• Journal of the Optical Society of Korea
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• 제20권2호
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• pp.269-275
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• 2016

This study has investigated the feasibility of 980-nm low-energy pulsed near-infrared laser stimulation to evoke auditory responses, as well as the effects of radiant exposure and pulse duration on auditory responses. In the experiments, a hole was drilled in the basal turn of the cochlea in guinea pigs. An optical fiber with a 980-nm pulsed infrared laser was inserted into the hole, orientating the spiral ganglion cells in the cochlea. To model deafness, the tympanic membrane was mechanically damaged. Acoustically evoked compound action potentials (ACAPs) were recorded before and after deafness, and optically evoked compound action potentials (OCAPs) were recorded after deafness. Similar spatial selectivity between optical and acoustical stimulation was found. In addition, OCAP amplitudes increased with radiant exposure, indicating a photothermal mechanism induced by optical stimulation. Furthermore, at a fixed radiant exposure, OCAP amplitudes decreased as pulse duration increased, suggesting that optical stimulation might be governed by the time duration over which the energy is delivered. Thus, the current experiments have demonstrated that a 980-nm pulsed near-infrared laser with low energy can evoke auditory neural responses similar to those evoked by acoustical stimulation. This approach could be used to develop optical cochlear implants.

• 대한물리치료과학회지
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• 제3권1호
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• pp.907-918
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• 1996

Evoked potentials(EP) are defined as electric responses of the nerves system to sensory stimulation. EPs are used mainly to test conduction in the visual, auditory, and somatosensory systems, especially in the central parts of these systems. Somatosensory evoked potentials (SEP) are the potentials elicited by stimulation of peripheral nerves and recorded at various sites along the sensory pathway. SEPs types consist mainly of SEPs to electric stimulation of arm or leg nerves. SEPs to arm stimulation are usually recorded simultaneously from clavicular, cervical, and scalp electrodes; SEPs to leg stimulation are recorded from lumbar, low thoracic, and scalp electrodes. Subject variables that have practical impotance are age, limb length, body height, and temperature. General clinical interpretation of abnormal SEPs wave decreases of peripheral conduction time, and abolition of SEPs recorded from different levels to identify lesions of peripheral nerves, plexus, nerve root, spinal cord, cauda equina, hemispheric brainstem, and cerebral parts of the somatosensory pathway.

• Annals of Clinical Neurophysiology
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• 제2권2호
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• pp.101-106
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• 2000

Background and Purpose : Brainstem auditory evoked potentials(BAEPs) are responses of the brainstem by auditory stimulation. Vertebrobasilar transient ischemic attacks is the disease that occurs by insufficient circulation in the region of brainstem. The purpose of this study is to know the factors influencing the changes of BAEPs in vertebrobasilar transient ischemic attacks. Methods : The subject of study was 96 patients diagnosed as vertebrobasilar transient ischemic attacks. Patients were divided into two groups according to the BAEPs findings. Their age, sex, presence of hypertension, diabetes, hyperlipidemia, heart disease, neurologic findings, previous stroke, previous vertebrobasilar transient ischemic attacks, smoking and alcohol drinking, and time period between symptom onset and testing were compared. Results : There were no significant differences in age, sex, and presence of hypertension, diabetes, hyperlipidemia, heart disease, previous stroke history, previous vertebrobasilar transient ischemic attack, smoking, and alcohol drinking between two groups. The presence of abnormal neurologic findings in the first examination and time period between symptom onset and testing were significantly different between normal BAEPs group and abnormal BAEPs one(P<0.05). Conclusions : The factors influencing the changes of BAEPs were presence of abnormal neurologic findings and time period between symptom onset and testing. These findings suggest that BAEPs test should be performed in acute stage of ischemic attack.

• 감성과학
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• 제16권4호
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• pp.503-508
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• 2013

본 연구에서는 집중력이 중요한 학령기 아동을 대상으로 '비 집중 상태'와 '집중 상태'에 대한 뇌파의 차이를 분석하기 위해 비선형 해석 방법의 하나인 반복 정량 분석(Recurrence Quantification Analysis, RQA)을 이용하였다. 건강한 아동 21명(남성 12명, 여성 9명)을 대상으로, 청각 자극이 나오는 시점 전 500msec를 '비 집중상태' 자극 후 500msec를 '집중 상태'로 실험을 진행하였다. 실험결과 반복 정량 분석의 파라미터 값은 '비 집중 상태'보다 '집중 상태'가 큰 것을 확인하였다(p < 0.05). 또한, 상태에 따른 유발 전위의 반복궤적과 색상 반복궤적을 도식화하여 비선형 특성을 확인하였고, '비 집중 상태'보다 '집중 상태'일 때 뇌가 복잡한 특징을 나타내는 것을 알 수 있었다. 본 실험을 통하여 청각 자극에 대한 비 집중 집중 시 뇌의 비선형 특성을 반복 정량 분석을 통해 해석할 가능성을 확인하였다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1992년도 학술논문발표회 논문집 제11권 1호
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• pp.3-8
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• 1992

The theory of subjective preference with temporal and spatial factors which include sound signals arriving at both ears is described. Then, auditory evoked potentials which may relate to a primitive subjective response namely subjective preference are discussed. According to such fundamental phenomena, a workable model of human auditory-brain system is proposed. For eample, important subjective attributes, such as loudness, coloration, threshold of preception of a reflection and echo distrubance as well as subjective preference in relation to the initial time delay gap between the direct sound and the first reflection, and the subsequent reverberation time are well described by the autocorrelation function of source signals. Speech clarity, subjective diffuseness as well as subjective preference are related to the magnitude of inter-aural crosscorrelation function (IACC). Even the caktail party effects may be eplained by spatialization of human brain, i.e., independence of temporal and spatial factors.

• 대한의용생체공학회:의공학회지
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• 제17권2호
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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.

• 대한의용생체공학회:의공학회지
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• 제30권4호
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• pp.306-310
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• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• 생물정신의학
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• 제24권4호
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• pp.188-195
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• 2017

Objectives Schizophrenia is characterized by disturbances in perception and cognition. Attenuated mismatch negativity (MMN) reflects central auditory dysfunction in schizophrenia. The aim of this study is to compare MMN changes before and after treatment in schizophrenia patients and to assess their association with treatment response. Methods Twenty-three schizophrenia patients underwent an oddball paradigm. MMN was calculated by the difference waveforms of the event-related potentials (ERPs) elicited by subtracting standard from deviant stimulus. The clinical symptoms were measured by the Positive and Negative Syndrome Scale (PANSS), the Psychotic Symptom Rating Scale (PSYRATS). Follow-up evaluation was conducted when the PANSS total score decreased by 30% or more (treatment response group) or before discharge (non-response group). Results The treatment response group showed significantly larger MMN amplitude improvement and latency reduction than the non-response group after treatment (Fz ; mean amplitude p = 0.035, FCz ; p = 0.041). The auditory hallucination group showed shorter latency than that of the group without hallucinations. Additionally, auditory hallucination was associated with prolonged MMN latency and shortened after treatment in the auditory hallucination response group (Fz ; p = 0.048). Conclusions These results suggest that the attenuated MMN amplitude reflects the progression of the disease. The increment of MMN amplitude and shortening of latency after treatment may reflect cognitive functional recovery of central auditory sensory processing.

• 재활복지공학회논문지
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• 제7권1호
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• pp.45-50
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• 2013

최근, 동물에 대한 객관적 이명 유무 검사인 GPIAS (gap prepulse inhibition of acoustic startling) 방법이 보고된바 있으나 동물과 달리 큰 자극음에 의한 놀람 반응 (startling response)을 사람에게서 측정하는 것은 어렵기 때문에, 청성 유발 반응과 같은 뇌파 신호를 측정하는 것이 사람 이명 검사법 연구에 보다 적합하다. 본 연구에서는 GPIAS 방법에서 사용하는 gap prepulse 기반의 소리 자극법을 자유롭게 적용할 수 있으며, 청각 심리학적 현상인 이명과 연관된 대뇌 피질 활동을 반영하는 청성 후기 반응 (auditory late latency response, ALLR) 뇌파를 간편하게 측정할 수 있는 청성 후기 반응 측정 시스템을 구현하였다. 또한, 구현된 시스템을 정상 청력을 가진 8인의 피험자에게 적용하는 실험을 통해 gap prepulse 기반의 소리자극에 의한 청성 후기 반응의 N1-P2 첨두치 크기를 측정하였고, gap prepulse에 의한 N1-P2 억제율 현상을 확인 및 평가하였다. 이를 통해, 구현된 청성 후기 반응 측정 시스템이 향후 gap prepulse 소리 자극법에 기반한 객관적 이명 검사법 연구 및 검증 도구로서 이용될 수 있음을 확인하였다.

• Journal of Audiology & Otology
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• 제25권4호
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• pp.199-208
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• 2021

Background and Objectives: No known studies have investigated the influence of stimulus polarity on the Auditory Brainstem Response (ABR) elicited from level-specific (LS) chirp. This study is important as it provides a better understanding of the stimulus polarity selection for ABR elicited from LS chirp stimulus. We explored the influence of stimulus polarity on the ABR from LS chirp compared to the ABR from click at 80 dBnHL in normal-hearing adults. Subjects and Methods: Nineteen adults with normal hearing participated. The ABRs were acquired using click and LS chirp stimuli using three stimulus polarities (rarefaction, condensation, and alternating) at 80 dBnHL. The ABRs were tested only on the right ear at a stimulus rate of 33.33 Hz. The ABR test was stopped when the recording reached the residual noise level of 0.04 μV. The ABRs amplitudes, absolute latencies, inter-peak latencies (IPLs), and the recorded number of averages were statistically compared among ABRs at different stimulus polarities and stimuli combinations. Results: Rarefaction polarity had the largest ABR amplitudes and SNRs compared with other stimulus polarities in both stimuli. There were marginal differences in the absolute latencies and IPLs among stimulus polarities. No significant difference in the number of averages required to reach the stopping criteria was found. Conclusions: Stimulus polarities have a significant influence on the ABR to LS chirp. Rarefaction polarity is recommended for clinical use because of its larger ABR peak I, III, and V amplitudes than those of the other stimulus polarities.