• 대한임상검사과학회지
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• 제43권1호
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• pp.19-25
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• 2011

The purpose of this study was to analyse brainstem auditory evoked potentials (BAEP) wave change data during microvascular decompression (MVD). The nerve function of Cranial Nerve VIII is at risk during MVD. Intraoperative monitoring of BAEP can be a useful tool to decrease the danger of hearing loss. Between January and December 2009, 242 patients had MVD for hemifacial spasm (HFS) and trigeminal neuralgia (TN). Among intraoperative BAEP changes, amplitude of V-V' was the most frequently observed during cerebellar retraction and decompression step of the MVD procedure. 138 patients (57%) had no BAEP change while 104 patients (42.98%) had BAEP change. 69 patients (28.5%) had Type A-I, 16 patients (6.6%) had Type A-II, 5 patients (2.1%) had Type B, and 13 patients (5.37%) had Type C. MVD is a surgical procedure to relieve the symptoms (e.g. pain, muscle twitching) caused by compression of a nerve by an artery or vein. During BAEP intraoperative monitoring, the surgical step is important in interpreting the changes of wave V. Several potential mechanisms of injury may affect the cochlear nerve, and complete loss of BAEP is often associated with postoperative hearing loss. Intraoperative BAEP monitoring may provide an early warning of hearing disturbance after MVD.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.189-192
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• 1995

In Visually Evoked Potentials(VEP) or Auditory Evoked Potentials(AEP), the components by the stimulation and the components which are irrelevant to the stimulation(noise or nonstationary spontaneous EEG) are mixed together. So one should average hundreds of EP waves to extract the components by the stimulation only. In this study, we have classified EP's, which are the responses of the different stimulations and different states of subjects. To classify the EP waves, the cross-correlation coefficients and neural network method(error back propagation) are used and compared.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 학술발표대회 논문집 제17권 1호
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• pp.291-296
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• 1998

In the experiment carried out on 20 college students, recorded were frontal, temporal and occipital EEG, skin conductance response, skin conductance level, heart rate and respiration rate during listening to two music fragments with different affective valences and white noise administered immediately after negative visual stimulation. Analysis of physiological patterns observed during the experiment suggests that affective auditory stimulation with music is able to selectively modulate autonomic and cortical activity evoked by preceding aversive visual stimulation and to restore initial baseline levels. On other hand, physiological responses to white noise, which does not possess emotion-eliciting capabilities, evokes response typical for orienting reaction after the onset of a stimulus and is rapidly followed by habituation. Observed responses to white noise were similar to those specific to attention only and had no evidence for any emotion-related processes. Interpretation of the obtained data is considered in terms of the role of emotional and orienting significance of stimuli, dependence of effects on the background physiological activation level and time courses of attention and emotion processes. Physiological parameters are summarized with regard to their potential utility in differentiation of psychological processes induced by auditory stimuli.

• Annals of Clinical Neurophysiology
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• 제23권2호
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• pp.69-81
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• 2021

Cortico-cortical evoked potential (CCEP) mapping is a rapidly developing method for visualizing the brain network and estimating cortical excitability. The CCEP comprises the early N1 component the occurs at 10-30 ms poststimulation, indicating anatomic connectivity, and the late N2 component that appears at < 200 ms poststimulation, suggesting long-lasting effective connectivity. A later component at 200-1,000 ms poststimulation can also appear as a delayed response in some studied areas. Such delayed responses occur in areas with changed excitability, such as an epileptogenic zone. CCEP mapping has been used to examine the brain connections causally in functional systems such as the language, auditory, and visual systems as well as in anatomic regions including the frontoparietal neocortices and hippocampal limbic areas. Task-based CCEPs can be used to measure behavior. In addition to evaluations of the brain connectome, single-pulse electrical stimulation (SPES) can reflect cortical excitability, and so it could be used to predict a seizure onset zone. CCEP brain mapping and SPES investigations could be applied both extraoperatively and intraoperatively. These underused electrophysiologic tools in basic and clinical neuroscience might be powerful methods for providing insight into measures of brain connectivity and dynamics. Analyses of CCEPs might enable us to identify causal relationships between brain areas during cortical processing, and to develop a new paradigm of effective therapeutic neuromodulation in the future.

• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.367-375
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• 2019

Hemifacial spasm (HFS) is due to the vascular compression of the facial nerve at its root exit zone (REZ). Microvascular decompression (MVD) of the facial nerve near the REZ is an effective treatment for HFS. In MVD for HFS, intraoperative neurophysiological monitoring (INM) has two purposes. The first purpose is to prevent injury to neural structures such as the vestibulocochlear nerve and facial nerve during MVD surgery, which is possible through INM of brainstem auditory evoked potential and facial nerve electromyography (EMG). The second purpose is the unique feature of MVD for HFS, which is to assess and optimize the effectiveness of the vascular decompression. The purpose is achieved mainly through monitoring of abnormal facial nerve EMG that is called as lateral spread response (LSR) and is also partially possible through Z-L response, facial F-wave, and facial motor evoked potentials. Based on the information regarding INM mentioned above, MVD for HFS can be considered as a more safe and effective treatment.

• 전자공학회논문지
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• 제50권6호
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• pp.287-293
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• 2013

인공와우는 유모세포의 손실로 청신격 자극이 되지 않을 경우, 삽입된 전극에 전기자극을 가함으로써 청감각을 회복하는 장치이다. 인공와우의 성능을 향상하기 위하여, 자극에 따른 정확한 신경반응을 이해하는 것이 매우 중요하고, 임상에서는 electrically evoked compound action potential (ECAP)을 측정하여 신경반응을 측정하고 있다. 본 연구에서는 실제 달팽이관과 유사한 3차원 달팽이관 유한요소 모델을 개발하고, 자극에 따른 신경반응을 측정할 수 있는 ECAP 알고리즘을 개발하였다. 개발된 3차원 달팽이관 모델을 이용하여, 전기 자극에 따른 ECAP 크기와 반응 잠복 시간을 측정하였으며, 측정된 결과 임상시험과 동물실험에서 측정된 ECAP 크기와 반응 잠복 시간과 유사한 값을 얻을 수 있었다. 본 3차원 달팽이관 모델은 전기 자극에 대한 신경 반응을 분석함으로써 인공 와우의 성능을 향상시키기 위한 전기자극 방식을 연구하는데 유용하게 이용될 수 있다.

• 수면정신생리
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• 제1권1호
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• pp.87-98
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• 1994

연구배경 : 정신분열증 환자들이 정보처리 과정의 문제가 있을 것이라는 가설을 지지해 주는 사건관련유발 전위인 P3의 이상을 보고하는 연구들이 있어 저자들은 정신분열증 환자들에게 청각사건관련유발 전위를 실시하여 P3의 이상을 확인하고자 하였다. 또한, 음성 및 양성 정신분열증환자에 P3의 차이가 있는지 비교하였으며, 가족력이나 전기충격경련요법, 밖에 임상양상과 P3와의 연관성을 알아보기 위하여 본 연구를 실시하였다. 방법 : DSM-III-R 진단기준에 맞는 정신분열증 환자 54명 (남자 31, 여자 23) 과 그 대조군 75 명 (남자 33, 여자 42) 을 대상으로 oddball paradigm 을 이용한 사건관련유발전위를 실시하여 P3의 잠복기와 진폭을 측정하였으며, 정신분열증의 인지기능이상을 알아볼 수 있는 프랑크푸르트 임상검사를 같이 실시하였다. 결과 : 정신분열증 환자의 P3 잠복기는 그 대조군에 비해 의미 있게 지연되어 있었으며, 또한 모든 진폭도 대조군에 비해 의미 있게 감소되어 있었다. 정신분열증 환자군에서 프랑크푸르트 임상검사의 10가지 임상증상 모두에서 통계적으로 유의하게 높은 점수를 보였다. PANSS의 종합점수에 따라 음성과 양성으로 나누어 비교한 결과, P3의 잠복기 및 진폭에서 의미 있는 차이가 발견되지 않았다. 또한, 정신과질환의 가족력의 유무에 따라, 전기 충격경련요법 유무에 따라 비교한 결과 의미 있는 차이를 발견할 수 없었다. 환자군에서 프랑크푸르트 임상검사의 임상증상, 그밖에 임상특성과 P3의 잠복기와 진폭 사이에 연관성을 발견할 수 없었다. 결론 : 본 연구의 결과로 정신분열증 환자들에서 선택적 주의집중 과정의 이상이 있을 것이고 추측할 수 있었으며, 임상양상이나 가족력 유무와 P3사이에 연관성이 없다는 것을 시사해 주었다.

• 대한의용생체공학회:의공학회지
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• 제15권4호
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• pp.383-388
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• 1994

일정한 단속 주파수(triggering frequency)를 지닌 청각자극의 반송 주파수(carrier ferquency, pure tone)를 1kHz에서 3kHz까지 0.5kHz단위로 증가시키면서, 이에 반응하는 뇌전위를 디지탈 EEG측정장치를 이용하여 총 7초 동안 1kHz의 sampling frequency로 컴퓨터로 전송하였다. 먼저 신호의 pseudo-phase space분석을 통해 뇌전위의 진폭특성을 파악하였다. 이러한 해석은 생리학적으로 밝져진 소리의 반송주파수와 소리의 크기 인지사이의 상관관계와 잘 일치함이 확인되었다. 또한 이 신호외 Lyapunov exponent 분석을 통해 신호의 발산 특성을 물리적으로 파악하고, 이러한 특성을 이미 여러가지 접근법에 의해 밝혀져 있는 생리학적 실험결과와 관련지어 해석함으로써 반송 주파수에 반응하는 뇌의 mechanism을 뇌전위 측정에 의해서 검출이 가능함을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.141-142
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• 2008

Hearing loss is the most common birth defect among infants. Yet most hearing-impaired children are not identified until 1 to 3 years of age - which is well beyond the critical period(6 month) for healthy speech and language development. However, if a hearing-impairment is identified and treated in its early stages, child's speech and language skills will be comparable to his or her normal- hearing peers. For these reasons, hearing screening at birth and routinely throughout childhood is extremely important. Auditory brain-stem response(ABR) is nowadays one of the most reliable diagnostic tools in the early detection of hard of hearing. In this study, we developed the system that detects auditory evoked potential using micro-processor. Furthermore, it is required to develop a portable system to measure in not only soundproof room but also nursery for infants.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권6호
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• pp.334-338
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• 2000

Even though it is not practical, yet there is a trend of the researches related to the anesthesia on the determination of depth of anesthesia and level of consciousness in the view point of neurophysiological aspects. That is, quantification of physiological signals which represent human brain function and pharmacological response could be used to find the level of consciousness based on the changes in physiological signals. This research was performed to analyze the relationship between parameters extracted from LAEP(long latency auditory evoked potential) and the amount of sedatives injected to the patients. Seventeen patients were participated for the experiment. Two different sedatives, midazolam and diazepam, were injected intramuscularly, and LAEPs caused by 1KHz and 2KHz auditory tone bust were obtained. It was found that amplitude of extracted parameters from LAEP, N100 and P300, were reduced as dose of sedatives were increased. Results of this study could be used for extracting more meaningful index and establishing algorithm for predicting changes of level of consciousness induced by sedatives.