• Title/Summary/Keyword: Evoked potential

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A Study on the Estimation Ergonomics Index for Evoked Potential (유발뇌파의 감성지수평가에 관한 연구)

  • 김창석
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.434-438
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    • 2004
  • This paper has proposed presumable method of ergonomics estimate index from evoked potential of visual stimulation for establishment a fixed ergonomics estimate index. The proposed method presumes continuance time and amplitude of ergonomics using prony method. Band characteristic of alpha and beta band, and that of background and evoked potential was analyzed using FFT method. And, that were presumed continuance time and amplitude of ergonomics using porny method. As a result of that proposed method presumed band characteristic, continuance time and amplitude of ergonomics, classification of ergonomics of impatient, rage and fear were practicable.

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An Influence of Electromagnetic Wave on the Evoked Potential in Human (인체에 있어서 전자파가 뇌의 유발전위에 미치는 영향)

  • Yoon, Chae-Hyun;Park, Hyung-Jun;Choi, Sang-Mook
    • Proceedings of the KIEE Conference
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    • pp.345-346
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    • 2007
  • In this study, an experimental method to be able to induce the evoked potential which was reflecting the activity of brain was designed, when the electromagnetic wave was exposed at human or not. The influence of the electromagnetic wave on each component of the evoked potential was discussed. Each component of N100, P100, N200, P300 and so on of the evoked potential was measured in the designed experimental method, And it was observed that the difference existed at each component when the electromagnetic wave was exposed and not exposed.

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Studies on the Detection of Visual-TEP with Average Method & the Improvement of TEP with DC-Drift Elinination (Average 기법에 의한 Visual-TEP의 검출과 DC-Drift 제거에 의한 TEP 신호개선에 관한 연구)

  • 배병훈;최정미
    • Journal of Biomedical Engineering Research
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    • v.15 no.2
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    • pp.135-142
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    • 1994
  • This paper presents average method to detect Visual-Transient Evoked Potential from the human scalp electric potential measured by the ElectroEncephaloGram. To confirm the validity of average method, the average-process is performed with both stimulated and no-stimulated potentials respectively, and both results are compared. The specific waveform, which is visual-transient evoked potential, is produced only in the case of stimulated potential. It was found that a dc-drift, due to instrumentation errors and other noises, can produce significant changes in the evoked-potential waveform. This can be removed with a high-pass filter (cut-off frequency=0.5Hz).

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Myoclonic status epilepticus in hypoxic ischemic encephalopathy which recurred after somatosensory evoked potential testing

  • Kim, Seongheon;Kim, Yeshin;Kim, Sunghun;Lee, Seo-Young
    • Annals of Clinical Neurophysiology
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    • v.19 no.2
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    • pp.136-140
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    • 2017
  • A 77-year-old male with amyotrophic lateral sclerosis had a hypoxic event. After resuscitation, generalized myoclonus appeared and resolved after two days. Five days after the hypoxic event, myoclonic seizures re-emerged right after performing a somatosensory evoked potential and persisted for ten days. Electroencephalogram revealed frequent bi-hemispheric synchronous spike and waves in the central areas. We suggest that somatosensory evoked potential testing may trigger myoclonic status epilepticus. Underlying cortical degeneration associated with amyotrophic lateral sclerosis could attribute to this phenomenon.

32-Channel EEG and Evoked Potential Mapping System (32채널 뇌파 및 뇌유전발전위 Mapping 시스템)

  • 안창범;박대준
    • Journal of Biomedical Engineering Research
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    • v.17 no.2
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    • pp.179-188
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    • 1996
  • A clinically oriented 32-channel electroencephalogram (EEG) and evoked potential (EP) mapping system has been developed EEG and EP signals acquired from 32-channel electrodes attached on the heroid surface are amplified by a pre-amplifier which is separated from main amplifier and is located near the patient to reduce signal attenuation and noise contamination between electrodes and the amplifier. The amplified signals are further amplified by a main amplifier where various filtering and gain contr61 are achieved An automatic artifact rejection scheme is employed using neural network-based EEG and artifact classifier, by which examination time is substantially reduce4 The continuously measured EEG sigrlals are used for spectral mapping, and auditory and visual evoked potentials measured in synchronous to the auditory and visual stimuli are used for temporal evoked potential mapping. A user-friendly graphical interface based on the Microsoft Window 3.1 is developed for the operation of the system. Statistical databases for comparisons of group and individual are included to support a statistically-based diagnosis.

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Visually evoked potential in children with mitochondrial respiratory chain defects (소아 사립체 질환에서 시각 유발전위검사의 유용성)

  • Song, Ji Eun;Kim, He Min;Lee, Sang-Chul;Park, Yoon-Gghil;Byeon, Suk-Ho;Lee, Young-Mock;Lee, Joon-Soo;Kim, Heung-Dong
    • Clinical and Experimental Pediatrics
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    • v.52 no.4
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    • pp.471-475
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    • 2009
  • Purpose : Mitochondrial disorders are a clinical entity characterized by diverse symptoms and signs of involvement of various systems. Furthermore, the disorders are known to show ophthalmologic manifestations as well as neurological findings. Visually evoked potential is a sensitive measure to check the integrity of the visual pathway. In this study, we have investigated the value of visually evoked potential in mitochondrial disorders with respiratory chain defects. Methods : Nineteen patients diagnosed with mitochondrial respiratory chain complex I defect as confirmed by spectrophotometric enzyme assay in muscle samples were enrolled for this study. The patients underwent a visually evoked potential study. We classified the results into four groups and compared these with clinical ophthalmologic findings. Results : Among the 19 patients, 14 showed abnormal visually evoked potential findings. Seven patients showed abnormal clinical ophthalmologic findings. All patients with abnormal ophthalmologic findings showed abnormal visually evoked potential findings. Among the 12 patients with normal ophthalmologic findings, seven showed abnormal results in visually evoked potential. Conclusion : Visually evoked potential study could be used as an effective screening tool for mitochondrial disorders to detect ophthalmologic and neurological abnormalities.

Evoked Potential Estimation using the Iterated Bispectrum and Correlation Analysis (Bispectrum 및 Correlation 을 이용한 뇌유발전위 검출)

  • Han, S.W.;Ahn, C.B.
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.12
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    • pp.113-116
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    • 1994
  • Estimation of the evoked potential using the iterated bispectrum and cross-correlation (IBC) has been tried for both simulation and real clinical data. Conventional time average (TA) method suffers from synchronization error when the latency time of the evoked potential is random, which results in poor SNR distortion in the estimation of EP waveform. Instead of EP signal average in time domain, bispectrum is used which is insensitive to time delay. The EP signal is recovered by the inverse transform of the Fourier amplitude and phase obtained from the bispectrum. The distribution of the latency time is calculated using cross-correlation between EP signal estimated by the bispectrum and the acquired signal. For the simulation. EEG noise was added to the known EP signal and the EP signal was estimated by both the conventional technique and bispectrum technique. The proposed bispectrum technique estimates EP signal more accurately than the conventional technique with respect to the maximum amplitude of a signal, full width at half maximum(FWHM). signal-to-noise-ratio, and the position of maximum peak. When applied to the real visual evoked potential(VEP) signal. bispectrum technique was able to estimate EP signal more distinctively. The distribution of the latency time may play an important role in medical diagonosis.

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Estimating Neuro-Pathway from Visual and Somatosensory Evoked Potential (유발전위를 이용한 뇌의 시감각 및 체성감각 인지영역 추정기술)

  • 배병훈;김동우
    • Journal of Biomedical Engineering Research
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    • v.15 no.4
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    • pp.481-488
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    • 1994
  • In this paper a study of neuro-pathway estimation based on visual and somatosensory evoked potential is given. The evoked potentials which are caused by visual and somatosensory stimulation are detected by an average method. The forward problem that is estimating a scalp potential from a given electrical source in the brain is solved by using a triple concentric spherical shell model of the head and a single current dipole model of the neuron activity. The inverse problem which calculates a source position is solved by a least square fit between the model predicted potential and a given evoked potential measurement. The similarities between estimated sensory neuro-pathways and physiological brain function regions are verified.

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Motor Evoked Potential and Somatosensory Evoked Potential Studies in Acquired Demyelinating Polyneuropathy (후천성 탈수초성 다발신경병증에서의 운동유발전위 및 체성감각유발전위 연구)

  • Kwon, Hyung-Min;Hong, Yoon-Ho;Oh, Dong-Hoon;Lee, Kwang-Woo
    • Annals of Clinical Neurophysiology
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    • v.6 no.1
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    • pp.20-25
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    • 2004
  • Background and Objectives: The proximal and distal nerve segments are preferentially involved in acquired demyelinating polyneuropathies (ADP). This study was undertaken in order to assess the usefulness of motor evoked potential (MEP) and somatosensory evoked potential (SSEP) in the detection of the proximal nerve lesion in ADP. Methods: MEP, SSEP and conventional NCS were performed in 6 consecutive patients with ADP (3 AIDP, 3 CIDP). MEP was recorded from abductor pollicis brevis and abductor hallucis using magnetic stimulation of the cortex and the cervical/lumbar spinal roots. SSEP were elicited by stimulating the median and posterior tibial nerves. Latency from cortex and cervical/lumbar roots, central motor conduction time (CMCT), EN1-CN2 interpeak latency were measured for comparison. Results: MEP was recorded in 24 limbs (12 upper and 12 lower limbs) and SSEP in 24 limbs (12 median nerve, 12 posterior tibial nerve). F-wave latency was prolonged in 25 motor nerves (25/34, 73.5%). Prolonged CML and PML were found in 41.7% (10/24) and 45.8% (11/24), respectively. Interside difference (ISD) of CMCT was abnormally increased in the upper extremity, 66.7% (4/6 pairs) in case of CML-PML. EN1-CN2 interpeak latency was abnormally prolonged in one median nerve (1/10) and LN1-P1 interpeak latency was normal in all posterior tibial nerves. Conclusions: MEP and SSEP may provide useful information for the proximal nerve and root lesion in ADP. MEP and SSEP is supplemental examination as well as complementary to conventional NCS.

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Effective Motor Evoked Potential Waveforms in Patients with Lower Extremity Weakness (다리에 힘이 없는 환자에서 효과적인 운동 유발전위 파형 측정에 대한 고찰)

  • Lim, Sung-Hyuk;Park, Sang-Ku;Han, Hung-Tae
    • Korean Journal of Clinical Laboratory Science
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    • v.48 no.1
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    • pp.41-48
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    • 2016
  • Motor evoked potential of spinal surgery is known to cause damage due to the movement path of the continuous scan operation and surgery can be performed with minimized disability after surgery. However, if it is not at all formed at the wave motion evoked potential can occur during surgery and, in some cases the size of the waveform to be measured is very small and intermittent. In this case, the surgery cannot provide information about whether there is neurological damage. Increased intensity of the wave-induced motion of the dislocation does not occur if it appears in a very small amplitude stimulus, but changing the inspection area that electrical stimulation of the waveform changes could not be found. However, stimulation of a wide area in the cerebral cortex was found to occur with a waveform in the patients who underwent examination. Through this study, we propose a useful motor evoked potential test. From November to December 2015 three spine surgery patients visited Samsung Medical Center as neurosurgery patients with omission discomfort, gait disturbance, and no symptom of strength before surgery. In spine surgery patients with motor grade weakness, when motor evoked potential waveform has not been measured, in examination of the site of electrical stimulation of the cerebral cortex from entering the C3+C5/C4+C6 or C3+C1/C4+C2 if by the activity of more motor neuron unit, it was found that the waveform is better formed.