• 제목/요약/키워드: Visual Stimulation

검색결과 360건 처리시간 0.028초

안정상태 시각유발전위 기반의 기능적 전기자극 재활훈련 시스템 (Steady-State Visual Evoked Potential (SSVEP)-based Rehabilitation Training System with Functional Electrical Stimulation)

  • 손량희;손종상;황한정;임창환;김영호
    • 대한의용생체공학회:의공학회지
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    • 제31권5호
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    • pp.359-364
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    • 2010
  • The purpose of the brain-computer (machine) interface (BCI or BMI) is to provide a method for people with damaged sensory and motor functions to use their brain to control artificial devices and restore lost ability via the devices. Functional electrical stimulation (FES) is a method of applying low level electrical currents to the body to restore or to improve motor function. The purpose of this study was to develop a SSVEP-based BCI rehabilitation training system with FES for spinal cord injured individuals. Six electrodes were attached on the subjects' scalp ($PO_Z$, $PO_3$, $PO_4$, $O_z$, $O_1$ and $O_2$) according to the extended international 10-20 system, and reference electrodes placed at A1 and A2. EEG signals were recorded at the sampling rate of 256Hz with 10-bit resolution using a BIOPAC system. Fast Fourier transform(FFT) based spectrum estimation method was applied to control the rehabilitation system. FES control signals were digitized and transferred from PC to the microcontroller using Bluetooth communication. This study showed that a rehabilitation training system based on BCI technique could make successfully muscle movements, inducing electrical stimulation of forearm muscles in healthy volunteers.

Psychophysiological Reactivity to Affective Visual Stimulation of Negative Emotional Valence: Comparative Analysis of Autonomic and Frontal EEG Responses to the IAPS and the KAPS

  • Sohn, Jin-Hun;Estate M. Sokhadze;Lee, Kyung-Hwa
    • 감성과학
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    • 제3권2호
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    • pp.29-40
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    • 2000
  • Autonomic and EEG responses were analyzed in 32 college students exposed to visual stimulation with Korean Affective Picture System (KAPS) and 36 students exposed to the International Affective Picture System (IAPS). Cardiac, electrodermal, and electrocortical measures were recorded during 30 sec of viewing affective pictures. The slides intended to elicit basic emotions (fear, anger, surprise, disgust, and sadness) were presented to subjects via Kodak slide-projector. The aim of the study was to differentiate autonomic and EEG responses associated with the same negative valence emotions elicited by KAPS and IAPS stimulation and to identify the influence of cultural relevance on physiological reactivity. The analysis of obtained results revealed significant differences in physiological responsiveness to emotionally negative valence slides from KAPS and IAPS. The typical response profile for all emotions elicited by the KAPS included HR acceleration (except surprise), and increase of electrodermal activity, slow and fast alpha blocking and fast beta power increase in EEG, which was not associated with significant asymmetry (except fast alpha in sadness). Stimulation with the IAPS evoked HR deceleration, specific electrodermal responses with relatively high tonic electrodermal activation, alpha-blocking and fast beta increase, and was accompanied also by theta power increase and marked frontal asymmetry (e.g., fast beta, theta asymmetries in sadness, fast alpha in fear). Physiological responses to fear and anger-eliciting slides from the IAPS were significantly less profound and were accompanied by autonomic and EEG changes more typical for attention rather than negative affect. Higher cardiovascular and electrodermal reactivity to fear emotion observed in the KAPS, e.g., as compared to data with the IAPS as stimuli, can be explained by cultural relevance and higher effectiveness of the KAPS in producing certain emotions such as fear in Koreans.

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피부자극이 혈액투석환자의 동정맥루 천자시 동통감소에 미치는 영향 (The Efect of Cutaneus Stimulation on AV Fistula Puncture Pain of Hemodialysis Patients)

  • 박정숙
    • 대한간호
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    • 제33권1호
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    • pp.37-51
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    • 1994
  • The cutaneous stimulation is an independent nursing intervention used in various painful conditions, and is explained by gate control theory. This study was aimed at identifying the effect of cutaneous stimulation on reduction of arteriovenous fistula puncture pain of hemodialysis patients. One group repeated measurement post test research was designed. Forty-five hemodialysis patients who received arteriovenous fistula puncture regulary in hemodialysis units of an attacted D hospital to K university have been studied from August 16 to 21, 1993. First the arteriovenous fistula puncture pain of control period was measured, and then the arteriovenous fistula puncture pain of experimental period(with cutaneous stimulation) was measured. The instrument used for this study were visual analogue pain scale as subjective pain measurement, objective pain behavior checklist and Spielberger's Trait Anxiety Inventory as intervening variables. Analysis of data was done by use of paired t-test, t-test, ANOVA and Perarson correlation coefficient. The results of this study were summarized as follows; 1) The first hypothesis that the subjective pain score of arteriovenous fistula puncture pain in experimental period(with cutaneous stimulation) will be lower than in control period was partly supported. The subjective pain score of arterial line was rejected(paired t=-0.28, p=0.77) and the subjective pain score of venous line was supported(paired t=2.61, p=0.01). 2) The second hypothesis that the objective pain behavior score of arteriovenous fistula pain in experimental period(with cutaneous stimulation) will be lower than in control period was rejected(arterial line paired t=-0.45, p=0.65; venous line paired t=-0.36, p=0.72). 3) The third hypothesis that the cardiopulmonary signs of arteriovenous fistula puncture pain in experimental period(with cutaneous stimulation) will be lower than in control period was rejected(pulse paired t=-0.8, p=0.42; systolic BP paired t=0.98, p=0.33; diastolic BP paired t=0.43, p=0.66). Further experimental studies with simple intravenous injection patients will be recommended in order to identify the effect of cutaneous stimulation.

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시청각자극 후의 피험자의 자의적 반응시간의 자동계측과 유발뇌파분석을 위한 동기신호의 생성 (Automatic measurement of voluntary reaction time after audio-visual stimulation and generation of synchronization signals for the analysis of evoked EEG)

  • 김철승;엄광문;손진훈
    • 감성과학
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    • 제6권4호
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    • pp.15-23
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    • 2003
  • 근래에 들어 질병으로 인하여 의사표현이 곤란한 환자에게 뇌파에 기초한 BCI(Brain Compute, Interface)와 같은 새로운 인터페이스를 제공하고자 하는 연구가 활발히 진행되고 있다. 특정 자극에 대해 유발되는 뇌파의 측정과 분석은 BCI를 위한 뇌파의 패턴과 인터페이스의 설계에 중요한 역할을 한다. 이 연구의 목적은 시청각 자극 인가 후 피험자의 반응시간을 측정하는 시스템을 EEG와 같은 생체 신호 계측 시스템과 연동이 가능한 형태로 개발하는 것이다. 제안된 시스템은 기능적으로 자극신호 발생부, 반응시간 측정부, 유발뇌파 측정부, 동기신호 발생부로 나뉘어진다. 자극신호 발생부는 실험에 이용되는 자극신호를 제작하는 부분으로서 Flash를 사용하여 구현하였다. 반응시간 측정부는 문제에 대한 답 선택 요청시각으로부터 피험자의 반응까지의 시간을 측정하는 부분으로서 마이크로컴퓨터를 이용하여 구현하였다. 유발뇌파 측정부는 시판용 하드웨어와 소프트웨어를 그대로 사용하였다. 동기신호 발생부는 전체 시스템의 동기를 맞추기 위한 신호를 발생하는 부분으로서 문제제시, 답 요구와 동기한 화면상의 명암신호와 이를 검출하는 광센서로 구성하였다. 본 논문에서 제시한 방법에서는, 기존의 유발전위 측정 및 자극시스템에 특정 모듈(반응시간 측정 장치, 동기신호 발생장치)만을 추가하여 실험자의 의도에 맞는 시스템을 설계할 수 있어 유발응답 및 반응시간의 측정을 필요로 하는 연구를 가속화 할 것이 기대된다.

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A Multi-photodiode Array-based Retinal Implant IC with On/off Stimulation Strategy to Improve Spatial Resolution

  • Park, Jeong Hoan;Shim, Shinyong;Jeong, Joonsoo;Kim, Sung June
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제17권1호
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    • pp.35-41
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    • 2017
  • We propose a novel multi-photodiode array (MPDA) based retinal implant IC with on/off stimulation strategy for a visual prosthesis with improved spatial resolution. An active pixel sensor combined with a comparator enables generation of biphasic current pulses when light intensity meets a threshold condition. The threshold is tuned by changing the discharging time of the active pixel sensor for various light intensity environments. A prototype of the 30-channel retinal implant IC was fabricated with a unit pixel area of $0.021mm^2$, and the stimulus level up to $354{\mu}A$ was measured with the threshold ranging from 400 lx to 13120 lx.

음악과 색채조명 자극에 의한 HRV 스펙트럼의 변화에 관한 연구 (Evaluation of HRV spectrum variation to Color light and Music stimulation)

  • 김지훈;정동실;손기호;김남균
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1998년도 추계학술대회
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    • pp.137-138
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    • 1998
  • The purpose of this study is to evaluate the HRV(Heart Rate Variability) to visual and auditory stimulation. We analysed psychological effect and HRV of music, light, and music with light. The results show that HRV pattern is significantly related to the psychological effect, and HRV spectrum is useful to extract more information when various stimulation are presented.

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실내공간에서 자연요소의 지각이 심리적 건강에 미치는 영향 (Effects of Perceiving Natural Environments on Psychological Health in Interior Space)

  • 김남길
    • 한국실내디자인학회논문집
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    • 제27호
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    • pp.57-63
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    • 2001
  • It is believed that visual exposure to nature in the interior environment can make human healthier. But little about the effect of visual environment on human health is known. This article employs some existing evidences that perceptual experience of natural elements in the interior environment could reduce mental fatigue. The results of this article are shown as follows: First, the perception of natural elements is a physiological activity in terms of psychological health. Secondly, the visual stimulation of nature provoking proper arouse helps psychological balance. The aim of this article is to provoke further thinking and research on this possibility that visual exposure to nature may make people healthier.

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시각적 부조화를 통한 로버트 벤추리 건축과 팝아트의 방법적 유사성에 관한 연구(1) (A Study about the Methodological Similarity of Robert Venturi's Works and American Pop Art in the Light of Visual Dissonance(1))

  • 신유림;임석재
    • 건축역사연구
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    • 제21권4호
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    • pp.59-70
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    • 2012
  • This study aims to find methodical similarities between pop art and Robert Venturi's works. Pop art and Robert Venturi's works gave attention to periodical changes and wanted to communicate with the public. This study approaches a topic from psychological viewpoints, especially visual dissonance. The results are as follows: 1. Manufactured Products ; Commercial Ornaments ${\rightarrow}$ Character Changes in Experienced Stimulation 2. Daily Elements ; Traditional Elements(Classic) ${\rightarrow}$ Contextual Effect of Canonic Representation In these cases, visual dissonance attracted a lot of public attention, and people would develop new meanings of objet. Pop art and Robert Venturi's works indicated value change in post-industrial society, therefore, this study can help to understand the correlation.

The Effects of Somatosensory Stimulation of the Hands on the Hand Functions and Visuomotor Coordination Function of Children with Developmental Disabilities

  • Kong, Nam Ho;Lee, Jun Cheol;Lee, Han Ki
    • 국제물리치료학회지
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    • 제5권1호
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    • pp.652-660
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    • 2014
  • In the present study, to examine the effects of somatosensory stimulation of the hands on the hand functions and visuomotor coordination of children with developmental disabilities, a total of 24 sessions of experiments were conducted with three children with developmental disabilities for 60 minutes per session, three sessions per week from January 7, 2013 to March 11, 2013. To examine the effects of somatosensory stimulation of the hands on grasping and visuomotor coordination which are sub-areas of PDMS-2, the A-B study design was used which is a single case study method out of single-subject experimental research designs. Somatosensory stimulation of the hands was shown to be effective in improving the hand functions of children with developmental disabilities. Somatosensory stimulation of the hands showed positive effects on the raw scores and standardized scores of grasping and visuomotor coordination in all the three subject children. Visuomotor coordination functions showed higher scores in post-hoc tests in all three children. In particular, ring throws showed high scores at right $90^{\circ}$, right $45^{\circ}$, center, left $45^{\circ}$, and left $90^{\circ}$ among visual directions. In the present study conducted with children with developmental disabilities, ring throws were performed to examine visuomotor coordination. In particular, the numbers of successes of ring throws on the front, left, and right were shown to be high. Therefore, somatosensory stimulation of the hands was effective on the hand functions and visuomotor coordination functions of children with developmental disabilities.

약침 주입 용량 및 자입 방법에 따른 자극량 차이 연구 (Research on the Amount of Stimulus Differences According to Pharmacopuncture Injected dose and Characters Method)

  • 최유나;오지윤;조현석;김경호;김갑성;이승덕;김은정
    • Journal of Acupuncture Research
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    • 제32권1호
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    • pp.89-95
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    • 2015
  • Objectives : This study was designed to discover the difference in stimulation effect when the volume and insertion method of mountain ginseng pharmacopuncture was varied. Methods : 48 healthy people were randomly injected with 0.1, 0.3, 0.5, and 0.7 cc of mountain ginseng pharmacopuncture, perpendicularly or transversely at acupoints $LI_9$ and $LI_{10}$. The subjects noted their level of stimulation on a 100 mm visual analog scale(VAS) immediately after, 3 minutes after, and 5 minutes after the treatment. Results : There was no significant statistical difference in the stimulation strength between perpendicular injection and transverse injection pharmacopuncture. There was significant statistical difference in the stimulation strength when the volume of pharmacopuncture was varied. As the volume of pharmacopuncture increased from 0.1 cc to 0.3 cc, and to 0.5 cc, the stimulation strength increased as well. Conclusions : We found that volume of pharmacopuncture may be a controlling element for mountain ginseng pharmacopuncture. Additional study is needed for pharmacopuncture's stimulation adjusting factors.