An exploratory investigation into the longevity of pain reduction following multisensory illusions designed to alter body perception

BACKGROUND: Previous research suggests that multisensory body illusions that alter the conscious bodily experience can modulate pain in osteoarthritis, which may be a result of modifying cortical misrepresentations of the painful body part. However, the longevity and underlying mechanisms of such illusion-induced analgesia is unknown. OBJECTIVES: This study aimed to investigate the therapeutic potential of body illusions, specifically examining the longevity of pain relief and effects on subjective joint flexibility. We also aimed to test if illusory-induced analgesia was due to limb disownership, which is also thought to be affected by body illusions. METHOD: Multisensory stretch and shrink illusions were used to manipulate mental representations in hand osteoarthritis. Experiment 1 examined longevity of analgesia by comparing pre-illusion pain ratings with post-illusion ratings taken immediately and over a period of four minutes both with and without vision of the manipulated limb. Experiment 2 compared changes in subjective flexibility between the illusion types. Experiment 3 tested whether an illusion that induced a temporary experience of hand loss would indicate limb disownership as a mechanism for modulating pain during body illusions. RESULTS: Illusion-induced analgesia was found to outlast the direct application of both shrink and stretch illusions. Illusory stretching provided more clinically significant pain reduction along with increased subjective flexibility. Disownership of the limb had no effect on pain ratings. CONCLUSIONS: Illusory stretching of the joints in osteoarthritis may have significant clinical potential in development of future pain treatments. The results are also compatible with theories of cortical involvement of pain in osteoarthritis

Illusory resizing of the painful knee is analgesic in symptomatic knee osteoarthritis

Background. Experimental and clinical evidence support a link between body represen- tations and pain. This proof-of-concept study in people with painful knee osteoarthritis (OA) aimed to determine if: (i) visuotactile illusions that manipulate perceived knee size are analgesic; (ii) cumulative analgesic effects occur with sustained or repeated illusions. Methods. Participants with knee OA underwent eight conditions (order randomised): stretch and shrink visuotactile (congruent) illusions and corresponding visual, tactile and incongruent control conditions. Knee pain intensity (0-100 numerical rating scale; 0 = no pain at all and 100 D worst pain imaginable) was assessed pre- and post- condition. Condition (visuotactile illusion vs control) × Time (pre-/post-condition) repeated measure ANOVAs evaluated the effect on pain. In each participant, the most beneficial illusion was sustained for 3 min and was repeated 10 times (each during two sessions); paired t -tests compared pain at time 0 and 180s (sustained) and between illusion 1 and illusion 10 (repeated). Results. Visuotactile illusions decreased pain by an average of 7.8 points (95% CI [2.0-13.5]) which corresponds to a 25% reduction in pain, but the tactile only and visual only control conditions did not (Condition × Time interaction: p = 0:028). Visuotactile illusions did not differ from incongruent control conditions where the same visual manipulation occurred, but did differ when only the same tactile input was applied. Sustained illusions prolonged analgesia, but did not increase it. Repeated illusions increased the analgesic effect with an average pain decrease of 20 points (95% CI [6.9-33.1])-corresponding to a 40% pain reduction. Discussion. Visuotactile illusions are analgesic in people with knee OA. Our results suggest that visual input plays a critical role in pain relief, but that analgesia requires multisensory input. That visual and tactile input is needed for analgesia, supports multisensory modulation processes as a possible explanatory mechanism. Further research exploring the neural underpinnings of these visuotactile illusions is needed. For potential clinical applications, future research using a greater dosage in larger samples is warranted

Management of latent Mycobacterium tuberculosis infection:WHO guidelines for low tuberculosis burden countries

ABSTRACT Latent tuberculosis infection (LTBI) is characterised by the presence of immune responses to previously acquired Mycobacterium tuberculosis infection without clinical evidence of active tuberculosis (TB). Here we report evidence-based guidelines from the World Health Organization for a public health approach to the management of LTBI in high risk individuals in countries with high or middle upper income and TB incidence of <100 per 100000 per year. The guidelines strongly recommend systematic testing and treatment of LTBI in people living with HIV, adult and child contacts of pulmonary TB cases, patients initiating anti-tumour necrosis factor treatment, patients receiving dialysis, patients preparing for organ or haematological transplantation, and patients with silicosis. In prisoners, healthcare workers, immigrants from high TB burden countries, homeless persons and illicit drug users, systematic testing an

An exploratory investigation into the longevity of pain reduction following multisensory illusions designed to alter body perception

© 2019 Background: Previous research suggests that multisensory body illusions that alter the conscious bodily experience can modulate pain in osteoarthritis, which may be a result of modifying cortical misrepresentations of the painful body part. However, the longevity and underlying mechanisms of such illusion-induced analgesia is unknown. Objectives: This study aimed to investigate the therapeutic potential of body illusions, specifically examining the longevity of pain relief and effects on subjective joint flexibility. We also aimed to test if illusory-induced analgesia was due to limb disownership, which is also thought to be affected by body illusions. Method: Multisensory stretch and shrink illusions were used to manipulate mental representations in hand osteoarthritis. Experiment 1 examined longevity of analgesia by comparing pre-illusion pain ratings with post-illusion ratings taken immediately and over a period of four minutes both with and without vision of the manipulated limb. Experiment 2 compared changes in subjective flexibility between the illusion types. Experiment 3 tested whether an illusion that induced a temporary experience of hand loss would indicate limb disownership as a mechanism for modulating pain during body illusions. Results: Illusion-induced analgesia was found to outlast the direct application of both shrink and stretch illusions. Illusory stretching provided more clinically significant pain reduction along with increased subjective flexibility. Disownership of the limb had no effect on pain ratings. Conclusions: Illusory stretching of the joints in osteoarthritis may have significant clinical potential in development of future pain treatments. The results are also compatible with theories of cortical involvement of pain in osteoarthritis

Examining the association between group context effects and individual outcomes in an interdisciplinary group-based treatment for chronic pain based on acceptance and commitment therapy

ackground: Although cognitive-behavioural treatments for chronic pain are delivered in groups, there is little research investigating group effects in these treatments. Purpose: The aim of this study was to investigate associations between group composition variables at the start of treatment and individual outcomes following intensive interdisciplinary treatment for pain based on Acceptance and Commitment Therapy. Methods: This was a secondary analysis of routinely collected observational data. Five-hundred and sixteen patients completed a standard set of demographic, pain-related and psychosocial measures at pre- and post-treatment. Intracluster correlations (ICCs) were computed to examine the clustering of outcomes within groups and multilevel models explored the association between group composition variables and individual level outcomes. Results: The ICCs for pain intensity (0.11) and interference (0.09) suggested that multilevel models were warranted for these outcomes, while a multilevel model for post-treatment depression (ICC = 0.04) was not warranted. Group percentage of participants receiving disability benefits and group mean pain intensity at pre-treatment were significantly positively associated with individual level pain intensity at post-treatment, controlling for pre-treatment individual level pain intensity. Group mean pain intensity at pre-treatment was the only group variable that significantly predicted post-treatment pain interference at the individual level. Psychosocial group composition variables were not significantly associated with individual level outcomes. Conclusion: Given the limited predictive utility of group composition variables in the current study, future research should undertake direct assessment of group level therapeutic and countertherapeutic processes to advance understanding of who benefits from group treatments for pain and how. As the variance in outcomes accounted for by group clustering was relatively small and significant within groups variance remained, research is also needed to further understand individual level factors that influence cognitive-behavioural treatment outcomes for pain