Psychological factors selectively upregulate rectal pain perception in hypersensitive patients with irritable bowel syndrome

BACKGROUND: Visceral hypersensitivity and psychological symptoms are frequent features in irritable bowel syndrome (IBS). Exploring mechanistic pathways leading to visceral hypersensitivity is of importance to direct future studies and treatment options. In this study, we evaluated the contribution of psychological factors to the perception of painful and non-painful rectal sensations in hyper- vs normosensitive IBS patients. METHODS: We included 138 IBS patients (Rome II criteria) who underwent an ascending method of limited rectal balloon distension paradigm. At the end of each distension step, subjects rated the perceived intensity of non-painful ('unpleasantness') and painful rectal sensations on visual analog scales. Sensitivity status was determined based on pain thresholds. Anxiety, depression and somatization were assessed by questionnaires. Mixed models were used to test the relationship between sensitivity status, psychological variables, and pain & unpleasantness ratings upon increasing distension. KEY RESULTS: Hypersensitive IBS patients had lower sensory thresholds for pain, first perception, urge to defecate, and discomfort (p < 0.0001). Upon increasing distension, they rated both painful and non-painful sensations as more intense than normosensitive patients (p < 0.0001). Psychological factors were associated with higher pain ratings during distension in hypersensitive (p < 0.006-0.0001), but not in normosensitive patients. Anxiety, but not depression or somatization, was associated with increased intensity ratings of non-painful sensations (p < 0.001), independent of sensitivity status. CONCLUSIONS & INFERENCES: Hypersensitive IBS patients are characterized by increased perception of pain, but also of non-painful sensations. Psychological factors increase the perception of painful sensations in hypersensitive patients only, whereas non-painful visceral sensations were exaggerated in anxious patients regardless of the sensitivity status.status: publishe

To what extent is bruxism associated with musculoskeletal signs and symptoms? A systematic review

The aim of the present systematic review was to answer the overall research question: “To what extent is bruxism associated with musculoskeletal signs and symptoms?”. The review was performed in accordance with the PRISMA guidelines. A PubMed search of articles published until 23 November 2017 was conducted. The search string included both MeSH terms and text words. Results were presented in categories according to study design, study population (eg, adults, children), bruxism sub‐type (awake, sleep), assessment methods for bruxism and musculoskeletal symptoms (self‐report, validated test) and type of outcome (pain, non‐painful musculoskeletal symptoms). It could be concluded that bruxism is to some extent associated with musculoskeletal symptoms, even though the evidence is conflicting and seems to be dependent on many factors, such as age, whether the bruxism occurs during sleep or wakefulness, and also the quality of the diagnostic methodology regarding bruxism and musculoskeletal signs and symptoms. The literature does not support a direct linear causal relationship between bruxism and such symptoms, but points more in the direction of a multifaceted relationship dependent on the presence of other risk factors. Pain is by far the most commonly assessed symptom, whereas non‐painful musculoskeletal symptoms have generally not been systematically evaluated. In the light of recent findings indicating that non‐painful symptoms may precede TMD pain, it is suggested to increase the scientific focus on non‐painful musculoskeletal symptoms in future studies. Also, future studies should use validated methods for case definition and outcome assessments