Get Your Head in the Game: A Replicated Single-Case Experimental Design Evaluating the Effect of a Novel Virtual Reality Intervention in People With Chronic Low Back Pain.

Chronic low back pain (CLBP) is a leading cause of disability worldwide. Contemporary treatment of CLBP is suboptimal, with small-moderate effect sizes and high relapse rates. Virtual reality (VR) is an increasingly accessible technology that can improve adherence to exercise programs through gamification. Using VR to facilitate exercise adherence and enjoyment may improve the clinical outcomes. This study aimed to evaluate the effects of a gamified VR graded activity intervention in people with CLBP, using commercially available and bespoke VR programs. A sequentially replicated, multiple-baseline, randomized AB single-case experimental design was undertaken in 10 people with CLBP. Outcomes were assessed daily and included pain intensity (primary) and pain catastrophizing, pain-related fear, and anxiety/worry (secondary). The effect of the intervention on the primary outcome was evaluated using a multilevel-model, nonparametric randomization test. The VR graded activity intervention resulted in a significant reduction in pain intensity (effect estimate = -1.0, standard error = .27, P < .0011) with 4 participants achieving ≥30% pain reduction (minimum important change). There was a significant effect of the intervention on pain catastrophizing but not pain-related fear or anxiety/worry measures. These findings provide preliminary support for a VR graded activity program to reduce pain in people with CLBP. PERSPECTIVE: This novel, VR graded activity intervention reduced pain intensity and catastrophizing in people with CLBP. The intervention also had high adherence and enjoyment. Given that this intervention involved 2 freely available VR programs, it can be easily translated into clinical practice.

Increased positive affect is associated with less generalization of pain-related avoidance.

Fear-avoidance models of chronic pain consider excessive spreading (or overgeneralization) of pain-related avoidance toward safe activities to play a crucial role in chronic pain disability. This study (N = 96) investigated whether avoidance generalization is mitigated by positive affect induction. Pain-free, healthy participants performed an arm-reaching task during which certain movements were followed by pain, while another was not. One group then performed an exercise to induce positive affect (positive affect group), while another group performed a neutral exercise (neutral group). A third group also performed the neutral exercise, but did not learn to avoid pain during the arm-reaching task (yoked neutral group). To test generalization, we introduced novel but similar movements that were never followed by pain in all groups. Results showed no differences in generalization between the positive affect and neutral groups; however, across groups, higher increases in positive affect were associated with less generalization of avoidance, and less generalization of pain-expectancy and pain-related fear. Compared to the yoked neutral group, the neutral group showed avoidance generalization, as well as pain-expectancy and pain-related fear generalization. These results point toward the potential of positive affect interventions in attenuating maladaptive spreading of pain-related avoidance behavior to safe activities.

Alike, But Not Quite: Comparing the Generalization of Pain-Related Fear and Pain-Related Avoidance.

Pain-related fear and -avoidance crucially contribute to pain chronification. People with chronic pain may adopt costly avoidance strategies above and beyond what is necessary, aligning with experimental findings of excessive fear generalization to safe movements in these populations. Furthermore, recent evidence suggests that, when avoidance is costly, it can dissociate from fear. Here, we investigated whether concurrently measured pain-related fear and costly avoidance generalization correspond in one task. We also explored whether healthy participants avoid excessively despite associated costs, and if avoidance would decrease as a function of dissimilarity from a pain-associated movement. In a robotic arm-reaching task, participants could avoid a low-cost, pain-associated movement trajectory (T+), by choosing a high-cost non-painful movement trajectory (T-), at opposite ends of a movement plane. Subsequently, in the absence of pain, we introduced three movement trajectories (G1-3) between T+ and T-, and one movement trajectory on the side of T- opposite to T+ (G4), linearly increasing in costs from T+ to G4. Avoidance was operationalized as maximal deviation from T+, and as trajectory choice. Fear learning was measured using self-reported pain-expectancy, pain-related fear, and startle eye-blink electromyography. Self-reports generalized, both decreasing with increasing distance from T+. In contrast, all generalization trajectories were chosen equally, suggesting that avoidance-costs and previous pain balanced each other out. No effects emerged in the electromyography. These results add to a growing body of literature showing that (pain-related) avoidance, especially when costly, can dissociate from fear, calling for a better understanding of the factors motivating, and mitigating, disabling avoidance. PERSPECTIVE: This article presents a comparison of pain-related fear- and avoidance generalization, and an exploration of excessive avoidance in healthy participants. Our findings show that pain-related avoidance can dissociate from fear, especially when avoidance is costly, calling for a better understanding of the factors motivating and mitigating disabling avoidance.

Generalization of instrumentally acquired pain-related avoidance to novel but similar movements using a robotic arm-reaching paradigm.

Avoidance is considered a key contributor to the development and maintenance of chronic pain disability, likely through its excessive generalization. This study investigated whether acquired avoidance behavior generalizes to novel but similar movements. Using a robotic arm, participants moved their arm from a starting to a target location via one of three possible movement trajectories. For the Experimental Group, the shortest, easiest trajectory was always paired with pain (T1 = 100% reinforcement/no resistance and deviation). Pain could be partly or completely avoided by choosing increasingly effortful movements (T2 = 50% reinforcement, moderate resistance/deviation; T3 = 0% reinforcement, strongest resistance/largest deviation). A Yoked Group received the same number of painful stimuli irrespective of their own behavior. Outcomes were self-reported fear of movement-related pain, pain-expectancy, avoidance behavior, (maximal deviation from the shortest trajectory), and trajectory choice behavior. We tested generalization to three novel trajectories (G1-3) positioned next to the acquisition trajectories. Whereas acquired fear of movement-related pain and pain-expectancy generalized in the Experimental Group, avoidance behavior did not, suggesting that threat beliefs and high-cost avoidance may not be directly related. The lack of avoidance generalization may be due to a perceived context-switch in the configurations of the acquisition and the generalization phases.

The relationship between fear generalization and pain modulation: an investigation in healthy participants.

Background and aims Pain-related fear and its subsequent generalization is key to the development and maintenance of chronic pain disability. Research has shown that pain-related fear acquired through classical conditioning generalizes following a gradient, that is, novel movements that are proprioceptively similar to the original pain-associated movement elicit more fear. Studies suggest that classical conditioning can also modulate pain and conditioned fear seems to mediate this effect. However, it remains uninvestigated whether this is also the case for generalized fear. Methods In a voluntary joystick movement paradigm, one movement (conditioned stimulus; CS+) was followed by pain (pain-US), and another was not (CS-). Generalization to five novel movements (generalization stimuli; GSs) with varying levels of similarity to the CSs was tested when paired with an at-pain-threshold intensity stimulus (threshold-USs). We collected self-reported fear and pain, as well as eyeblink startle responses as an additional index of conditioned fear. Results Results showed a fear generalization gradient in the ratings, but not in the startle measures. The data did not support the idea that fear generalization mediates spreading of pain. Conclusions Despite the lack of effects in the current study, this is a promising novel approach to investigate pain modulation in the context of chronic pain. Implications This study replicates the finding that pain-related fear spreads selectively towards movements that are proprioceptively more similar to the original pain-eliciting movement. Although results did not support the idea that such generalized fear mediates spreading of pain, the study provides a promising approach to investigate pain modulation by pain-associated movements.

Goal conflict in chronic pain: day reconstruction method.

BACKGROUND: When suffering from chronic pain, attempts to control or avoid pain often compete with other daily activities. Engaging in one activity excludes engaging in another, equally valued activity, which is referred to as "goal conflict." As yet, the presence and effects of goal conflicts in patients with chronic pain remain poorly understood. METHODS: This study systematically mapped the presence and experience of goal conflicts in patients with fibromyalgia compared to healthy controls. A total of 40 patients and 37 controls completed a semi-structured interview in which they first reconstructed the previous day, identified conflicts experienced during that day, and classified each of the conflicting goals in one of nine goal categories. Additionally, they assessed how they experienced the previous day and the reported conflicts. RESULTS: Results showed that patients did not experience more goal conflicts than healthy controls, but that they did differ in the type of conflicts experienced. Compared to controls, patients reported more conflicts related to pain, and fewer conflicts involving work-related, social or pleasure-related goals. Moreover, patients experienced conflicts as more aversive and more difficult to resolve than control participants. DISCUSSION: This study provides more insight in the dynamics of goal conflict in daily life, and indicates that patients experience conflict as more aversive than controls, and that conflict between pain control (and avoidance) and other valued activities is part of the life of patients.

A sigh of relief or a sigh of expected relief: Sigh rate in response to dyspnea relief.

Research has suggested that sighs may serve a regulatory function during stress and emotions by facilitating relief. Evidence supports the hypotheses that sighs both express and induce relief from stress. To explore the potential role of sighs in the regulation of symptoms, the present study aimed to investigate the relationship between sighs and relief of symptoms, and relief of dyspnea, specifically. Healthy volunteers participated in two studies (N = 44, N = 47) in which dyspnea was induced by mild (10 cmH2 O/l/s) or high (20 cmH2 0/l/s) inspiratory resistances. Dyspnea relief was induced by the offset of the inspiratory resistances (transitions from high and mild inspiratory resistance to no resistance). Control comparisons included dyspnea increases (transitions from no or mild inspiratory resistance to high inspiratory resistance) and dyspnea continuations (continuations of either no resistance or a high resistance). In Experiment 1, dyspnea levels were cued. In Experiment 2, no cues were provided. Sigh rate during dyspnea relief was significantly higher compared to control conditions, and sigh rate increased as self-reported dyspnea decreased. Additionally, sigh rate was higher during cued dyspnea relief compared to noncued dyspnea relief. These results suggest that sighs are important markers of dyspnea relief. Moreover, sighs may importantly express dyspnea relief, as they are related to experiential dyspnea decreases and occur more frequently during expected dyspnea relief. These findings suggest that sighs may not only be important in the regulation of stress and emotions, but also may be functional in the regulation of dyspnea.

Sigh rate during emotional transitions: More evidence for a sigh of relief.

Evidence suggests that sighs regulate stress and emotions, e.g. by facilitating relief. This study aimed to investigate sigh rates during relief. In addition, links between sighs, anxiety sensitivity and HPA-axis activity were explored. Healthy volunteers (N=29) were presented cues predicting the valence of subsequent stimuli. By sequencing cues that predicted pleasant or unpleasant stimuli with or without certainty, transitions to certain pleasantness (relief) or to certain unpleasantness (control) were created and compared to no transitions. Salivary cortisol, anxiety sensitivity and respiration were measured. Sigh frequency was significantly higher during relief than during control transitions and no transition states, and higher during control transitions than during no transition states. Sigh frequency increased with steeper cortisol declines for high anxiety sensitive persons. Results confirm a relationship between sighs and relief. In addition, results suggest that sigh frequency is importantly related to HPA-axis activity, particularly in high anxiety sensitive persons.

Extinction of Fear Generalization: A Comparison Between Fibromyalgia Patients and Healthy Control Participants.

Fear learning deficiencies might contribute to the development and maintenance of chronic pain disability. Fear is often not restricted to movements (conditioned stimulus [CS+]) originally associated with pain (unconditioned stimulus), but expands to similar movements (generalization stimuli [GSs]). This spreading of fear becomes dysfunctional when overgeneralization to safe stimuli occurs. More importantly, persistence of pain-related fear to GSs despite corrective feedback might even be more debilitating and maintain long-term chronic pain disability. Yet, research on this topic is lacking. Using a voluntary joystick movement paradigm, we examined (extinction of) pain-related fear generalization in fibromyalgia patients (FM) and healthy control participants (HC). During acquisition, one movement (CS+) predicted pain; another did not (CS-). We tested (extinction of) fear generalization to 5 GSs varying in similarity with the CS+ and CS-. Results revealed flatter pain expectancy generalization gradients in FM than in HC due to elevated responses to GSs more similar to the CS-; the fear generalization gradients did not differ. Although pain-related fear and expectancy to the GSs decreased during extinction, responses to the GSs remained higher for FM than HC, suggesting that extinction of generalization is impaired in chronic pain patients. Persistence of excessive protective responses may contribute to maintaining long-term chronic pain disability. PERSPECTIVE: Pain-related fear and expectancy to movements-varying in similarity with the original painful and nonpainful movement-decrease during extinction in HC and FM. Yet, conditioned responses remain elevated in patients despite corrective feedback, indicating impaired extinction of generalization. Persistent excessive protective responses may contribute to preserving pain disability.

Pain Catastrophizing and Fear of Pain Predict the Experience of Pain in Body Parts Not Targeted by a Delayed-Onset Muscle Soreness Procedure.

UNLABELLED: The present study examined whether pain catastrophizing and pain-related fear predict the experience of pain in body regions that are not targeted by an experimental muscle injury protocol. A delayed-onset muscle soreness (DOMS) protocol was used to induce pain unilaterally in the pectoralis, serratus, trapezius, latissimus dorsi, and deltoid muscles. The day after the DOMS protocol, participants were asked to rate their pain as they lifted weighted canisters with their targeted (ie, injured) arm and their nontargeted arm. The lifting task is a nonnoxious stimulus unless participants are already experiencing musculoskeletal pain. Therefore, reports of pain on the nontargeted arm were operationalized as pain in response to a nonnoxious stimulus. Eighty-two healthy university students (54 men, 28 women) completed questionnaires on pain catastrophizing and fear of pain and went through the DOMS protocol. The analyses revealed that catastrophizing and pain-related fear prospectively predicted pain experience in response to a nonnoxious stimulus. The possible mechanisms underlying this effect and clinical implications are discussed. PERSPECTIVE: Pain catastrophizing and fear of pain prospectively predict the pain experience in response to a nonnoxious stimulus. The pattern of findings is consistent with the predictions of current models of generalization of pain-related fear.

Can experimentally induced positive affect attenuate generalization of fear of movement-related pain?

UNLABELLED: Recent experimental data show that associative learning processes are involved not only in the acquisition but also in the spreading of pain-related fear. Clinical studies suggest involvement of positive affect in resilience against chronic pain. Surprisingly, the role of positive affect in associative learning in general, and in fear generalization in particular, has received scant attention. In a voluntary movement paradigm, in which one arm movement (reinforced conditioned stimulus [CS+]) was followed by a painful stimulus and another was not (unreinforced conditioned stimulus [CS-]), we tested generalization of fear inhibition in response to 5 novel but related generalization movements (GSs; within-subjects) after either a positive affect induction or a control exercise (Group = between-subjects) in healthy participants (N = 50). The GSs' similarity with the original CS+ movement and CS- movement varied. Fear learning was assessed via verbal ratings. Results indicated that there was an interaction between the increase in positive affect and the linear generalization gradient. Stronger increases in positive affect were associated with steeper generalization curves because of relatively lower pain-unconditioned stimulus expectancy and less fear of stimuli more similar to the CS-. There was no Group by Stimulus interaction. Results thus suggest that positive affect may enhance safety learning through promoting generalization from known safe movements to novel yet related movements. Improved safety learning may be a central mechanism underlying the association between positive affect and increased resilience against chronic pain. PERSPECTIVE: We investigated the extent to which positive affect influences the generalization (ie, spreading) of pain-related fear inhibition in response to situations similar to the original, pain-eliciting situation. Results suggest that increasing positive affect in the acute pain stage may limit the spreading of pain-related fear, thereby potentially inhibiting transition to chronic pain conditions.

Factors determining the smooth flow and the non-operative time in a one-induction room to one-operating room setting.

RATIONALE, AIMS AND OBJECTIVES: What factors determine the use of an anaesthesia preparation room and shorten non-operative time? METHODS: A logistic regression is applied to 18 751 surgery records from AZ Sint-Jan Brugge AV, Belgium, where each operating room has its own anaesthesia preparation room. Surgeries, in which the patient's induction has already started when the preceding patient's surgery has ended, belong to a first group where the preparation room is used as an induction room. Surgeries not fulfilling this property belong to a second group. A logistic regression model tries to predict the probability that a surgery will be classified into a specific group. Non-operative time is calculated as the time between end of the previous surgery and incision of the next surgery. A log-linear regression of this non-operative time is performed. RESULTS: It was found that switches in surgeons, being a non-elective surgery as well as the previous surgery being non-elective, increase the probability of being classified into the second group. Only a few surgery types, anaesthesiologists and operating rooms can be found exclusively in one of the two groups. Analysis of variance demonstrates that the first group has significantly lower non-operative times. Switches in surgeons, anaesthesiologists and longer scheduled durations of the previous surgery increases the non-operative time. A switch in both surgeon and anaesthesiologist strengthens this negative effect. Only a few operating rooms and surgery types influence the non-operative time. CONCLUSION: The use of the anaesthesia preparation room shortens the non-operative time and is determined by several human and structural factors.

Positive affect protects against deficient safety learning during extinction of fear of movement-related pain in healthy individuals scoring relatively high on trait anxiety.

UNLABELLED: From a treatment perspective, it is highly relevant to pinpoint individual vulnerability factors for resistance to exposure treatment in highly fearful chronic pain patients. Previous fear conditioning research showed that healthy individuals scoring relatively high on trait anxiety display sustained fear to safety cues during extinction. In the context of fear of movement-related pain, this intriguing question has been largely neglected so far. Even more importantly, positive psychological traits such as trait positive affect may function as protective factors against the spreading of fear to safe movements and improve exposure treatment outcomes. In this study, healthy participants completed a trait anxiety and trait positive affect questionnaire and underwent acquisition and extinction of fear of movement-related pain using an experimental voluntary movement paradigm. During acquisition, one movement (CS+) was paired with a painful stimulus and another movement was not (CS-). During extinction, the CS+ was no longer reinforced. Results show failure of fear inhibition to the CS- during extinction in healthy individuals scoring relatively high on trait anxiety or relatively low on positive affect. These findings seem to suggest that safety learning is more vulnerable in healthy people with a high anxious disposition and/or relatively lower levels of positive affect. In addition, this is the first study to show that the negative impact of high trait anxiety on fear inhibition to safety cues during extinction can be countered by high levels of positive affect. These findings may have important clinical implications. PERSPECTIVE: Both low positive affect and high trait anxiety are associated with impaired fear inhibition to nonpainful movements during fear extinction. Interestingly, high levels of positive affect buffer against the negative impact of trait anxiety. Increasing positive affect during exposure may counter the effects of trait vulnerabilities and improve treatment outcomes.

Latent variable models for partially ordered responses and trajectory analysis of anger-related feelings.

A general framework is presented for the analysis of partially ordered set (poset) data. The work is motivated by the need to analyse poset data such as multi-componential responses in psychological measurement and partially accomplished cognitive tasks in educational measurement. It is shown how the generalized loglinear model can be used to represent poset data that form a lattice and how latent-variable models can be constructed by further specifying the canonical parameters of the loglinear representation. The approach generalizes a class of latent-variable models for completely ordered data. We apply the methods to analyse data on the frequency and intensity of anger-related feelings. Furthermore, we propose a trajectory analysis to gain insight into the response function of partially ordered emotional states.

Mixed model estimation methods for the Rasch model.

Mixed models take the dependency between observations based on the same person into account by introducing one or more random effects. After introducing the mixed model framework, it is explained, by taking the Rasch model as a generic example, how item response models can be conceptualized as generalized linear and nonlinear mixed models. Common estimation methods for generalized linear and nonlinear models are discussed. In a simulation study, the performance of four estimation methods is assessed for the Rasch model under different conditions regarding the number of items and persons, and the degree of interindividual differences. The estimation methods included in the study are: an approximation of the integral over the random effect by means of Gaussian quadrature; direct maximization with a sixth-order Laplace approximation to the integrand; a linearized approximation of the nonlinear model employing PQL2; and finally a Bayesian MCMC method. It is concluded that the estimation methods perform almost equally well, except for a slightly worse recovery of the variance parameter for PQL2 and MCMC.

Multiple imputation for model checking: completed-data plots with missing and latent data.

In problems with missing or latent data, a standard approach is to first impute the unobserved data, then perform all statistical analyses on the completed dataset--corresponding to the observed data and imputed unobserved data--using standard procedures for complete-data inference. Here, we extend this approach to model checking by demonstrating the advantages of the use of completed-data model diagnostics on imputed completed datasets. The approach is set in the theoretical framework of Bayesian posterior predictive checks (but, as with missing-data imputation, our methods of missing-data model checking can also be interpreted as "predictive inference" in a non-Bayesian context). We consider the graphical diagnostics within this framework. Advantages of the completed-data approach include: (1) One can often check model fit in terms of quantities that are of key substantive interest in a natural way, which is not always possible using observed data alone. (2) In problems with missing data, checks may be devised that do not require to model the missingness or inclusion mechanism; the latter is useful for the analysis of ignorable but unknown data collection mechanisms, such as are often assumed in the analysis of sample surveys and observational studies. (3) In many problems with latent data, it is possible to check qualitative features of the model (for example, independence of two variables) that can be naturally formalized with the help of the latent data. We illustrate with several applied examples.

Every cloud has a silver lining: interpersonal and individual differences determinants of anger-related behaviors.

Two studies examined the effect of status and liking of the anger target on anger behavior and individual differences in anger-related behavior. Participants recalled anger instances in which the anger target was of higher/equal/lower status and/or liked/ unfamiliar/disliked; subsequently, they indicated which behaviors they had displayed. In both studies, anger behaviors could be grouped into behaviors that imply approaching the target (anger-out, assertion, reconciliation) and behaviors that reflect avoidance/anger-in or social sharing. The results demonstrated that approach behaviors more likely occur toward lower status or liked targets; avoidance behaviors and social sharing more likely occur when the target is of higher status or disliked. On an individual differences level, an approach and an avoid/social sharing person class were identified. The findings suggest that anger may motivate prosocial behavior or social sharing, depending on the individual and type of relation with the target. Only few gender differences were found.