Effects of esophageal stimulation in patients with functional disorders ofthe gastrointestinal tract

We studied the effects of esophageal electrical stimulation on cortical-evo ked potentials (EPs) and power spectrum of heart rate variability (PS/HRV) in patients with diabetes and noncardiac chest pain (NCCP). We also recorde d cognitive-evoked potentials (P300 EPs) in response to an odd-ball stimula tion in patients with NCCP. Diabetic patients did not yield reproducible co rtical EPs. Their power spectra of heart rate variability (PS/HRV) showed a n increased vagal modulation during stimulation. In patients with NCCP the P300 EPs were of greater amplitude (17 +/- 3 mu V vs. 12 +/- 1 mu V in cont rols, p < 0.04), while peak latenceis were slightly elongated in patients ( 382 +/- 22 ms vs. 354 +/- 12 ms in controls). The PS/HRV in these patients also showed an increased vagal modulation of the sinus node activity. Our r esults suggest the following: (1) in patients with diabetes, afferent pathw ays and processing of sensory signals are likely to be impaired; (2) an inc reased perception of esophageal stimulation reflects an exaggerated brainst em response and altered cortical processing of visceral sensation in patien ts with NCCP.