Behavioral Test (BAT-Back): Preliminary Evidence for a Successful Predictor of Treatment Outcome After Exposure Treatment for Chronic Low Back Pain.

OBJECTIVES: Although several questionnaires assessing fear of movement exist, it is still a challenge to identify individuals who might benefit more from exposure for chronic pain than from other psychological approaches and vice versa. Psychological approaches to chronic pain cannot advance toward the often called-for "tailored approaches" because of limited knowledge about treatment predictors. Our aim was to evaluate the additional predictive value of avoidance behavior based on behavioral observation. METHODS: This study examined pretreatment self-report and behavioral measures as predictors of treatment outcome for n=43 patients experiencing disabling chronic low back pain, who took part in a randomized controlled trial in which they received 10 to 15 sessions of exposure treatment. Only patients with elevated fear avoidance based on self-report measures were included. Data were analyzed using regression analyses and classification and regression trees. RESULTS: Regression analyses showed that higher avoidance behavior at pretreatment as measured by the Behavioral Avoidance Test-Back Pain (BAT-Back) significantly predicted reduction in global disability (with a small to medium effect), but not in specific disability. Self-report measures failed to predict treatment success for both outcome measures. Classification and regression trees divide subgroups who might benefit from exposure treatment through a BAT-Back score of >22 for Pain Disability Index. DISCUSSION: There is some preliminary evidence that pretreatment avoidance behavior might be an indicator for reduction in global disability after exposure treatments in patients experiencing disabling chronic low back pain and elevated fear avoidance. We identified preliminary cutoff scores that need further investigation.

Dechloromonas and close relatives prevail during hydrogenotrophic denitrification in stimulated microcosms with oxic aquifer material.

Globally occurring nitrate pollution in groundwater is harming the environment and human health. In situ hydrogen addition to stimulate denitrification has been proposed as a remediation strategy. However, observed nitrite accumulation and incomplete denitrification are severe drawbacks that possibly stem from the specific microbial community composition. We set up a microcosm experiment comprising sediment and groundwater from a nitrate polluted oxic oligotrophic aquifer. After the microcosms were sparged with hydrogen gas, samples were taken regularly within 122 h for nitrate and nitrite measurements, community composition analysis via 16S rRNA gene amplicon sequencing and gene and transcript quantification via qPCR of reductase genes essential for complete denitrification. The highest nitrate reduction rates and greatest increase in bacterial abundance coincided with a 15.3-fold increase in relative abundance of Rhodocyclaceae, specifically six ASVs that are closely related to the genus Dechloromonas. The denitrification reductase genes napA, nirS and clade I nosZ also increased significantly over the observation period. We conclude that taxa of the genus Dechloromonas are the prevailing hydrogenotrophic denitrifiers in this nitrate polluted aquifer and the ability of hydrogenotrophic denitrification under the given conditions is species-specific.

Exposure and CBT for chronic back pain: An RCT on differential efficacy and optimal length of treatment.

OBJECTIVE: Our aim was to establish whether Exposure, a specialized tailored treatment for chronic low back pain, has any advantages over cognitive-behavioral therapy (CBT) among individuals with high fear-avoidance levels. Second, we planned to compare short and long versions of Exposure. Third, we aimed to investigate whether Exposure can be delivered in an outpatient psychological setting. METHOD: A total of 88 Caucasian participants (55% women) were randomized to three different psychological treatment conditions, Exposure-long, Exposure-short, and CBT. All participants were suffering from chronic pain and elevated levels of pain-related anxiety and disability. The primary outcomes were disability (assessed using two different questionnaires, QBPDS and PDI) and average pain intensity; secondary outcomes included pain-related anxiety, psychological flexibility, coping strategies, and depression. Assessments took place at pretreatment, midtreatment, posttreatment, and 6-month follow-up. RESULTS: Exposure was more effective than CBT at reducing movement-related disability assessed with the QBPDS. Exposure and CBT did not differ in reduction of pain intensity or disability assessed using the PDI. Exposure-short outperformed Exposure-long after 10 sessions, meaning that individuals improved faster when they were offered fewer sessions. Exposure could be safely delivered in the psychological setting. Concerning secondary outcomes, Exposure led to greater improvements in psychological flexibility relative to CBT. CBT was more effective than Exposure at enhancing coping strategies. In Exposure, significantly more participants dropped out. CONCLUSIONS: Although being more challenging to patients, Exposure is an effective treatment, which can be delivered in a psychological treatment setting and should be offered as a short-term treatment. (PsycINFO Database Record

Cross-cultural adaption of the German Quebec Back Pain Disability Scale: an exposure-specific measurement for back pain patients.

STUDY DESIGN: Cross-cultural translation and psychometric testing. OBJECTIVE: The purpose of the present study was to examine reliability and validity of a cross-cultural adaption of the German Quebec Back Pain Disability Scale (QBPDS) in a context of a randomized controlled trial evaluating the effectiveness of graded in vivo exposure in chronic low back pain patients. BACKGROUND: The QBPDS is one of the most widely used disease-specific disability questionnaires. In particular, for cognitive behavioral treatments with a clear focus on behavioral aspects such as graded in vivo exposure, the QBPDS provides an ascertained strategy with a sound conceptual basis and excellent quality criteria. Nevertheless, there is conflicting evidence concerning factor structure and a German adaption is missing. METHODS: The cross-cultural adaption followed international guidelines. Psychometric testing was performed using data from 180 participants with chronic low back pain. The psychometric analyses included internal consistency, convergent, and divergent validity. Exploratory factor analysis was used to determine the underlying factor structure. RESULTS: The QBPDS showed strong psychometric properties, with high internal consistency for the full scale (α=0.94) and good convergent and divergent validity. The factor analysis revealed a four-factor solution (bending, ambulation, brief effortful movements, and long-lasting postures). CONCLUSION: The translation and cross-cultural adaption of the QBPDS into German was successful. The German version proved to be a valid and reliable instrument and is well suited for use in the context of an exposure-based psychological treatment.

Development and Validation of the Behavioral Avoidance Test-Back Pain (BAT-Back) for Patients With Chronic Low Back Pain.

OBJECTIVES: Pain-related fear and avoidance of physical activities are central elements of the fear-avoidance model of musculoskeletal pain. Pain-related fear has typically been measured by self-report instruments. In this study, we developed and validated a Behavioral Avoidance Test (BAT) for chronic low back pain (CLBP) patients with the aim of assessing pain-related avoidance behavior by direct observation. MATERIALS AND METHODS: The BAT-Back was administered to a group of CLBP patients (N=97) and pain-free controls (N=31). Furthermore, pain, pain-related fear, disability, catastrophizing, and avoidance behavior were measured using self-report instruments. Reliability was assessed with intraclass correlation coefficient and Cronbach α. Validity was assessed by examining correlation and regression analysis. RESULTS: The intraclass correlation coefficient for the BAT-Back avoidance score was r=0.76. Internal consistency was α=0.95. CLBP patients and controls differed significantly on BAT-Back avoidance scores as well as self-report measures. BAT-Back avoidance scores were significantly correlated with scores on each of the self-report measures (rs=0.27 to 0.54). They were not significantly correlated with general anxiety and depression, age, body mass index, and pain duration. The BAT-Back avoidance score was able to capture unique variance in disability after controlling for other variables (eg, pain intensity and pain-related fear). DISCUSSION: Results indicate that the BAT-Back is a reliable and valid measure of pain-related avoidance behavior. It may be useful for clinicians in tailoring treatments for chronic pain as well as an outcome measure for exposure treatments.

Do patients with chronic pain show autonomic arousal when confronted with feared movements? An experimental investigation of the fear-avoidance model.

The relevance of a phobia-based conceptualization of fear for individuals with chronic pain has been much debated in the literature. This study investigated whether patients with highly fearful chronic low back pain show distinct physiological reaction patterns compared with less fearful patients when anticipating aversive back pain-related movements. We used an idiosyncratic fear induction paradigm and collected 2 different measures of autonomic nervous system activation and muscle tension in the lower back. We identified 2 distinct psychophysiological response patterns. One pattern was characterized by a moderate increase in skin conductance, interbeat interval (IBI) increase, and muscle tension increase in the lower back. This response was interpreted as an attention reaction to a moderately stressful event. The other pattern, found in 58% of the participants, was characterized by a higher skin conductance response, IBI decrease, and muscle tension increase in the lower back. According to Bradley and Lang defense cascade model, this response is typical of a fear reaction. Participants showing the psychophysiological pattern typical of fear also had elevated scores on some self-report measures of components of the fear-avoidance model, relative to participants showing the reaction pattern characteristic of attention. This study is the first to provide psychophysiological evidence for the fear-avoidance model of chronic pain.

Evaluation and implementation of graded in vivo exposure for chronic low back pain in a German outpatient setting: a study protocol of a randomized controlled trial.

BACKGROUND: The purpose of the present study is to introduce an adapted protocol of in vivo exposure for fear avoidant back pain patients and its implementation in the German health care system without multidisciplinary teams. Case studies demonstrated promising effects but three preceding randomized controlled trials (RCTs) could not support the former results. More empirical support is necessary to further substantiate the effectiveness of in vivo exposure. METHODS: A total of 108 chronic low back pain patients are randomly assigned to one out of three conditions (A: exposure_long (15 sessions), B: exposure_short (10 sessions) or C: control condition cognitive behavioral therapy (15 sessions)). The inclusion criteria are: back pain ≥3 months and a sufficient level of fear-avoidance. An effect evaluation, a process evaluation and an economic evaluation are conducted. Primary outcomes are pain-related disability and pain intensity. Secondary outcomes are: emotional distress, fear avoidance, catastrophizing and costs. Data are collected at baseline, upon completion of the intervention, after 10 sessions, and at six months following completion of treatment. Besides the comparison of exposure in vivo and cognitive behavioral therapy (CBT), we additionally compare a short and a long version of exposure to analyze dose response effects. DISCUSSION: This is, to our knowledge, the first RCT comparing in vivo exposure to psychological treatment as usual in terms of cognitive behavioral therapy. Results will help to find out whether a tailored treatment for fear avoidant back pain patients is more effective than a general pain management treatment. TRIAL REGISTRATION: The trial has been registered to ClinicalTrial.gov. The trial registration number is NCT01484418.