Objective: To determine whether a lack of symptoms in diabetic patients with gastrointestinal motility disorders is associated with visceral afferent neuropathy.
Research design and methods: We investigated cerebral evoked potentials (EPs) after esophageal stimulation in 10 patients with motor dysfunction of the gastrointestinal tract and in 10 healthy control subjects. All patients had insulin-dependent diabetes mellitus (5 men, 5 women, age range 31-60 yr, diabetes duration 8-36 yr, 10 of 10 with polyneuropathy, 6 of 10 with cardiac autonomic neuropathy). Their esophageal and gastric motor disorders had been diagnosed by scintigraphy, and gastrointestinal stenosis had been excluded by gastroscopy. Only 2 patients had severe symptoms, whereas 6 patients complained of minor discomfort (distension, bloating), and 2 patients were symptom free.
Results: EPs were recorded after electrical stimulation of the esophagus (32 cm from the incisors) at intensity just above the perception threshold. All control subjects exhibited regular EPs at 0.1 ms/30 mA stimulation intensity. In 6 diabetic patients, no EPs were detected at 0.1 and 0.3 ms/30 mA, and the perception thresholds were significantly elevated. In 4 patients with normal perception threshold, EPs of regular shape but decreased amplitude were recorded. These patients had mild or severe gastroparetic complaints.
Conclusions: These data show for the first time an association between a lack of symptoms in diabetic gastrointestinal motility disorders and visceral afferent neuropathy.