for chronic electroneurogram(ENG) recording while minimizing nerve damage. However, the ENG signals are usually contaminated by electromyogram(EMG) activity from the surrounding muscle, the thermal noise generated within the source resistance, and the electric noise generated primarily at the first stage of the amplifier. This paper proposes a new cuff electrode to reduce the interference of EMG signals. An additional middle electrode was placed at the center of cuff electrode. As a result, the proposed cuff electrode achieved a higher signal-to-interference ratio compared to the conventional tripolar cuff. The cuff electrode was then assembled together with closure, headstage, and hermetic case including electronic circuits. This paper also presents a lownoise amplifier system to improve signal-to-noise ratio. The circuit was designed based on the noise analysis to minimize the electronic noise. The result shows that the total noise of the amplifier was below
for a cuff impedance of
and the common-mode rejection ratio was 115 dB at 1 kHz. In the current study, the performance of nerve cuff electrode system was evaluated by monitoring afferent nerve signals under mechanical stimuli in a rat animal model.
The Effect of Adaptation to Sound Intensity on the Neural Metabolism in Auditory Pathway: Small Animal PET Study
Jang, Dong-Pyo ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 55~60
DOI : 10.9718/JBER.2011.32.1.055
Although sound intensity is considered as one of important factors in auditory processing, its neural mechanism in auditory neurons with limited dynamic range of firing rates is still unclear. In this study, we examined the effect of sound intensity adaptation on the change of glucose metabolism in a rat brain using [F-18] micro positron emission tomography (PET) neuroimaging technique. In the experiment, broadband white noise sound was given for 30 minutes after the [F-18]FDG injection in order to explore the functional adaptation of rat brain into the sound intensity levels. Nine rats were scanned with four different sound intensity levels: 40 dB, 60 dB, 80 dB, 100 dB sound pressure level (SPL) for four weeks. When glucose uptake during the adaptation of a high intensity sound level (100 dB SPL) was compared with that during adaptation to a low intensity level (40 dB SPL) in the experiment, the former induced a greater uptake at bilateral cochlear nucleus, superior olivary complexes and inferior colliculi in the auditory pathway. Expectedly, the metabolic activity in those areas linearly increased as the sound intensity level increased. In contrast, significant decrease interestingly occurred in the bilateral auditory cortices: The activities of auditory cortex proportionally decreased with higher sound intensities. It may reflect that the auditory cortex actively down-regulates neural activities when the sound gets louder.
The Analysis of GRF and joint angles of young and older adult by Vibration Stimulation on the Ankle-Joint in stair-descent activity
So, H.J. ; Kwak, K.Y. ; Kim, S.H. ; Yang, Y.S. ; Kim, N.G. ; Kim, D.W. ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 61~73
DOI : 10.9718/JBER.2011.32.1.061
The purpose of this study was to investigate changes in the center of pressure (COP), ground reaction force (GRF) and joint angles of elderly people and young people while stair-descent. The participants in this experiment were 5 elderly people and 5 young people, each of which was asked to descend stairs of three different heights (8 cm, 16 cm, and 32 cm). As they climbed down the stairs, they received vibration stimulation on the lower limb. The change of COP, GRF and joint angles were analyzed during the standing phase. COP decreased as the Achilles tendon and tibialis anterior tendon were vibrated. Vertical GRF increased as the Achilles tendon was vibrated, and the joint angle differed according to vibration stimulation conditions. These results mean that ankle joint, knee joint and hip joint were influenced by the vibrations on the lower limb as the participants descended the stairs. It was concluded that the vibration stimulation on the lower limb allowed the participants to efficiently climb down the stairs.
The evaluation of [F-18]FDG small animal PET as a functional neuroimaging technique with fear response experiment
Jang, Dong-Pyo ;
Journal of Biomedical Engineering Research, volume 32, issue 1, 2011, Pages 74~78
DOI : 10.9718/JBER.2011.32.1.074
Although recent studies have shown the usibility of [F-18]FDG small animal Positron Emission Tommography (PET) as a functional neuroimaging technique in behavioural small animal study, researches showing the detection power of functional changes in the brain are still limited. Thus, in the study, we performed [F-18]FDG small animal PET neuroimaging in the well-established fear behavioural experiment. Twelve rats were exposed on cat for 30 minutes after the [F-18]FDG injection. As a result, the brain activity in bilateral amygdala areas significantly increased in the fear condition. In addition, the fear condition evoked the functional activities of hypothalamus, which seemed to be related to the response to stress. These clear localization of fear related brain regions may reflect that a functional neuroimaging technique using [F-18]FDG small animal PET has functional detectibility enough to be applied in small animal behavioral research.