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J. Patel, C. Tello, P. H. Derr, C. G. V. De Moraes, E. Kim, T. S. Prata, J. M. Liebmann, R. Ritch; Repeatability of Fast Transient Visual Evoked Potentials in Normal Subjects. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5879.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the within-session repeatability of a new fast transient visual evoked potential (ftVEP) in normal individuals.
We tested 30 normal subjects (20/20 visual acuity, normal 24-2 SITA Standard VF) with ftVEP. Test duration was 20 seconds/eye. Synchronized single-channel ftVEPs were recorded using a modified Diopsys Enfant System (Diopsys, Inc., Pine Brook, New Jersey, USA), which generated a time series of 240 data points per analysis window. Two patterns were used in the study: 85% and 10% Michelson contrast. Each eye was tested 10 times (5 with 10% and 5 with 85% contrast). The following information was identified from the filtered N75-P100-N135 complex: N75 amplitude, N75 latency, P100 amplitude, P100 latency, Delta P100-N75 amplitude, and Delta P100-N75 latency. The standard deviations for the five ftVEPs for each OS, OD and OU at each contrast level were calculated. The standard deviations for OS, OD and OU were grouped into two data sets based on contrast level.
Mean age was 27.3±5.2 yrs. The total number of tests was 900 [30 patients x 3 (OD, OS, OU) x 5 (re-tests) x 2 (10% and 85%)]. The mean P100 latency at 10% and 85% contrast were 114.7 (95% CI: 113.4-116.1) and 103.7 (102.5-104.9), respectively. The table summarizes the repeatability data. The N75-P100 amplitudes were 5.1 (4.5- 5.7) and 8.0 (6.8-9.3), respectively. The inter-eye correlation was significant for both delta amplitudes and P100 latencies at 85% (r2 = 0.87 and r2=0.53, p<0.01, respectively) and at 10% (r2 = 0.48 and r2=0.41, p<0.01, respectively).
FtVEP technology showed good within-session repeatability and good inter-eye correlation.Table 1: Within session variability (standard deviation values) of ftVEP parameters
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