Normative values of visual evoked potentials in Northeastern of Iran

Abstract

Purpose Visual evoked potentials (VEPs) provide important diagnostic information related to the functional integrity of the visual pathways. The aim of this study was to establish normative values of different components of pattern reversal VEPs on Iranian normal adult subjects. Methods Monocular and binocular pattern reversal VEPs were recorded on 59 healthy participants (22.55 ± 3.79 years old) using the Roland RETI system for two check sizes of 15 and 60 min of arc. The measured VEP components were the latencies of N75, P100, N135 and amplitude of N75–P100. Results Repeated measures ANOVA showed that viewing eye condition has a significant impact on the amplitude of N75–P100 ( P < 0.001, F = 13.89). Also, the effect of check size on the latencies of N75, P100, N135, amplitude of N75–P100 ( P ≤ 0.010), as well as the intraocular difference of P100 latency and amplitude N75–P100 ( P = 0.007) was significant. More specifically, the amplitude of N75–P100 in both check sizes significantly differed between gender groups ( P < 0.023). Conclusion According to the results of this study, VEPs components are affected by the stimulus size, monocular and binocular recording conditions and gender. Therefore, it is necessary to determine the normative values of VEPs in each population, so that the results could be used in clinical studies.

Comparison of CRT and LCD monitors for objective estimation of visual acuity using the sweep VEP

“…The mean peak-to-trough amplitude using the LCD monitor in the first experiment is reduced by about 0.9 µV with a confidence interval from − 1.6 to − 0.2 µV compared to the CRT stimulator, but increased by about 2.6 µV (confidence interval from 1.2 to 4.0 µV) when comparing the new LCD monitor with the CRT monitor (both with high contrast) in the second experiment (Table 5 ). However, these differences were, despite being statistically significant, within the expected standard deviation from about 0.5 to 7 µV of the P100 amplitude found in the literature [ 29 – 31 ] and therefore probably of no clinical relevance (Fig. 2 , right).…”

Long‐term effects of methamphetamine abuse on visual evoked potentials

“…Among pattern-reversal VEP parameters, the P100 peak time exhibits very low variability between subjects and is highly sensitive to the integrity of neural pathways. 18,22 Therefore, a possible reason for the increased P100 peak time in methamphetamine users could be the alteration of early cortical processing in the primary visual area (V1/V2) or subclinical retinal changes. Our subjects all had BCVA <0.2 LogMAR and those with retinal diseases were excluded.…”

“…Besides, decreased VEP amplitude has been observed in moderate-to-severe users of ecstasy drugs, which are derivatives of amphetamine and have a similar structure to methamphetamine. 16,18,19 Given the increasing illicit use of synthetic drugs such as methamphetamine and crystal methamphetamine, as well as their disputed role in vascular changes and ischaemia within the retina and optic nerve, 20 the present study was designed to compare VEP components in normal individuals and long-term users of methamphetamine and crystal methamphetamine.…”

Görsel Uyandırılmış Potansiyellerin Normal Verilerinin Değerlendirilmesi: Bir Elektronörofizyoloji Laboratuvarının Deneyimi

“…Amplitüdler değerlendirildiğinde ise bazı çalışmalarda kadınlarda daha yüksek bulunmuştur. [5][6][7][8][9] Kadınlarda yüksek amplitüd nedeni olarak da küçük kafatası ve endokrin faktörlerin olası neden olabileceği belirtilmiştir. 6 Bulut ve ark.…”

“…10 Amplitüdler kadınlarda büyük saptandığı gibi küçük olduğunu bildirir çalışmalar da vardır. [9][10] Biz çalışmamızda bu literatürlerden farklı olarak amplitüdler arasında anlamlı fark saptamadık.…”