Acute effect of caffeine on pattern-reversal visual evoked potential: a randomized-controlled study.

This study was aimed to investigate the acute effect of caffeine intake on pattern-reversal (PR) visual evoked potential (VEP). This randomized controlled study included 40 participants who were divided into two groups randomly (group 1 [study group,  = 20] and group 2 [control group,  = 20]). While the study group received coffee beverages made from 6 g pure coffee beans (36 mg of caffeine per gram) containing approximately 216 mg caffeine, the control group was given beverages containing 200 mg lactose without caffeine. PR-VEP test was performed at baseline and 1 h after the beverage intake. The right eyes of both groups were used for the statistical analysis. The median age of group 1 (8 male and 12 female) and group 2 (7 male and 13 female) were 31.0 (range, 21-59) and 36.5 (range, 20-59) years, respectively. No statistically significant difference was found between two groups in terms of age ( = 0.398) and gender ( = 0.744). Before the caffeine intake, median P100 latency and amplitudes were 109.90 ms (range: 99.60-120.60) and 12.45 µV (range: 5.20-19.30), respectively. One hour after caffeine intake, corresponding values were 110.70 ms (range: 99.00-114.60) and 12.45 µV (range: 5.70-20.0). Baseline P100 latency and amplitude values were not significantly different from the values recorded 1 h after caffeine intake ( > 0.05). This study showed that ingesting moderate amounts of caffeine did not affect PR-VEP parameters. Therefore, caffeine restriction does not seem to be required before the PR-VEP test. Further studies are needed to confirm our findings.