Cerebral and cerebrospinal processes underlying counterirritation analgesia.

Pain is a complex experience involving extensive interactions between brain and spinal cord processes. Various interventions that modulate pain, such as the application of a competing noxious stimulus (counterirritation), are thought to involve cerebrospinal regulation through diffuse noxious inhibitory controls (DNICs). However, no study has yet examined the relation between brain and spinal cord activity during counterirritation analgesia in humans. This fMRI study investigates brain responses to phasic painful electrical stimulation administered to the sural nerve to evoke a spinal nociceptive response (RIII reflex) before, during and after counterirritation induced by the immersion of the left contralateral foot in cold water. Responses are compared with a control condition without counterirritation. As expected, counterirritation produced robust pain inhibition with residual analgesia persisting during the recovery period. In contrast, RIII reflex amplitude was significantly decreased by counterirritation only in a subset of subjects. Modulatory effects of counterirritation on pain perception and spinal nociception were paralleled by decreased shock-evoked activity in pain-related areas. Individual changes in shock-evoked brain activity were specifically related to analgesia in primary somatosensory cortex (SI), anterior cingulate cortex and amygdala, and to RIII modulation in supplementary motor area and orbitofrontal cortex (OFC). Moreover, sustained activation induced by the counterirritation stimulus in the OFC predicted shock-pain decrease while sustained activity in SI and the periaqueductal gray matter predicted RIII modulation. These results provide evidence for the implication of at least two partly separable neural mechanisms underlying the effects of counterirritation on pain and spinal nociception in humans.

Understanding online health information: Evaluation, tools, and strategies.

OBJECTIVE: Considering the status of the Internet as a prominent source of health information, assessing online health material has become a central issue in patient education. We describe the strategies available to evaluate the characteristics of online health information, including readability, emotional content, understandability, usability. METHODS: Popular tools used in assessment of readability, emotional content and comprehensibility of online health information were reviewed. Tools designed to evaluate both printed and online material were considered. RESULTS: Readability tools are widely used in online health material evaluation and are highly covariant. Assessment of emotional content of online health-related communications via sentiment analysis tools is becoming more popular. Understandability and usability tools have been developed specifically for health-related material, but each tool has important limitations and has been tested on a limited number of health issues. CONCLUSION: Despite the availability of numerous assessment tools, their overall reliability differs between readability (high) and understandability (low). Approaches combining multiple assessment tools and involving both quantitative and qualitative observations would optimize assessment strategies. PRACTICE IMPLICATIONS: Effective assessment of online health information should rely on mixed strategies combining quantitative and qualitative evaluations. Assessment tools should be selected according to their functional properties and compatibility with target material.

Information quality and dynamics of patients' interactions on tonsillectomy web resources.

Information technologies have drastically altered the way patients gather health-related information. By analysing web resources on tonsillectomy, we expose information quality and dynamics of patients' interactions in the online continuum. Readability was assessed using Flesch Reading Ease (FRE), Flesch Kincaid Grade Level (FKGL), Simple Measure of Gobbledygook (SMOG), and Gunning Fog Index (GFI). Comprehensibility and actionability were assessed using the Patient Education Materials Assessment Tool (PEMAT). Metrics of forums included author characteristics (level of disclosure, gender, age, avatar image, etc.), posts' motive (community support vs. medical information) and content (word count, emoticon use, number of replies, etc.). Analysis of 6 professional medical websites, of 10 health information portals, and of 3 discussion forums totalizing 1369 posts on 358 threads, from January 1, 2007 to December 31, 2014, reveals that online resources exceed understandability recommendations. Women were more present on online health forums (68.2% of authors disclosing their gender) and invested themselves more in their avatar. Authors replying were significantly older than authors of original posts (39.7 ± 0.8 years vs. 29.2 ± 0.9 years, p < 0.001). The degree of self-disclosure was inversely proportional to the requests for medical information (p < 0.001). Men and women were equally seeking medical information (men: 74.0%, women: 77.0%) and community support (men: 65.7%, women: 70.4%), however women responded more supportively (women 86.2%, men 59.1%, p < 0.001). The dynamics of patients' interactions used to overcome accessibility difficulties encountered is complex. This work outlines the necessity for comprehensible medical information to adequately answer patients' needs.

Pain modulation induced by respiration: phase and frequency effects.

The voluntary control of respiration is used as a common means to regulate pain and emotions and is fundamental to various relaxation and meditation techniques. The aim of the present study was to examine how breathing frequency and phase affect pain perception, spinal nociceptive activity (RIII-reflex) and brain activity (scalp somatosensory-evoked potentials - SEP's). In 20 healthy volunteers, painful electric shocks individually adjusted to 120% of the RIII-reflex threshold were delivered to the sural nerve near the end of inspiration or expiration phases, during three cued-breathing conditions: (1) slow breathing (0.1 Hz) with slow (4s) inspiration (0.1Hz-SlowIns), (2) slow breathing (0.1 Hz) with fast (2s) inspiration (0.1 Hz-FastIns), and (3) normal breathing (0.2 Hz) with fast (2s) inspiration (0.2 Hz). Pain ratings were not affected by breathing patterns (p=0.3), but were significantly lower during inspiration compared with expiration (p=0.02). This phase effect was also observed on the N100 component of SEP's, but only in the 0.1-Hz-FastIns condition (p=0.03). In contrast, RIII-reflex amplitude was greater during inspiration compared with expiration (p=0.02). It was also decreased in the 0.1-Hz-SlowIns compared with the 0.2-Hz condition (p=0.01). Slow breathing also increased the amplitude of respiratory sinus arrhythmia (RSA), although these changes were not significantly associated with changes in pain responses. In conclusion, this study shows that pain and pain-related brain activity may be reduced during inspiration but these changes are dissociated from spinal nociceptive transmission. The small amplitude of these effects suggests that factors other than respiration contribute to the analgesic effects of relaxation and meditation techniques.

Widespread hypersensitivity is related to altered pain inhibition processes in irritable bowel syndrome.

The mechanisms of chronic pain in irritable bowel syndrome (IBS) have been widely investigated but remain unclear. The present study investigated the relation between visceral hypersensitivity, cutaneous thermal sensitivity, and central pain mechanisms. Rectal sensitivity was assessed with a barostat, and forearm and calf sensitivity with a contact thermode. Central mechanisms were assessed by counterirritation using sustained cold-pain to the hand and painful electric shocks to the ankle. Psychological symptoms were also assessed, using questionnaires. Female volunteers with diarrhea-predominant IBS (n=27) and healthy controls (n=25) participated in the study. IBS patients had lower rectal and calf pain thresholds compared to controls (p's<0.05). IBS patients also reported more pain than controls for rectal distensions, and heat pain on the calf and forearm (all p's<0.001). Cold-pain inhibited shock-pain in controls but not IBS patients (controls: -13.5+/-5.3 vs IBS: +1.9+/-10.5; p<0.01). In addition, visceral hypersensitivity was significantly correlated to cutaneous thermal hypersensitivity and pain inhibition deficits, although effects were only weak and moderate, respectively. Furthermore, covariance analyses indicated that psychological factors accounted for group differences in visceral hypersensitivity and pain inhibition deficits. In conclusion, this study confirms the relation between altered pain inhibition processes and widespread hypersensitivity in IBS. The present results also suggests that psychological symptoms and altered pain processing in IBS patients may reflect at least in part, common underlying mechanisms.