Authors : Parthasarathi Roy, Shreoshee Ghosh
DOI : 10.18231/j.ijceo.2023.004
Volume : 9
Issue : 1
Year : 2023
Page No : 19-24
Aims: To establish normative database and investigate whether VEP amplitude and latency have any correlation between them.
Methods: 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.
Results: 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.
Conclusions: PVEP amplitude and latency are uncorrelated variables. To the best of our knowledge, our study was the first study in the literature on correlation between the amplitude and latency of PVEP.
Keywords: Pattern visual evoked potential, N75-P100 amplitude, P100 latency, Correlation