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.

Background: 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.

"Living more and struggling less": a qualitative descriptive study of patient experiences of physiotherapy informed by Acceptance and Commitment Therapy within a multidisciplinary pain management programme.

OBJECTIVES: Physiotherapists increasingly deliver treatment informed by cognitive-behavioural therapy, including Acceptance and Commitment Therapy (ACT), for persistent pain. This study explored patients' experiences of ACT-informed physiotherapy to better understand therapeutic processes and outcomes. DESIGN: A qualitative descriptive study was conducted. Focus groups explored participants' experience of ACT-informed physiotherapy in the context of a pain management programme. Responses were audio recorded, transcribed verbatim, and analysed using a hybrid inductive-deductive reflexive thematic analysis. SETTING: A single tertiary care pain management service. PARTICIPANTS: The sample consisted of fifteen patients from two treatment groups who completed an intensive multidisciplinary ACT-based pain management programme. Participants were included irrespective of their treatment response. RESULTS: One overarching theme (living more and struggling less) and four interconnected themes were generated from the data: 1) awareness and openness help to approach physical activities flexibly; 2) from battling against to working with the body compassionately; 3) from narrow focus to curiosity, freedom, and expansion; and 4) social connection is a catalyst for openness and engagement. CONCLUSIONS: Participants experienced ACT-informed physiotherapy as helping them to live more and struggle less with pain; this occurred in the context of a psychologically flexible relationship with the physiotherapist and was catalysed by social connection. These findings should be seen as preliminary given the small number and relatively brief duration of focus groups conducted. Further research is needed to explore how principles within ACT-informed physiotherapy may support patients and clinicians to respond effectively to the challenges that persistent pain can bring.

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.

A theoretically guided approach to identifying predictors of treatment outcome in Contextual Cognitive Behavioural Therapy for chronic pain.

BACKGROUND: Psychological treatments are known to be effective for chronic pain, but little is understood about which patients are most likely to benefit from which ones. METHODS: The study reported here included 609 people who attended a residential, interdisciplinary, pain management programme based on Acceptance and Commitment Therapy between January 2012 and August 2014. A flexible and theoretically guided approach to model building based on fractional polynomials was used to identify potential predictors of outcome in domains of emotional, physical and social functioning and pain intensity. Variables considered for inclusion were baseline demographic variables along with measures reflecting processes of psychological flexibility, including acceptance, cognitive defusion and committed action. RESULTS: Employment status, level of distress, decentring (a process like cognitive defusion) and acceptance significantly contributed to the model above and beyond the effects of other baseline variables. The unique effects of these were small but may be clinically relevant. CONCLUSIONS: Future research should continue to investigate moderators of treatment outcome and to explicitly link these to treatment mechanisms. Taking a flexible, theoretically driven approach to modelling continuous outcomes may be valuable in furthering our understanding of which patients might respond best to which treatments. SIGNIFICANCE: Further research is needed to better understand who benefits most from psychological treatments for chronic pain. This study suggests that a flexible, multivariate and theoretical approach to identifying predictors of outcome may be valuable in furthering research in this area.

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

BACKGROUND: Experimental and clinical evidence support a link between body representations 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 = 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.

Phenomenology, epidemiology, co-morbidity and treatment of a specific phobia of vomiting: A systematic review of an understudied disorder.

Specific Phobia of Vomiting (SPOV) is an under-researched disorder compared to other Specific Phobias. A systematic review was conducted to synthesise existing research across areas of phenomenology, aetiology, epidemiology, co-morbidity, assessment measures and treatment. Online databases (Psychinfo, Embase, Medline, Pubmed and Cochrane Library) were searched using terms related to SPOV and 'emetophobia'. A manual search of reference lists of included papers was also conducted. In total, 385 articles were found and 24 were included in the review. The review was registered on the PROSPERO register (CRD42016046378). The review presents a qualitative synthesis of identified studies exploring the features of SPOV including locus of fear, feared consequences of vomiting, and common safety and avoidance behaviours. It also identified articles describing aetiological factors involved in the development of SPOV, co-morbid disorders and the epidemiology of the disorder. Further studies focused on valid and reliable measures to assess SPOV, and treatments that are effective at reducing symptomatology of SPOV and psychological distress. There are relatively few published research articles on SPOV, and particularly high quality studies exploring effective treatment options for SPOV. Further research should focus on RCTs for comparing different approaches to reducing symptomatology and distress in people with SPOV.

Predictors of Treatment Outcome in Contextual Cognitive and Behavioral Therapies for Chronic Pain: A Systematic Review.

There is increasing evidence that contextual forms of cognitive-behavioral therapy (CBT) are effective in the management of chronic pain, yet little is understood about the factors that moderate or predict outcomes in these treatments. This systematic review aimed to identify pretreatment participant characteristics associated with positive treatment responses in contextual CBT for chronic pain. Medline, EMBASE, PsychINFO, and CENTRAL were searched to identify eligible studies. Studies were included if the participants were adults with chronic pain, designs were longitudinal, treatments focused on psychological flexibility or mindfulness, and reported results allowed for examination of moderators or predictors of standard treatment outcomes. Of 991 records initially identified, 20 were eligible for inclusion in the review. Some evidence suggested that baseline emotional functioning predicts treatment response, but the direction of this association varied between studies. Substantive findings were inconsistent and inconclusive, however, methodological limitations were consistent. These included treatment heterogeneity, and a lack of theoretical, a priori guidance in examining potential predictors. Future research should adopt a theoretically based approach to examining moderators in relation to specific treatment methods and therapeutic processes. Considering moderation without first considering mediation is probably a limited strategy. PERSPECTIVE: In this systematic review we examined evidence for potential predictors or moderators of outcomes in contextual CBT for chronic pain. Substantive findings were inconclusive but important methodological limitations and a lack of theoretical guidance were found. Future research should explicitly plan relevant methods and follow clear theoretical models.

Relative contributions of spatial weighting, explicit knowledge and proprioception to hand localisation during positional ambiguity.

When vision and proprioception are rendered incongruent during a hand localisation task, vision is initially weighted more than proprioception in determining location, and proprioception gains more weighting over time. However, it is not known whether, under these incongruency conditions, particular areas of space are also weighted more heavily than others, nor whether explicit knowledge of the sensory incongruence (i.e. disconfirming the perceived location of the hand) modulates the effect. Here, we hypothesised that both non-informative inputs coming from one side of space and explicit knowledge of sensory incongruence would modulate perceived location of the limb. Specifically, we expected spatial weighting to shift hand localisation towards the weighted area of space, and we expected greater weighting of proprioceptive input once perceived location was demonstrated to be inaccurate. We manipulated spatial weighting using an established auditory cueing paradigm (Experiment 1, n = 18) and sensory incongruence using the 'disappearing hand trick' (Experiment 2, n = 9). Our first hypothesis was not supported-spatial weighting did not modulate hand localisation. Our second hypothesis was only partially supported-disconfirmation of hand position did lead to more accurate localisations, even if participants were still unaware of their hand position. This raised the possibility that rather than disconfirmation, a simple movement of the hand in view could update the sensory-motor system, by immediately increasing the weighting of proprioceptive input relative to visual input. This third hypothesis was then confirmed (Experiment 3, n = 9). These results suggest that hand localisation is robust in the face of differential weighting of space, but open to modulation in a modality-specific manner, when one sense (vision) is rendered inaccurate.

Untangling visual and proprioceptive contributions to hand localisation over time.

Previous studies showed that self-localisation ability involves both vision and proprioception, integrated into a single percept, with the tendency to rely more heavily on visual than proprioceptive cues. Despite the increasing evidence for the importance of vision in localising the hands, the time course of the interaction between vision and proprioception during visual occlusion remains unclear. In particular, we investigated how the brain weighs visual and proprioceptive information in hand localisation over time when the visual cues do not reflect the real position of the hand. We tested three hypotheses: Self-localisations are less accurate when vision and proprioception are incongruent; under the same conditions of incongruence, people first rely on vision and gradually revert to proprioception; if vision is removed immediately prior to hand localisation, accuracy increases. Sixteen participants viewed a video of their hands, under three conditions each undertaken with eyes open or closed: Incongruent conditions (right hand movement seen: inward, right hand real movement: outward), Congruent conditions (movement seen congruent to real movement). The right hand was then hidden from view and participants performed a localisation task whereby a moving vertical arrow was stopped when aligned with the felt position of their middle finger. A second experiment used identical methodology, but with the direction of the arrow switched. Our data showed that, in the Incongruent conditions (both with eyes open and closed), participants perceived their right hand close to its last seen position. Over time, the perceived position of the hand shifted towards the physical position. Closing the eyes before the localisation task increased the accuracy in the Incongruent condition. Crucially, Experiment 2 confirmed the findings and showed that the direction of arrow movement had no effect on hand localisation. Our hypotheses were supported: When vision and proprioception were incongruent, participants were less accurate and initially relied on vision and then proprioception over time. When vision was removed, this shift occurred more quickly. Our findings are relevant in understanding the normal and pathological processes underpinning self-localisation.

Evidence for distorted mental representation of the hand in osteoarthritis.

OBJECTIVES: Some chronic pain states are associated with a distortion of the perceived size or shape of the painful area, and multisensory illusions that disrupt these dimensions can modulate pain in healthy controls and people with painful disorders. Illusory hand resizing has recently been found to relieve pain in hand OA, raising the possibility that the illusion corrects some underlying perceptual disturbance. We evaluated this possibility by measuring perceived hand size in healthy controls and those with painful hand OA before and after illusory hand resizing. The aim was to investigate whether people with painful hand OA have distorted representations of hand size and whether these representations are malleable. We hypothesized that hand OA is associated with a distorted mental representation of the painful hand and that perceived hand size can be modulated via multisensory illusion. METHODS: Twelve volunteers with painful hand OA and 12 healthy age-matched controls performed three tasks (hand stretch, hand shrink and no illusion) in a randomized order then estimated the size of their hand using an adjustable photographic image. RESULTS: Our hypotheses were supported: under normal conditions, perceived hand size was smaller for the OA group than for healthy controls, consistent with a distorted mental representation of the painful hand. Furthermore, illusory stretching increased perceived hand size in both groups, while illusory shrinking decreased perceived hand size in healthy controls but not in the OA group. CONCLUSION: These results suggest that hand OA is associated with a distorted mental representation of the painful hand and are consistent with the idea that the pain relief offered by multisensory illusions may work via normalization of this distortion.