The objective of this study was to assess the integrity of the vagal nerve afferent pathways in patients with gastroesophageal reflux disease (GERD). Seven GERD patients (4 males and 3 females, mean age 39 +/- 8 years) were studied. Twelve healthy volunteers (11 males and 1 female, mean age 32 +/- 8 years) were used as the control group. Cortical evoked potentials were measured. Electrical stimulation of the esophageal mucosa was performed through a custom-built device. Latencies and N2/P2 amplitude were measured. Reproducible cortical evoked potentials were obtained from all subjects. The stimulation threshold for GERD patients to electrical esophageal stimulation was 5.1 +/- 1.5 mA compared to 7.8 +/- 2.0 mA in healthy volunteers (p <0.05). There was no difference in peak latencies or N2/P2 amplitude between GERD patients and controls. GERD patients have a normal vagal nerve function, but they exhibit a decreased threshold for esophageal perception. The mechanism responsible for increased esophageal sensitivity observed in GERD patients is still undetermined and warrants further study.