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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 31, Issue 6 - Dec 2010
Volume 31, Issue 5 - Oct 2010
Volume 31, Issue 4 - Sep 2010
Volume 31, Issue 3 - Jun 2010
Volume 31, Issue 2 - Apr 2010
Volume 31, Issue 1 - Feb 2010
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Introduction to EEG-Based Brain-Computer Interface (BCI) Technology
Im, Chang-Hwan ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 1~13
There are a great numbers of disabled individuals who cannot freely move or control specific parts of their body because of serious neurological diseases such as spinal cord injury, amyotrophic lateral sclerosis, brainstem stroke, and so on. Brain-computer interfaces (BCIs) can help them to drive and control external devices using only their brain activity, without the need for physical body movements. Over the past 30 years, several Bel research programs have arisen and tried to develop new communication and control technology for those who are completely paralyzed. Thanks to the rapid development of computer science and neuroimaging technology, new understandings of brain functions, and most importantly many researchers' efforts, Bel is now becoming 'practical' to some extent. The present review article summarizes the current state of electroencephalogram (EEG)-based Bel, which have been being studied most widely, with specific emphasis on its basic concepts, system developments, and prospects for the future.
Estimation of baroreflex sensitivity using pulse arrival time rather than systolic blood pressure measurement
Lee, Jong-Shill ; Chee, Young-Joon ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 14~19
Baroreflex sensitivity (BRS) is a parameter of the cardiovascular system that is reflected in changes in pulse interval (PD and systolic blood pressure (SBP). BRS contains information about how the autonomic nervous system regulates hemodynamic homeostasis. Normally the beat-to-beat SBP measurement and the pulse interval measured from the electrocardiogram (ECG) are required to estimate the BRS. We investigated the possibility of measuring BRS in the absence of a beat-to-beat SBP measurement device. Pulse arrival time (PAT), defined as the time between the R-peak of the ECG and a single characteristic point on the pulse wave recorded from any arterial location was measured by photoplethysmography. By comparing the BRS obtained from conventional measurements with our method during controlled breathing, we confirmed again that PAT and SBP are closely correlated, with a correlation coefficient of -0.82 to -0.95. The coherence between SBP and PI at a respiration frequency of 0.07-0.12 Hz was similar to the coherence between PAT and PI. Although the ranges and units of measurement are different (ms/mmHg vs. ms/ms) for BRS measured conventionally and by our method, the correlation is very strong. Following further investigation under various conditions, BRS can be reliably estimated without the inconvenient and expensive beat-to-beat SBP measurement.
Ear Canal Insertable Size Wireless Transceiver for Hearing Aid
Woo, Sang-Hyo ; Mohy-Ud-Din, Zia ; Yoon, Young-Ho ; Kim, Min-Kyu ; Lee, Jyung-Hyun ; Kim, Myoung-Nam ; Cho, Jin-Ho ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 20~26
The aim of this study was to test the feasibility of a wireless transceiver that can be inserted into the ear canal. The wireless technology could minimize the cosmetic problems of patients, and it can be applied to binaural hearing aids for improving speech perception. In order to implement the ear canal insertable transceiver, simple finite-difference time-domain (FDTD) simulations were carried out to determine the feasibility, and the hardware of the transceiver was implemented within the ear shell. The size of the implemented transceiver was only
, and it could successfully transmit signals to external devices. In order to measure the radiation pattern, a simple RF phantom was used, and the maximum attenuation from the phantom was observed to be 23 dB when the reference antenna was placed at a distance of 2 m from the transmitter.
Mean Phase Coherence as a Supplementary Measure to Diagnose Alzheimer's Disease with Quantitative Electroencephalogram (qEEG)
Che, Hui-Je ; Jung, Young-Jin ; Lee, Seung-Hwan ; Im, Chang-Hwan ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 27~32
Noninvasive detection of patients with probable Alzheimer's disease (AD) is of great importance for assisting a medical doctor's decision for early treatment of AD patients. In the present study, we have extracted quantitative electroencephalogram (qEEG) variables, which can be potentially used to diagnose AD, from resting eyes-closed continuous EEGs of 22 AD patients and 27 age-matched normal control (NC) subjects. We have extracted qEEG variables from mean phase coherence (MPC) and EEG coherence, evaluated for all possible combinations of electrode pairs. Preliminary trials to discriminate the two groups with the extracted qEEG variables demonstrated that the use of MPC as a supplementary or alternative measure for the EEG coherence may enhance the accuracy of noninvasive diagnosis of AD.
Influence of the Midsole Hardness on Shock Absorption along the Human Body during Running
Lee, Yong-Ku ; Kim, Yoon-Hyuk ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 33~39
During running, the human body experiences repeated impact force between the foot and the ground. The impact force is highly associated with injury of the lower extremity, comfort and running performance. Therefore, shoemakers have developed shoes with various midsole properties to prevent the injury of lower extremity, improve the comfort and enhance the running performance. The purpose of this study is to investigate influence of midsole hardness on shock absorption along the human body during running. Thirty two expert runners consented to participate in the study and ran at a constant speed with three different pairs of shoes with soft, medium and hard midsole respectively. Using accelerometers we measured the shock absorption from shoe heel to cervical vertebral column. In conclusion, at the shoe heel, shock was the greatest with the hard midsole. However because most shock was absorbed between shoe heel and the knee, notable influence of midsole was not detected upper knee. At shoe heel, regardless of midsole hardness, the shock of younger female was the greatest. The authors expect to apply this result for providing a guideline for utilizing proper midsole hardness for manufacturing age and gender-specific shoe.
Rule Weight-Based Fuzzy Classification Model for Analyzing Admission-Discharge of Dyspnea Patients
Son, Chang-Sik ; Shin, A-Mi ; Lee, Young-Dong ; Park, Hyoung-Seob ; Park, Hee-Joon ; Kim, Yoon-Nyun ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 40~49
A rule weight -based fuzzy classification model is proposed to analyze the patterns of admission-discharge of patients as a previous research for differential diagnosis of dyspnea. The proposed model is automatically generated from a labeled data set, supervised learning strategy, using three procedure methodology: i) select fuzzy partition regions from spatial distribution of data; ii) generate fuzzy membership functions from the selected partition regions; and iii) extract a set of candidate rules and resolve a conflict problem among the candidate rules. The effectiveness of the proposed fuzzy classification model was demonstrated by comparing the experimental results for the dyspnea patients' data set with 11 features selected from 55 features by clinicians with those obtained using the conventional classification methods, such as standard fuzzy classifier without rule weights, C4.5, QDA, kNN, and SVMs.
Net Center of Pressure Analysis during Gait Initiation Patient with Hemiplegia : a pilot study
Hwang, S.H. ; Park, S.W. ; Choi, H.S. ; Kim, Y.H. ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 50~55
Gait initiation is a transitional process from the balanced upright standing to the beginning of steady-state walking. Dysbalanced gait initiation often causes stroke patients to fall. The net center of pressure, measured by two triaxial force plates from twenty healthy subjects and two stroke patients, was investigated to assess asymmetry of gait initiation in hemiparetic subjects. The time interval and distance of the net center of pressure(CoP) moved from the initiation point to the toe off(S1) and from the toe off to the initial contact(S2) were calculated during gait initiation of normal and stroke patients. When the patient with right hemiplegia(A) initiated his gait with right foot, the time interval and the distance of the net CoP in S1 and S2 were smaller than that of normal subjects' values. However, he initiated the gait with left foot(unaffected side) the time interval and the distance of net CoP in S1 were larger than normative values. Differently, the patient with left hemiplegia(B) has shown that larger time interval and distance in S1 and smaller time interval and distance in S2 in both sides. His asymmetry(with which side the gait initiated) was not significant. It is too early to conclude that these results could be general characteristics of the stroke patients because the variations were large and moreover, the level of motor recovery of the patients was different. However, it is expected that these trials could help to set up the strategy of the therapy for the rehabilitation or prevention of fall in stroke patients.
Finite Element Analysis of a Newly Designed Screw Type Fixture for an Artificial Intervertebral Disc
Lim, Jong-Wan ; Yang, Hyun-Ik ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 56~66
The various total replacement artificial discs have developed because spinal fusion has shown a lesser mobility of an operated segment and an accelerated degeneration at adjacent discs. But almost artificial discs have not yet been reached on the substitute surgery of fusion because many problems such as those clinical success rates were not more than them of fusion have not solved. In this paper, vertically inserted assemble-screw fixture in vertebrae was proposed to improve the fixed capability of artificial disc. And also, to evaluate the design suitability of newly designed screw-type, including fixtures of commercial discs such as wedge and plate type, the 1/4 finite element model with a vertebra and various implanted fixtures were generated, and next, 3 bending motions such as flexion, bending and twisting under the moment of 10Nm and compression under the force of 1000N were considered, respectively and finally, FE analyses were performed. Results of three fixture types were compared, such as Range of Motion and maximal stress, and so on. For ROM, the screw type was average 58% less than the wedge type and was average 42% less than the plate type under all loading conditions. For average stress ratio at closer nodes between vertebra and each fixture, the wedge type was the lowest as minimum 0.02 in twisting, screw types were the highest as maximum 0.28 in compression. As the results of using cement material, it was predicted that the instability problem of the wedge type was better solved. The screw type which could be increased by implanting depth according to the number of assembling mid screws, showed that the decreased tendency of ROMs and maximal cancellous bone stresses. In further study, controlling the number of assembling screws that was suitable for a patient's bone quality, development of surgical tools and keeping on design supplementations, which will be able to develop the competitive artificial disc.
Study on Change of the Flatfoot's Ankle Angle in Sagittal plane before and after Wearing FFO
Park, K.Y. ; Park, S.H. ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 67~73
The foot performs an important function in supporting the body and keeping body balance. An abnormal walking habit breaks the balance of the human body as well as the normal function of the foot. The influence of a flatfoot(pes planus) occupies a considerable portion of the various causes resulting in the wrong walking habit. But, little studies has been done by the functional foot orthotics for the flat foot. The object of this study, therefore, is to propose a new approach method to reveal the effects of the improvement of the foot function by using orthotics. The essential point of this study is to measure and analyze the change of ankle angle in the sagittal plane for flat foot subjects wearing the orthotics. Before and after wearing the functional orthotics, the gait analysis of flat foot subjects was conducted in three experimental aspects : the change of ankle angle, the change of the total Ankle ROM and the difference of left & right ankle angle in the sagittal plane. 1. The average ankle angle differences of before-and-after wearing the orthotics have declined like this; left :
(p<0.05). 2. Total ankle ROM also showed decrease in both sides while the left side's is rather slight; left :
, right :
(p<0.05). 3. The difference of left and right ankle angle in the sagittal plane decreased by
(p<0.05). In result, it is confirmed that the functional foot orthotics have a significant effect on mechanical movement of ankle joint for flat foot. it is expected that this paper will be further studied and improved as a practical estimation method in the research on the effect of foot-orthotics.
3D Gait Analysis of Limb Salvage Patients with Osteoarticular Knee Allograft Reconstruction
Jang, Ik-Gyu ; Park, Hong-Seong ; Nam, Kyoung-Won ; Hong, Man-Bok ; Kim, Soo-Hyun ; Kim, Han-Soo ; Kang, Hyun-Guy ; Kim, Kwang-Gi ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 74~80
This paper presents the three dimensional gait analysis of the patients with osteoarticular knee allograft reconstruction. The gait analysis has been performed in some medical fields such as orthopedics and neurosurgery for the purpose of the rehabilitation of patients. However, to the author's knowledge, the analysis of gait for the patients with osteoarticular knee allograft reconstruction caused by tumor has not been reported. In this work, In this work, we confirmed the validity of this method by analyzing 50 samples per one gait cycle obtained from each of 3 patients and 3 normal persons. The motion capture was performed using six infrared cameras. The symmetry and stability of the gait patterns are investigated (patients' r=0.39, p<0.05, normal persons' r=0.65, p<0.05) respectively using the correlation coefficients and the standard deviations of the joint angles of the left and right legs. It also would be applied to the comparison analysis where artificial knee joint is transplanted.
Effect of Low-Energy Laser Irradiation on the Proliferation and Gene Expression of Myoblast Cells
Kwag, J.H. ; Jeon, O.H. ; Kang, D.Y. ; Ryu, H.H. ; Kim, K.H. ; Jung, B.J. ; Kim, C.H. ;
Journal of Biomedical Engineering Research, volume 31, issue 1, 2010, Pages 81~86
Laser irradiation is known to affect various tissues such as skin, bone, nerve, and skeletal muscle. Laser irradiation promotes ATP synthesis, facilitates wound healing, and stimulates cell proliferation and angiogenesis. In skeletal muscle, laser irradiation is related to the proliferation of skeletal muscle satellite cells. Normal skeletal muscle contains remodeling capacity from myogenic cells that are derived from mononuclear satellite cells. Their processes are activated by the expression of genes related with myogenesis such as muscle-specific transcription factors (MyoD and Myf5) and VEGF (vascular endothelial growth factor). In this study, we hypothesized that laser irradiation would enhance and regulate muscle cell proliferation and regeneration through modulation of the gene expressions related with the differentiation of skeletal muscle satellite cells.
myoblastic cells were exposed to continuous/non-continuous laser irradiation (660nm/808nm) for 10 minutes daily for either 1 day or 5 days. After laser irradiation, cell proliferation and gene expression (MyoD, Myf5, VEGF) were quantified. Continuous 660nm laser irradiation significantly increased cell proliferation and gene expression compared to control, continuous 808nm laser irradiation, and non-continuous 660nm laser irradiation groups. These results indicate that continuous 660nm laser irradiation can be applied to the treatment and regeneration of skeletal muscle tissue.