Normative Data for Peak Latencies and Amplitudes of P100 wave of Pattern Reversal Visual Evoked Potential in Central Indian Population

Agrawal, Juhi; Pandey, Subodh; Som, Vivek

doi:10.5958/2320-608x.2019.00007.6

Cited by 2 publications

(2 citation statements)

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“…Also, difference in head circumference, 14 asymmetry of optic nerve length may cause variation in the values of amplitudes and latencies across the globe. 12 Gupta S et al (2016). 13 However our study results by and large corroborated with that of with Tandon et al (1997).…”

Section: Discussionsupporting

confidence: 88%

Amplitude and latency of visual evoked potential are un-correlated variables: A revelation from normative laboratory database of eastern India

Roy

Ghosh²

2023

IJCEO

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To establish normative database andinvestigate whether VEP amplitude and latency have any correlation between them. Institution based cross-sectional observational study done in Electrophysiology of Vision Laboratory at a tertiary centre in Eastern India. 126 subjects of age group between 20 and 59 years of either sex with best corrected visual acuity 6/6 in both eyes and no other eye ailments (except error of refraction) on examination with informed consent were included. PVEP with pattern reversal stimulus with check element size 1° (60') was recorded with Retimax “Advanced” machine (manufactured by CSO s.r.l., (Firenze) Italy) and standard silver-silver chloride disc electrodes. The test parameters were customized in the machine by the manufacturer and designated to measure the N75-P100 amplitude and P100 latency.Normative values were established for our laboratory. Only the most reliable parameters for clinically significant alterations of visual pathway i.e. N75-P100 amplitude and P100 latency were included in the analysis. Results of uniocular, age group-wise and gender-wise values were obtained by descriptive statistics as per ISCEV guidelines. No linear co-relationship (ascertained by Spearman's rho Correlation Coefficient) was found between N75-P100 amplitude and P100 latency, in either of the eyes. PVEP amplitude and latency are uncorrelated variables. To the best of our knowledge, our study was the first study in literature on correlation between amplitude and latency of PVEP.

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Section: Discussionsupporting

confidence: 88%

Amplitude and latency of visual evoked potential are un-correlated variables: A revelation from normative laboratory database of eastern India

Roy

Ghosh²

2023

IJCEO

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“…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).…”

Section: Discussionsupporting

confidence: 57%

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

et al. 2022

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Purpose To investigate the applicability of liquid crystal displays (LCD) as suitable replacement for cathode ray tube monitors (CRT) as stimulator for the sweep VEP for estimating visual acuity. Methods In a first experiment, sweep VEPs were recorded in 13 healthy volunteers with best-corrected visual acuity with an LCD and a CRT monitor, respectively. Time-to-peak after stimulus and peak-to-trough amplitudes as well as the visual acuity, estimated using a second-order polynomial and the modified Ricker model, were compared between both monitor types. In a second experiment, sweep VEPs were recorded in six healthy volunteers with two levels of stimulus contrast using artificially reduced visual acuities as well as best-corrected with the same monitors as in the first experiment and additionally, a modern LCD gaming monitor with a response time of 1 ms. Time-to-peak after stimulus and peak-to-trough amplitudes were compared between the different combinations of monitors and contrasts. Finally, visual acuities estimated using the modified Ricker model were compared to subjective visual acuities determined using the Freiburg Visual Acuity and Contrast Test (FrACT). Results In the first experiment, the time-to-peak after stimulus presentation was statistically significantly delayed for LCD displays (mean difference [confidence interval]: 60.0 [54.0, 65.9] ms; t(516) = 19.7096, p < 0.0001). Likewise, peak-to-trough amplitudes were statistically significantly smaller for the LCD stimulator, however, not clinically relevant (mean difference [confidence interval]: − 0.89 [– 1.59, − 0.20] µV; t(516) = − 2.5351, p = 0.0115). No statistically significant effect of the monitor type on the estimated visual acuity was found for neither method, second-order polynomial, nor the modified Ricker model. In the second experiment, statistically significant delays of the time-to-peak after stimulus onset were found for all combinations of monitor and contrast compared to the CRT monitor. A statistically significant, but not clinically relevant, difference of the peak-to-trough amplitudes was only found between the CRT monitor and the LCD gaming monitor (mean difference [confidence interval]: 2.6 [1.2, 4.0] µV; t(814) = 4.66, p < 0.0001). Visual acuities estimated from LCD stimulation significantly underestimated the subjective visual acuity up to 0.2 logMAR using the conversion formula of the first experiment. No statistically significant difference was found when using conversion formulas adjusted for each combination of monitor and contrast. Conclusions Based on the results of this study, LCD monitors may substitute CRT monitors for presenting the stimuli for the sweep VEP to objectively estimate visual acuity. Nevertheless, it is advisable to perform a calibration and to collect normative data of healthy volunteers using best-corrected and artificially reduced visual acuity for establishing a conversion formula between sweep VEP outcome and the subjective visual acuity before replacing a CRT with an LCD stimulator.

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Normative Data for Peak Latencies and Amplitudes of P100 wave of Pattern Reversal Visual Evoked Potential in Central Indian Population

Cited by 2 publications

References 0 publications

Amplitude and latency of visual evoked potential are un-correlated variables: A revelation from normative laboratory database of eastern India

Amplitude and latency of visual evoked potential are un-correlated variables: A revelation from normative laboratory database of eastern India

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

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