Associations among neurophysiology measures in irritable bowel syndrome (IBS) and their relevance for IBS symptoms

Abstract

Abnormal gut-brain interactions are common in irritable bowel syndrome (iBS), but the associations between neurophysiological measures and their relation to gastrointestinal (Gi) symptoms are poorly understood. Our aim was to explore these relationships and define the most relevant neurophysiology measures for Gi symptom severity in iBS. iBS patients underwent small intestinal motility (manometry; fasted and fed contraction frequency, phase III time) and secretion (transmural potential difference), rectal sensorimotor (barostat; sensory thresholds, tone response, compliance), autonomic nervous system (baroreceptor sensitivity and effectiveness), and colonic motor function (transit time) examinations. Gi symptom severity (GSRS-iBS), and anxiety and depression (HAD) as a proxy measure of central nervous system (CNS) dysfunction, were assessed. In total 281 IBS patients (Rome II criteria) were included (74% females, median age 36 [interquartile range 28-50] years). Significant correlations between neurophysiology measures were stronger within, rather than between, different neurophysiological examinations. the strongest neurophysiology-symptom correlations occurred between a combination of cnS and visceral sensitivity parameters, and GSRS-iBS total score and pain domain (ρ = 0.40, p < 0.001, and ρ = 0.38, p < 0.001). Associations between GI symptoms in IBS and individual and combinations of neurophysiological factors occurred, primarily in cnS and visceral sensitivity measures, providing new insights into the clinical presentation of iBS. Irritable bowel syndrome (IBS) is a common and complex functional gastrointestinal (GI) disorder where gut-brain interactions 1,2 , and alterations in the gut microenvironment 3 are considered to be central in the pathophysiology. Abdominal pain, related to defecation and associated with changes in stool form or frequency, are the characteristic clinical features of this female predominant disease 1 with 5-10% prevalence worldwide 4-6. The disease leads to high costs for society, due to increased use of health care services 7 , as well as lowered work productivity and higher absenteeism from work 8,9. Different abnormalities involved in gut-brain interactions are present in IBS, leading to a complex clinical presentation, but to date the pathophysiology is not completely understood. Various pathophysiological factors have been brought forward as important for symptom generation in IBS, but none of these is present in all patients with IBS. IBS patients have been reported to have increased psychological distress 10,11 , visceral hypersensitivity 12 , altered colonic motility 13 , aberrant autonomic nervous system (ANS) function 14,15 , rectal sensorimotor dysfunction 16,17 , and dysfunction of motility 18-20 and secretion 21 of the small intestine, in comparison with healthy controls. Although these abnormalities have been described individually in IBS, the associations among these aberrant measures, and the interactions between these parameters and the patient reported IBS symptom ...

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