• Phonetics and Speech Sciences
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• v.7 no.3
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• pp.99-105
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• 2015

The current study investigates whether Korean-speaking adults show differential sensitivities to the sources of auditory stimuli (L1 Korean and L2 English) in utilizing VOT and f0 in the perceptual mode of L2 stops, and how the L2 proficiency interacts with the learners' low-level phonetic sensitivities in L2 perceptual mode. 48 Korean learners of English participated in the perception experiments where they rated the goodness of English /t/ and /d/ using an analogue scale. Two sets of stimuli (English and Korean sources) were prepared by manipulating VOT (6-steps) and f0 (5-steps) values of productions by an English male (L2 source condition) and a Korean male (L1 source condition). Findings showed that, in judging /t/-likeness, the listeners responded differently to the two auditory stimulus conditions by relying on VOT significantly more in English source condition than in Korean source condition. The listeners' English proficiency did not interact with these differential sensitivities to the auditory stimulus source either along the VOT dimension or the f0 dimension. The results of the current study suggest that low-level contextual information of the auditory source can affect the learners in faithfully being in the L2 perceptual mode.

• Child Health Nursing Research
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• v.15 no.3
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• pp.261-270
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• 2009

Purpose: The purpose of this study was to compare the result of one-way ANOVA with that of cross-correlation time series analysis in order to evaluate physiologic responses of premature infants to human voices. Methods: Four premature infants born prior to 32 weeks gestational age were included in the study. The Gould 4000TA Recording System recorded the preterm infant's heart and respiratory rate while they were listening to a pre-recorded voice recording. Each infant listened to both male and female voices (1 min each) at each testing session. Results: The results of both one-wayANOVA and cross-correlation time series analysis using heart and respiratory rate data were not consistent in some of premature infants. A cross-correlation time series analysis revealed that the responses of premature infant to vocal stimulation occurred at a varying number of seconds after the stimulus was presented and lasted for over 20-30 sec. Conclusion: The results indicate that a time series analysis can provide more detailed information on the rapidly changing physiologic status of premature infant to the auditory stimulus. In addition, the results provide an insight into an auditory responsitivity of premature infants to a naturally occurring sound, the human voice, in the neonatal intensive care unit.

• Korean Journal of Child Studies
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• v.38 no.3
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• pp.75-90
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• 2017

Objective: This study aimed to identify children's cognitive processing and performance characteristics while multiple task performance. It confirmed whether their multiple task performance and psychological refractory period (PRP) varied by task condition (stimulus onset asynchrony [SOA] and task difficulty) and stimulus modality. Methods: Seventy 5-year-olds were recruited. Multi-task tools were developed using the E-prime software. The children were required to respond to two stimuli (visual or auditory) presented with microscopic time difference and their response times (RTs) were recorded. Results: As the SOA increased, the RTs in the first task increased, while the RTs in the second task and PRP decreased. The RTs of the first and second tasks, and the PRP for difficult tasks, were significantly longer than those for easy tasks were. Additionally, there was an interaction effect between the SOA and task difficulty. Although there was no main effect of stimulus modality, task difficulty moderated the modality effect. In the high difficulty condition, the RTs of the first and second tasks and PRP for the visual-visual task were significantly longer than those for auditory-auditory task were. Conclusion: These results inform theoretical discussions on children's multi-task mechanism, and the loss of multiple task performance. Additionally, they provide practical implications and information on the composition of multi-tasks suitable for children in educational environments.

• Journal of Biomedical Engineering Research
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• v.34 no.2
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• pp.47-54
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• 2013

Electrical stimulation is delivered to auditory nerve (AN) through the electrodes in cochlear implant system. Neurogram is a spectrogram that includes information of neural response to electrical stimulation. We hypothesized that the similarity between a neurogram and an input-sound spectrogram could show how well a cochlear implant system works. In this study, we evaluated electrical stimulus configuration of CIS strategy using the computational model. The computational model includes stochastic property and anatomical features of cat auditory nerve fiber. To evaluate similarity between a neurogram and an input-sound spectrogram, we calculated Structural Similarity Index (SSIM). The results show that the dynamic range and the stimulation rate per channel influenced SSIM. Finally, we suggested the optimal configuration within the given stimulus CIS. We expect that the results and the evaluating procedure could be employed to improve the performance of a cochlear implant system.

• Therapeutic Science for Rehabilitation
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• v.5 no.1
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• pp.33-42
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• 2016

Objective : The purpose of this study was to verify the effects of auditory stimulus using music on unilateral neglect in patients with stroke. Methods : This study used a single subject (ABA) design. The subject who showed unilateral neglect caused by stroke received auditory stimulus using music for 60 minutes per sessions. A total of 20 sessions were conducted. The unilateral neglect was measured by the Star cancellation test and Line bisection test during each session, and Catherine Bergego Scale was used to evaluate the degree of unilateral neglect in daily life pre-and post-test. Also, Positive Affect and Negative Affect Schedule was used to test subject's emotional status. Results : During the intervention period, the results of the Star cancellation test and Line bisection test showed the trend of reduction of unilateral neglect symptom and the effects of intervention were maintained after intervention. After intervention, the results of CBS indicated decreased unilateral neglect symptom in activities of daily living and the results of PANAS indicated increased positive affect. Conclusions : The result of this study indicate that auditory stimulus has a positive effect on the unilateral neglect, and may be considered as alternative choice in clinical occupational therapy for reducing unilateral neglect.

• Journal of the Ergonomics Society of Korea
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• v.25 no.3
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• pp.67-75
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• 2006

HVIMs consists of simulated driver models implemented with series of mathematical functions and computerized vehicle dynamic models. To effectively model the perception process, as a part of driver models, psychophysical nonlinearity should be considered not only for the single-modal stimulus but for the stimulus of multiple modalities and interactions among them. A series of human factors experiments were conducted using the primary sensory of visual and auditory modalities to find out the effects of auditory cues in visual velocity estimation tasks. The variations of auditory cues were found to enhance/reduce the perceived intensity of velocity as the level changed. These results indicate that the conventional psychophysical power functions could not applied for the perception process of the HVIMs with multi-modal stimuli. 'Ruled surfaces' in a 3-D coordinate system(with the intensities of both kinds of stimuli and the ratio of enhancement, respectively for each coordinate) were suggested to model the realistic perception process of multi-modal HVIMs.

• Korean Journal of Biological Psychiatry
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• v.21 no.4
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• pp.168-174
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• 2014

Objectives Sensory gating dysfunctions in patients with schizophrenia and bipolar disorder have been investigated through two similar methods ; P50 suppression and prepulse inhibition paradigms. However, recent studies have demonstrated that the two measures are not correlated but rather constitute as distinct neural processes. Recent studies adopting spectral frequency analysis suggest that P50 suppression reflects the interaction between gamma and other frequency bands. The aim of the present study is to investigate which frequency component shows more significant interaction with gamma band. Methods A total of 108 mood disorder patients and 36 normal subjects were included in the study. The P50 responses to conditioning and test stimuli with an intra-pair interval of 500 msec were measured in the study population. According to P50 ratio (amplitude to the test stimulus/amplitude to the conditioning stimulus), the subjects with P50 ratio less than 0.2 were defined as suppressed group (SG) ; non-suppressed group (NSG) consisted of P50 ratio more than 0.8. Thirty-five and 25 subjects were included in SG and NSG, respectively. Point-to-point correlation coefficients (PPCCs) of both groups were calculated between two time-windows : the first window (S1) was defined as the time-window of one hundred millisecond after the conditioning auditory stimulus and the second window (S2) was defined as the time-window of 100 msec after the test auditory stimulus. Spectral frequency analysis was performed to investigate which frequency band results in the difference of PPCC between SG and NSG. Results Significant reduction of PPCC between S1 and S2 was observed in the SG (Pearson's r = 0.24), compared to PPCC of the NSG (r = 0.58, p < 0.05). In spectral frequency analysis, gamma band showed "phase-reset" and similar responses after the two auditory stimuli in suppressed and non-suppressed group. However in the case of alpha band, comparison showed significantly low PPCC in SG (r = -0.14) compared to NSG (r = 0.36, p < 0.05). This may be reflecting "phase-out" of alpha band against gamma band at approximately 50 msecs after the test stimulus in the SG. Conclusions Our study suggests that normal P50 suppression is caused by phase-out of alpha band against gamma band after the second auditory stimulus. Thus it is demonstrated that normal sensory gating process is constituted with attenuated alpha power, superimposed on consistent gamma response. Implications of preserved gamma and decreased alpha band in sensory gating function are discussed.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.4
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• pp.1032-1038
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• 2005

Using the 2-channel DROS SQUID (Korea Research Institute of Standards of Science, 1999), the present study was carried out to record changes elicited in the auditory cortex by acupuncture stimulus (right GB43, Xiaxi). Needle-retention and manual needle-twitching stimulation of GB43 and SP1 were done for acquiring the brain activities changed by acupuncture. Acupoint GB43 is known to be effective for the treatment of ear-related disease, such as deafness and tinnitus, and to be suspected to be related to the auditory cortex. Auditory evoked magnetic fields were recorded from the left hemisphere of five or four subjects, in response to contralateral ear stimulation by irregularly spaced 170msec long 1kHz tone busts (Korea Research Institute of Standards of Science). The result as follows The latency and amplitude of SQUID MEG responses at the human auditory cortex changed by needle-retention condition on GB43 were 7.2msec and 1.617, respectively, which were slower and larger than those of no-acupuncture condition. The amplitude of SQUID MEG responses at the human auditory cortex changed by needle-twitching condition on GB43 was 13.517, which was larger than that of no-acupuncture condition. The change in SP1 following GB43 needle-twitching condition were not observed in latency. The amplitude changed by needle-twitching condition on SP1 was 12.2fT, which was not significant. These results suggested that auditory cortex can be affected by acupuncture stimulus, though not specific or significant because of small number of subjects.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.383-388
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• 1994

Chaotic analysis of EEG signal responding to auditory stimulus with various carrier frequency and constant triggering frequency is given in this paper. The EEG signal is obtained from the digital 12channel EEG system made in our laboratory. The carrier frequency is varied from 1 kHz to 3 kHz by 0.5 kHz step. Chaos analysis such as pseudo phase space portrait, Lyapunov exponent, and so on is done on the auditory stimulated evoked potential. This result is found to be quite consistent with the well known results from the psychological perception theory.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.237-244
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• 1994

We investigated the qualitive and quantitative properties in EEG signal which responds to auditory stimulus with increaing the sound-cutting frequency from 2 Hz to 20 Hz by 2 Hz step units, by chaotic dynamics. To bigin with, general chaotic properties such as fractal mechanism, 1 If frequency spectrum and positive Lyapunov exponent are discussed in EEG signal. For evoked potential with given auditory stimulus, the route to chaos by bifurcation diagram and the changes in geometrical property of Poincare sections of 2-dimensional psedophase space is observed. For that containing spontaneous potential, seen as the random background signal, the chaotic attractors in 3-dimensional phase space are found containing the same infomation as the above mentioned evoked potential. Finally the chinges of Lyapunov exponent by various sound-cutting frequencies of stimulus and by the various spatial positions (occipital region) in a brain surface to be measured, are illustrated meaningfully.