From stimulus timing to real-world clinical peak time distributions: CRT versus LCD pattern-reversal VEP

This study was conducted to ascertain how display-dependent timing differences translate into changes in pattern-reversal visual evoked potential (PR-VEP) P100 peak time distributions, using physical measurements, controlled benchmark data, and large-scale routine clinical recordings with cathode ray tube (CRT) and liquid crystal display (LCD) systems.

We analyzed PR-VEP recordings acquired before and after a routine transition from CRT to LCD systems. The study integrated three complementary data sources: photodiode measurements of trigger-to-luminance delay, a benchmark dataset of 10 healthy participants, and a retrospective clinical dataset comprising 1772 waveforms from 915 examinations. Cross-sectional peak time distributions and within-eye paired comparisons were evaluated.

Mean trigger-to-luminance delay under the LCD conditions was 13.7 ms. Corresponding prolongation of P100 peak time was observed in the benchmark dataset. In the clinical dataset, the P100 peak time distribution showed a rightward shift (mean difference 12.1 ms, 95% confidence interval 10.45-13.56 ms; Cohen's d = 0.73; p < 0.001). Quantile analysis revealed an approximately constant shift across the distribution. Within-eye longitudinal analyses confirmed that this shift also occurred at the individual level.

Display-related timing differences produce a systematic shift in PR-VEP peak time distributions. These findings demonstrate that device-dependent peak time offsets present important implications for clinical interpretation, underscoring needs for device-specific reference considerations in electrophysiological practice. Direct measurement of trigger-to-luminance delay might help estimate clinically relevant peak time shifts caused by hardware replacement.