• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.14-17
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• 1996

Evoked Potentials signals occur as a result of neuroelectric responses of the brain to sensory stimulation. In this paper, to analysis such signals we utilize a time-frequency analysis technique called wavelet transform. The wavelet analysis is performed based on a single prototype function,which can be thought of as a bandpass filter. Because the wavelet transform in a fine temporal analysis decomposes time-varying signals in EP into a dilated lowpass and a contracted highpass components, EP signal fetures can be obtained and analysed quantitatively at the levels of resolution. In the results, we analyze the VEP signal with the wavelet transform.

• Journal of Audiology & Otology
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• 제25권3호
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• pp.152-158
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• 2021

Background and Objectives: Balance control is maintained in stationary and dynamic conditions, with coordinated muscle responses generated by somatosensory, vestibular, and visual inputs. This study aimed to investigate how the vestibular system is affected in the presence of an optical illusion to better understand the interconnected pathways of the visual and vestibular systems. Subjects and Methods: The study involved 54 young adults (27 males and 27 females) aged 18-25 years. The recruited participants were subjected to the cervical vestibular evoked myogenic potentials (cVEMP) test and video head impulse test (vHIT). The cVEMP and vHIT tests were performed once each in the absence and presence of an optical illusion. In addition, after each test, whether the individuals felt balanced was determined using a questionnaire. Results: cVEMP results in the presence of the optical illusion showed shortened latencies and increased amplitudes for the left side in comparison to the results in the absence of the optical illusion (p≤0.05). When vHIT results were compared, it was seen that the right lateral and bilateral anterior canal gains were increased, almost to 1.0 (p<0.05). Conclusions: It is thought that when the visual-vestibular inputs are incompatible with each other, the sensory reweighting mechanism is activated, and this mechanism strengthens the more reliable (vestibular) inputs, while suppressing the less reliable (visual) inputs. As long as the incompatible condition persists, the sensory reweighting mechanism will continue to operate, thanks to the feedback loop from the efferent vestibular system.

• 대한청각학회지
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• 제25권3호
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• pp.152-158
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• 2021

Background and Objectives: Balance control is maintained in stationary and dynamic conditions, with coordinated muscle responses generated by somatosensory, vestibular, and visual inputs. This study aimed to investigate how the vestibular system is affected in the presence of an optical illusion to better understand the interconnected pathways of the visual and vestibular systems. Subjects and Methods: The study involved 54 young adults (27 males and 27 females) aged 18-25 years. The recruited participants were subjected to the cervical vestibular evoked myogenic potentials (cVEMP) test and video head impulse test (vHIT). The cVEMP and vHIT tests were performed once each in the absence and presence of an optical illusion. In addition, after each test, whether the individuals felt balanced was determined using a questionnaire. Results: cVEMP results in the presence of the optical illusion showed shortened latencies and increased amplitudes for the left side in comparison to the results in the absence of the optical illusion (p≤0.05). When vHIT results were compared, it was seen that the right lateral and bilateral anterior canal gains were increased, almost to 1.0 (p<0.05). Conclusions: It is thought that when the visual-vestibular inputs are incompatible with each other, the sensory reweighting mechanism is activated, and this mechanism strengthens the more reliable (vestibular) inputs, while suppressing the less reliable (visual) inputs. As long as the incompatible condition persists, the sensory reweighting mechanism will continue to operate, thanks to the feedback loop from the efferent vestibular system.

• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.985-994
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• 2000

Objective : There are some advantages of trigeminal evoked potential(TEP) recording compared to other somatosensory evoked potential(SSEP) recordings. The trigeminal sensory pathway has a pure sensory nerve branch, a broader receptive field in cerebral cortex, and a shorter pathway. Despite these advantages, there is little agreement as to what constitutes a normal response and what wave forms truly characterize the intraoperative TEP. This study presents the normative data of TEP recorded on the epidural surface of the rat with a platinum ball electrode. Materials & Methods : Under general anesthesia with urethane, the adult Sprague-Dawley male rats(300-350g) were given electrical stimulation with two stainless steel electrodes which were inserted into the subcutaneous layer of the area around whiskers. A reference electrode was positioned in the temporalis muscle ipsilateral to the recording site. Results : TEPs were recorded in the Par I area of somatosensory cortex and recorded most apparently on the point of 2mm posterior from the bregma and 6mm lateral from the midline. The typical wave form consisted of 5 peaks (N1-P1-N2-P2-N3 according to emerging order, upward negativity). Each latency to corresponding peaks was not influenced by the different intensities of stimulation, especially from 1 to 5mA. Average latencies of 5 peaks were in the following order ; 7.7, 11.1, 15, 22.3, 29.4ms. There was also no significant difference between latencies before and after administration of muscle relaxant(pancuronium). For the electrophysiological localization of recorded waves, the action potential of a single unit was recorded with glass microelectrode(filled with 2M NaCl, $3-5M{\Omega}$) in the thalamus of rat. A sharp wave was recorded in the VPM nucleus, in which the latency was shorter than that of N1. This suggests that all 5 peaks were generated by neural activities in the suprathalamic pathway. Conclusion : In terms of recording near-field potentials, our data also suggests that TEP in the rat may be superior to other SSEPs. In overall, these results may afford normative data for the studies of supratentorial lesions such as hydrocephalus or cerebral ischemia which can have an influence on near-field potentials.

• Annals of Clinical Neurophysiology
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• 제1권2호
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• pp.112-117
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• 1999

부중심소엽 주변의 경막하 전극들에서 기록한 PTSEP는 전극의 위치에 따라 다양한 파형을 나타내며, 파형의 최대치는 주로 부중심소엽의 후 상부에 위치한다. 특히 최대값이 주변보다 확연히 차이 나며 10uV이상의 파형으로 기록될 경우는 40 msec에서 양극성을 나타낸다. 또한 주변의 전극과 상역전을 형성할 수 있는데 최대 전극의 뒤에서 형성될 경우는 더욱 분명한 상역전을 관찰할 수 있다. 따라서 경막하전극을 통한 PTSEP는 내측 반구의 부중심소엽 주변의 위치를 파악하는데 도움을 줄 수 있다고 생각된다.

• 대한두개안면성형외과학회지
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• 제21권4호
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• pp.244-248
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• 2020

The infraorbital nerve is a branch of the trigeminal nerve. Injury to the infraorbital nerve can be caused by trauma, including various facial fractures. Due to this nerve injury, patients complain of numbness and pain in the entire cheek, the ala of nose, and upper lip. In general, spontaneous sensory recovery is expected after decompressive surgery. If nerve transection is confirmed, however, neurorrhaphy is typically performed. Here, we present a case in which microsurgery was not performed in a patient with Sunderland grade V avulsion injury of the infraorbital nerve due to a facial bone fracture. Gradual nerve function recovery was confirmed to be possible with conservative treatment and rehabilitation alone. These findings suggest that the nerve function recovery can be expected with conservative treatment, even for severe nerve injury for which microsurgery cannot be considered.

• Journal of Yeungnam Medical Science
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• 제18권1호
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• pp.67-74
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• 2001

정상 성인 남녀 36명(남:여=23:13)을 대상으로 LFCN의 SSEP검사를 시행한 결과로서 다음과 같은 결론을 얻을 수 있었다. 1. MP의 진단에 있어서는 $P_0$, $N_1$의 절대잠복기 뿐만 아니라 좌 우측 잠복기의 차이값($DP_0$, $DN_1$을 비교하여 보는 것이 더욱 중요하며 그 차이는 모두 2 msec 이하였다. 2. $P_0N_1$의 진폭만으로 비정상과 정상의 기준을 정할 수는 없으나 좌 우측 평균 진폭의 차이는 1.6배 이하였다. 3. $P_0(N_1)$, $DP_0(DN_1)$, 그리고 A(DA)에 있어 남녀군 간의 차이는 없었다.