Background & aims: Paying attention to the gut may magnify perception of abdominal symptoms, but the actual influence of attention by anticipatory knowledge and distraction on gut perception remains poorly defined. The aim of this study was to determine whether mental activity, attention vs. distraction, affects intestinal perception and whether mental effects are synergistic with other modulatory mechanisms.
Methods: Perception of 1-minute intestinal balloon distentions applied at 7-13-minute random intervals was measured in healthy subjects. First, distentions were tested during attention by anticipatory knowledge and during distraction (n = 8). Because somatic transcutaneous electrical nerve stimulation (TENS) reduces gut perception, distentions were then tested during attention alone, attention plus somatic TENS, and during distraction plus TENS (n = 8).
Results: Perception of intestinal distentions was higher during attention than during distraction (3.3 +/- 0.2 vs. 2.9 +/- 0.1 [mean +/- SEM]; P < 0.05). The area of somatic projection was greater during attention (P < 0.05). Intestinal compliance and oral reflex relaxation remained unchanged. During application of somatic TENS, perception of intestinal distention was higher during attention than distraction (2.4 +/- 0.3 vs. 1.7 +/- 0.2; P < 0.05). However, TENS did not alter the perception score during attention.
Conclusions: Mental activity may modulate gut perception and overrides the effects of somatic TENS on gut perception.