Lessons Learned from Visceral Sensory Stimulation: Implications for Treatment of Chronic Abdominal Pain

Abstract

Characterization of gut pain is fundamental in the diagnosis and assessment of organ dysfunction, leading to optimal treatment. Quantitative sensory testing (QST) provides information on sensory function at the peripheral and central level of the nervous system by recording subjects’ responses (subjective or objective) to different external stimuli. The primary advantage is that stimuli can be controlled, repeated, and modulated, and that the responses can be assessed qualitatively and quantitatively with psychophysical, neurophysiological, and imaging methods. Consequently, QST has successfully been used to characterize mechanisms underlying different pain disorders, to investigate how analgesics exert their effects on the gastrointestinal (GI) tract, and to test the effect and mechanisms of new drugs. In general, these methods have indicated that the central nervous system component of the pain system plays a major role in functional GI disorders. In organic diseases, however, the pain regulatory systems are intact, but the balance between afferent activity and local/central pain inhibition is often malfunctioning. Finally, QST has shed light over the mechanisms of analgesics and new indications in pain treatment. Finally, it has been used to tailor individualized pain therapy with the potential to stratify patients into responders and nonresponders to treatment.