• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1992년도 춘계학술대회
• /
• pp.203-208
• /
• 1992

In order to restore the gait function by functional electrical stimulation(FES) in hemiplegic patients, an electrical stimulator and foot sensor were developed on the basis of optimal parameters which resulted from animal experiments. Physical properties of the soleus muscle were quite different from those of themedial gastrocnemius muscle, that is, the former had a characteristic or slow muscle and the letter had a characteristic of fast muscle in rats. Optimal parameters for electrical stimulation were 0.2ms of pulse width and 20Hz of frequency in the soleus muscle and 0.3ms, 40Hz in the medial gastrocnemius muscle. Amplitude modulated electrical stimulator with -15V of maximal output was made and automatic on-off time if the stimulator was 5 seconds. The foot sensor composed of 3 sensors in 3 pressure points of the foot was made in order to control the gai t function by closed loop feedback system. The gait function was improved by using the stimulator and foot sensor in peroneal palsy. These results suggest that the electrical stimulator with closed loop feedback system may restore the gait function in hemiplegic patients.

• 대한의용생체공학회:의공학회지
• /
• 제15권4호
• /
• pp.429-438
• /
• 1994

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate eleclromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocnemius m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher'stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical slimulator restored partially gait function in paraplegic patients.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 추계학술대회 논문집
• /
• pp.645-646
• /
• 2010

• 재활복지공학회논문지
• /
• 제10권1호
• /
• pp.59-64
• /
• 2016

본 연구에서는 기능적 전기 자극에 필요한 전기 자극 파형(Wave Form)과 Therapy, Burst, Pulse 각 구간에 필요한 전기 자극 시간과 같은 매개변수를 그래프 형식으로 시뮬레이션하고, 환자에게 전달되는 전기 에너지를 계산할 수 있도록 하는 기능적 전기 자극 시뮬레이션 응용프로그램을 개발하였으며, 개발된 시뮬레이션 응용프로그램과 전기 자극 장비에서 출력되는 전기 자극을 오실로스코프를 통해 비교 검증하였다. 응용프로그램에서 시뮬레이션 한 프로그램의 콘텐츠를 활용하기 위하여 XML 스키마를 개발하였다. 그리고 각각의 설정 값들에 대해 표준화된 코드를 이용하고 OID를 이용하여 각각의 표준화 코드들을 식별 할 수 있도록 함으로써 의료전문가들 사이에서 기능적 전기 자극 프로그램에 대한 콘텐츠 공유의 도구로 활용할 수 있도록 하였다.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제14권5호
• /
• pp.658-665
• /
• 2014

The neural stimulators have been employed to the visual prostheses system based on the functional electrical stimulation (FES). Due to the size limitation of the implantable device, the smaller area of the unit current driver pixel is highly desired for higher resolution current stimulation system. This paper presents a 16-channel compact current-mode neural stimulator IC with digital to analog converter (DAC) sharing scheme for artificial retinal prostheses. The individual pixel circuits in the stimulator IC share a single 6 bit DAC using the sample-and-hold scheme. The DAC sharing scheme enables the simultaneous stimulation on multiple active pixels with a single DAC while maintaining small size and low power. The layout size of the stimulator circuit with the DAC sharing scheme is reduced to be 51.98 %, compared to the conventional scheme. The stimulator IC is designed using standard $0.18{\mu}m$ 1P6M process. The chip size except the I/O cells is $437{\mu}m{\times}501{\mu}m$.

• 한국정보통신학회논문지
• /
• 제7권4호
• /
• pp.819-825
• /
• 2003

본 논문은 전신마비환자를 위한 FES(Functional Electrical Stimulator) 시스템 모드 변환 중의 하나를 선택할 수 있게 하는 화자 인식 시스템을 개발하고자 한다. 교통사고나 산업재해로 인한 마비환자가 늘어나고 있는 현대사회에서 환자의 운동 보조를 위해서 또는 운동 능력의 회복을 위하여 FES 시스템에 대한 연구가 늘어나고 있다. FES의 동작은 휴지, 운동, 치료 등 몇 개의 모드를 선택해야 하는데, 사지마비환자의 경우에는 키패드 조작이 불가능하므로 가장 일반적이고 자연스러운 언어로 이들 모드를 선택하고자 한다. 화자 인식 소자로는 Sensory(주)의 RSC-300을 사용하였고, FES 시스템과 RSC-300의 인터페이스는 PIC16F84마이크로 콘트롤러를 사용하였다.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1996년도 추계학술대회
• /
• pp.99-102
• /
• 1996

The ultimate object of FES is on the recovering function of body and shape demaged from desease or injury to original state. On this study, object is recovering of gait function of the disabled who, especially, have gait disturbance. Paralyzed muscle from the central nerve disable, if peripheral nerves which be in the lower part of the harmed are activated, muscle contraction is possible. The traumatic trouble, peripheral nerves aren't connected to a central nerve but origin of peripheral nerve cells which are in the lower part of the harmed are alive, react on stimulation. We design 4-channel stimulator, being based on standard stimuli pattern. stimulator is manufactured with compact size and light weight to portable.

• 한방재활의학과학회지
• /
• 제18권1호
• /
• pp.111-123
• /
• 2008

Objectives : The objective of this study was to investigate the outcomes of functional electrical stimulation (FES) which was applied twice a day in patients with dysphagia after stroke. Methods : Eleven patients with dysphagia after stroke were participated. The electrical stimulator with two channels was employed for forty minutes daily or forty minutes twice a day for fifteen days. Participants were divided into two groups by random method; The FES was performed twice a day for Twice-FES group (n=6), and once a day for Standard-FES group (n=5). For evaluation of dysphagia, the functional dysphagia scale by videofluoroscopic swallowing study, and swallow function scoring system by six clinical swallowing stage were assessed at pre- and post-treatment. Results : In both groups, there was a significant decrease of total functional dysphagia scales after FES treatment (p<0.05) and the results mainly affected the pharyngeal phase of deglutition. There was no significant difference between the two groups in total functional dysphagia scales, but the Twice-FES group had a decreased residue in oral cavity compared to the standard FES group. In both groups, there were significant improvements in swallow function scoring system (p<0.05). The twice-FES group had more high clinical swallowing stages. Conclusions : The results demonstrated that FES is a clinically effective intervention in treatment of stroke patients with dysphagia. Moreover, the treatment applied twice a day had relatively positive effects on the reduction of oral cavity residue and the improvement of clinical swallowing stage.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제52권12호
• /
• pp.708-716
• /
• 2003

The surface EMG signal detected from voluntarily activated muscles can be used as a control signal for functional electrical stimulation. To use the voluntary EMG signal, it is necessary to eliminate the muscle response evoked by the electrical stimulation and enable to process the algorithm in real time. In this paper, we propose the Gram-Schmidt(GS) algorithm and implement it in FPGA(field programmable gate array). GS algorithm is efficient to eliminate periodic signals like muscle response, and is more stable and suitable to FPGA implementations than the conventional least-square approach, due to the systolic array structure.

• 대한의용생체공학회:의공학회지
• /
• 제24권6호
• /
• pp.523-531
• /
• 2003

본 연구에서는 표면 전극을 사용하는 8채널 전기자극 시스템을 개발하였고. 이 시스템을 이용하여 하반신 마비한자의 근력강화를 위한 전기자극 엑서사이즈와 FES 보행을 하였다. 본 연구에서 개발한 전기자극 시스템은 컴퓨터 프로그램, 전기자극기, 그리고 컴퓨터 프로그램과 전기자극기를 연결하는 통신부분으로 구성되어 있다. 컴퓨터 프로그램에서는 마우스를 이용하여 임의의 자극 패턴을 손쉽게 구성하고 편집학 수 있으며 이렇게 구성/편집된 자극 패턴은 동원곡선(recruitment curve)을 통하여 자극 파라미터로 변환된다. 자극 파라미터는 직렬통신을 이용하여 전기자극기에 전달된다. 전기자극기는 주제어부에 1개, 각 채널에 1개씩 총 9개의 마이크로프로세서로 구성되어 있다. 주제어부의 마이크로프로세서가 컴퓨터 프로그램과 통신을 하고 각 채널의 마이크로프로세서를 제어한다. 본 연구에서 개발한 기능적 전기자극 시스템으로 하반신 마비환자에게 100주 동안 전기자극 엑서사이즈를 실시한 결과 근력, 다리둘레, 그리고 피로저항성의 증가를 볼 수 있었다. 전기자극 엑서사이즈로 무릎신근(knee extensor muscle)이 체중을 지지한 수 있을 정도로 증가한 후에 FES 보행을 시작하였고, 현재 2분 동안 50m 이상 보행할 수 있다.