• Title/Summary/Keyword: Amplitude and Latency

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Electrophysiologic Pattern of Facial Muscles in Bell's Palsy (얼굴마비에서 얼굴근육의 전기생리학적 양상)

  • Lee, Sang-Soo;Shin, Dong-Ick
    • Annals of Clinical Neurophysiology
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    • v.6 no.2
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    • pp.75-79
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    • 2004
  • Backgrounds: Electrodiagnostic tests have been developed to estimate the degree of facial nerve injury during the acute phase. Side-to-side amplitude comparison with the affected side expressed as a percentage of the nonaffected side has been one of the most valuable electrophysiologic methods of assessing facial nerve functioning. This study was designed to know whether there is any difference in the side-to-side comparison of amplitudes and terminal latencies of the compound muscle action potentials (CMAP) of the facial muscles in the patients with Bell's palsy. Methods: Electroneurographic recordings with surface electrodes on the frontalis, orbicularis oculi, nasalis, and orbicularis oris muscles were made within 2 weeks post-onset (mean, day 7) in 39 patients. Results: Of the 39 Bell's palsy patients, 38 patients (97.4%) recovered satisfactorily within 6 months. The amplitude of CMAP in all patients was not reduced to 10% or less of that of the contralateral healthy muscle. The correlation of amplitude change between four facial muscles was relatively strong, but the correlation of latency change was weak. When the electroneurographic values were compared in the four muscle groups, the general linear models procedure did not show any significant difference for CMAP amplitude and latency changes (p=0.62-0.63). Conclusions: This study did not show any significant clinical advantage of electroneurographic recordings in more than one facial muscle at the early stage of Bell's palsy.

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AN EXPERIMENTAL STUDY OF ELECTROPHYSIOLOGICAL AND HISTOLOGICAL ASSESSMENT ON THE INJURY TYPES IN RABBIT INFERIOR ALVEOLAR NERVE (가토의 하치조 신경 손상 형태에 따른 전기생리학적 및 조직학적 변화에 관한 실험적 연구)

  • Lee, Jae-Eun;Lee, Dong-Keun
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.18 no.4
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    • pp.679-700
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    • 1996
  • Inferior alveolar nerve dysfunction may be the result of trauma, disease, or iatrogenic injury. Inferior alveolar nerve injury is inherent risk in endodontic therapy, orthognathic surgery of the mandible, and extraction of mandibular teeth, particularly the third molars. The sensory disturbances of inferior alveolar nerve associated with such injury have been well documented clinical problem that is commonly evaluated by several clinical sensory test including Tinels sign, Von Frey test(static light touch detection), directional discrimination, two-point discrimination, pin pressure nociceptive discrimination, and thermal test. These methods used to detect and assess inferior alveolar nerve injury have been subjective in nature, relying on the cooperation of the patients. In addition, many of these techniques are sensitive to differences in the examiners experience and skill with the particular technique. Data obtained at different times or by different examiners are therefore difficult to compare. Prior experimental studies have used electro diagnostic methods(sensory evoked potential) to objectively evaluate inferior alveolar nerve after nerve injury. This study was designed with inferior alveolar nerve of rabbit. Several types of injury including mind, moderate, severe compression and perforation with 19 gauze, 21 gauze needle and 6mm, 10mm traction were applied for taking the sesory evoked ppterntial. Latency and amplitude of injury rabbit inferior alveolar nerve were investigated with sensory evoked potential using unpaired t-test. The results were as follows : 1. Intensity of threshold (T1) was $128{\pm}16{\mu}A$ : latency, $0.87{\pm}0.07$ microsecond : amplitude, $0.4{\pm}0.1{\mu}V$ : conduction velocity, 23.3 m/s in sensory evoked potential of uninjured rabbit inferior alveolar nerve. 2. Rabbit inferior alveolar nerve consists of type II and III sensory nerve fiber. 3. Latency was increased and amplitude was decreased in compression injury. The more injured, the more changed in latency and amplitude. 4. Findings in perforation injury was similar to compression injury. Waveform for sensory evoked potential improved by increasing postinjured time. 5. Increasing latency was prominent in traction injury rabbit inferior alveolar nerve. 6. In microscopic histopathological findings, significant degeneration and disorganization of the internal architecture were seen in nerve facicle of severe compression and 10mm traction group. From the above findings, electrophysiological assessment(sensory evoked potential) of rabbit injured inferior alveolar nerve is reliable technique in diagnosis and prognosis of nerve injury.

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Evoked Potential Estimation using the Iterated Bispectrum and Correlation Analysis (Bispectrum 및 Correlation 을 이용한 뇌유발전위 검출)

  • Han, S.W.;Ahn, C.B.
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.12
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    • pp.113-116
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    • 1994
  • Estimation of the evoked potential using the iterated bispectrum and cross-correlation (IBC) has been tried for both simulation and real clinical data. Conventional time average (TA) method suffers from synchronization error when the latency time of the evoked potential is random, which results in poor SNR distortion in the estimation of EP waveform. Instead of EP signal average in time domain, bispectrum is used which is insensitive to time delay. The EP signal is recovered by the inverse transform of the Fourier amplitude and phase obtained from the bispectrum. The distribution of the latency time is calculated using cross-correlation between EP signal estimated by the bispectrum and the acquired signal. For the simulation. EEG noise was added to the known EP signal and the EP signal was estimated by both the conventional technique and bispectrum technique. The proposed bispectrum technique estimates EP signal more accurately than the conventional technique with respect to the maximum amplitude of a signal, full width at half maximum(FWHM). signal-to-noise-ratio, and the position of maximum peak. When applied to the real visual evoked potential(VEP) signal. bispectrum technique was able to estimate EP signal more distinctively. The distribution of the latency time may play an important role in medical diagonosis.

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Effects of Mental Practice in Conjunction with Repetitive Transcranial Magnetic Stimulation on the Upper Limbs of Sub-acute Stroke Patients

  • Ji, Sang-Goo;Kim, Myoung-Kwon;Cha, Hyun-Gyu
    • Journal of Magnetics
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    • v.19 no.4
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    • pp.353-356
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    • 2014
  • The aim of the present study was to examine whether mental practice (MP) in conjunction with repetitive transcranial magnetic stimulation (rTMS) can improve the upper limb function of sub-acute stroke patients. This study was conducted with 32 subjects who were diagnosed with hemiparesis by stroke. The experimental group consisted of 16 members upon each of whom was performed MP in conjunction with rTMS, whreas the control group consisted of 16 members upon each of whom was performed MP and sham rTMS. Both groups received traditional physical therapy for 30 minutes a day, 5 days a week, for 6 weeks; additionally, they received mental practice for 15 minutes a day. The experimental group was instructed to perform rTMS, and the control group was instructed to apply sham rTMS for 15 minutes. A motor cortex excitability analysis was performed by motor evoked potentials (MEPs), and upper limb function was evaluated by Fugl-Meyer Assessment (FMA) and the Box and Block test (BBT). Results showed that the amplitude, latency, FMA, and BBT of the experimental group and the latency, FMA, and BBT of the control group were significantly improved after the experiment (p<0.05). Significant differences were found between the groups in amplitude and latency after the experiment (p<0.05). The results showed that MP in conjunction with rTMS is more effective in improving upper limb function than MP alone.

Effect of Acupuncture at Oegwan(TE 5) on Auditory P300 (외관(外關) 자침이 Auditory P300에 미치는 영향)

  • Kim, Mi-Sun;Park, Hyun-Cheol;Yoo, Gyung;Kim, Lak-Hyung
    • Journal of Oriental Neuropsychiatry
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    • v.17 no.1
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    • pp.129-136
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    • 2006
  • Objective : Audio-evoked potential is technique used for measuring brain functions such as memory, attention, and concentration. Although a number of studies on acupuncture for pain, there are few reports on the effect of acupuncture cognitive function. Methods : Fifteen healthy volunteers with no neurological condition took part of the study. $(23.27{\pm}2.09)$. In this study, we examined the changes in auditory P300 by acupuncture stimulation to 'Oegwan' on the left hand. Auditory P300 was recorded before, during and after acupuncture. The amplitude and latency of P300 at Fz, Cz, Pz point were calculated. Results : Auditory P300 amplitude decreased during and after acupuncture, but there was no statistical significance.(P< .05) Auditory P300 latency significantly decreased during and after acupuncture.(P< .05) Conclusions : The decrease of Auditory P300 latency time suggests that acupuncture at Oegwan has some effects on the cognitive function.

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Alzheimer Disease detection and analysis using P300 componenet of ERP in Alzheimer type Dementia (사상관련전위 P300 요소를 이용한 알츠하이머형 치매의 탐지와 분석)

  • 박은혜;이영혁;임재환;김종우;황의완;김현택
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 2002.11a
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    • pp.148-152
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    • 2002
  • This study is to develop the Alzheimers disease (AD) detection and analysis system using event-related potential (ERP) of AD patients. We recorded ERP in an auditory oddball paradigm in mild AD (n=25), severe AD (n=12), age-matched normal aged controls (n=17), and young controls (n=7). The amplitude and latency of target P300 components were compared among 4 groups. The relationship between P300 measures and neuro psychological test (K-DRS) scores were evaluated by correlations. The latency of P300 was prolonged in AD and the effects were correlated with the severity of dementia. The P300 amplitude was not affected significantly in AD. Theres no difference between normal aged group and young group. These results suggest that the P300 component is specifically affected by Alzheimer type dementia.

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Unipodal 2PAM NOMA without SIC: toward Super Ultra-Low Latency 6G

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.69-81
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    • 2021
  • While the fifth generation (5G) and beyond 5G (B5G) mobile communication networks are being rolled over the globe, several world-wide companies have already started to prepare the sixth generation (6G). Such 6G mobile networks targets ultra-reliable low-latency communication (URLLC). In this paper, we challenge to reduce the inherent latency of existing non-orthogonal multiple access (NOMA) in 5G networks of massive connectivity. First, we propose the novel unipodal binary pulse amplitude modulation (2PAM) NOMA, especially without SIC, which greatly reduce the latency in existing NOMA. Then, the achievable data rates for the unipodal 2PAM NOMA are derived. It is shown that for unequal gain channels, the sum rate of the unipodal 2PAM NOMA is comparable to that of the standard 2PAM NOMA, whereas for equal gain channels, the sum rate of the unipodal 2PAM NOMA is superior to that of the standard 2PAM NOMA. In result, the unipodal 2PAM could be a promising modulation scheme for NOMA systems toward 6G.

Study of Laryngeal Evoked Electromyography Method in Rats (백서를 이용한 후두 유발 근전도 검사 방법에 대한 연구)

  • 조선희;이재연;민선식;신유리;정성민
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.11 no.2
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    • pp.178-184
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    • 2000
  • Laryngeal evoked EMG is the objective and quantitative method to measure the innervation of laryngeal muscle. If there is a mobility disorder of vocal cords, the cause and location of neural lesion co be understood by the laryngeal evoked EMG and if there is a vocal cord paralysis, the degree of recovery and the policy of treatment can be determined by it. Recently, the studies of reinnervation after recurrent laryngeal nerve injury have been actively carried out. Laryngeal evoked EMC is useful to these studies. The aim of study is to know whether noninvasive methods for stimulating the recurrent laryngeal nerve and for recording of compound action potential(CAP) using surface electrode are as useful as the invasive method using needle electrode. We obtained EMG of laryngeal muscle by various stimulating and recording methods : 1) Direct nerve stimulation by placing nerve cuff electrode made out of silastic tube and platinum wire and recording by insertion of hook wire electrode into posterior cricoarytenoid(PCA) and thyroarytenoid(TA) muscles, respectively. 2) Recording of compound action potential by surface electrode after stimulation of recurrent laryngeal nerve by the insertion of 27 gauge of needle electrode. 3) Recording of compound action potential by surface electrode after stimulating the recurrent laryngeal nerve by transcutaneous blunt rod electrode at tracheoesophageal groove. The amplitude, duration and latency of the CAP evoked by recurrent laryngeal nerve stimulation were compared among the three groups. The amplitude of CAP was smallest in the group recorded from posterior cricoarytenoid and hyroarytenoid muscle, and that recorded by surface electrode after stimulation by needle electrode was largest. The difference in amplitude between the group by hook wire recording and the two groups by surface electrode recording was significant statistically. There is no significant difference in duration and latency among three groups. Since the waveform of CAP from all three methods has similar duration, latency, we concluded that noninvasive method is a useful as invasive methods.

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A Study of Visual Event-Related Potential P300 in Schizophrenia (정신분열병의 시각자극 사건유발전위 P300에 대한 연구)

  • Oh, Dong-Hoon;Nam, Jung-Hyun;Ahn, Dong-Hyun;Kim, Seok-Hyun;Choi, Joon-Ho
    • Korean Journal of Biological Psychiatry
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    • v.11 no.1
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    • pp.40-48
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    • 2004
  • Objective:Event-related potentials(ERPs) are electrical changes recorded at the surface of the scalp in response to stimulus presentation, and their latency and amplitude change according to cognitive processes. Through past studies of the auditory ERP in schizophrenia, the P300 has been reported to be statistically smaller and delayed in schizophrenia than comparison groups. However, studies of the visual ERP have not been systematically examined. The present study was designed to investigate the visual P300 in patients with schizophrenia and normal controls and to compare the pattern of P300 between them. Methods:The subjects were composed of patients(N=22) with schizophrenia by DSM-IV and normal controls(N=22). The visual ERPs were measured by the visual continuous performance test. P300 amplitude and latency measured on 5 scalp electrodes(Fz, Cz, Pz, $T_7$, $T_8$) were compared between patients and controls. Results:The P300 latencies measured on Fz, Cz, Pz, and $T_7$ electrodes were significantly longer in patients than controls(p<0.05). The P300 amplitudes in patients were smaller than controls. However, the difference between them was not statistically significant. Conclusion:Analysis of the visual ERPs showed that the P300 latency is significantly delayed and the P300 amplitude is slightly smaller in patients than controls. These results are similar to established studies of the auditory P300 in schizophrenia.

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A Study on the Auditory ERP measured in Sasang Constitutionally classified Three Groups (사상체질별 사건관련전위(ERP) 측정 연구 -청각 자극을 중심으로-)

  • Kim, Jeong-Ho;Song, Jeong-Mo;Kim, Lak-Hyung
    • Journal of Sasang Constitutional Medicine
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    • v.16 no.2
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    • pp.65-70
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    • 2004
  • 1. Objectives This study is to find the difference of ERP in Sasang Constitutional groups 2. Methods Auditory ERP were measured in 32 healthy males. Latency and amplitude of P300 component were analysed. 3. Results The latency of ERP P300 component in Taeumin group was more extended than that in other groups. It was significant statistically. The Amplitude of ERP P300 component in Soyahgin group was more extended than that in other groups. 4. Conclusions This results suggest that ERP measuring could be used in Sasang Constitutional diagnosis.

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