Strategic and Automatic Threat Processing in Chronic Musculoskeletal Pain: A Startle Probe Investigation

Attentional bias research with chronic pain samples has yielded conflicting results. In the present investigation the startle paradigm was used to test the postulate that fear‐based mechanisms play an important role in attentional biases for pain‐related threat in chronic pain. Participants, including 31 individuals with chronic musculoskeletal pain and 20 healthy controls, completed a startle task designed to measure attention to different types of words (neutral vs sensory pain vs affective pain vs health catastrophe) presented at different levels of cognitive processing (strategic vs automatic). Measures of fear‐based individual difference variables, including anxiety sensitivity and fear of pain, were also completed. Startle amplitudes and latencies to acoustic startle probes that followed word presentations were recorded. Data were analyzed with repeated measures ANOVAs and correlational analysis. Significant between‐group differences were found indicating that, relative to chronic pain participants, healthy controls had higher startle amplitude index scores for health catastrophe words. There was also a trend among patients with chronic pain for greater startle amplitude index scores for strategic presentations of sensory pain words. In the automatic condition, all participants demonstrated a lower startle latency index for sensory words relative to both affect and health catastrophe words, suggesting participants had more difficulty disengaging from affect and health catastrophe words or were more avoidant of sensory words. Correlational analyses indicated that startle response indices for words related to health catastrophe became more pronounced for chronic pain patients as anxiety sensitivity and fear of pain increased. Implications and directions for future research are discussed.     

海洛因戒治者对疼痛线索的选择性注意加工偏向

研究采用点探测范式,以疼痛线索(感觉疼痛词、情感疼痛词和健康灾难词)和中性线索(中性词)为实验材料,考察接受美沙酮维持治疗的海洛因戒治者对疼痛线索的视觉选择性注意偏向。结果表明:海洛因戒治者对疼痛线索的注意偏向具有普遍性,即对感觉疼痛词、情感疼痛词和健康灾难词等三类疼痛线索均存在注意回避偏向,尤其对健康灾难词的注意回避程度最高;海洛因戒治者还对感觉疼痛词和情感疼痛词存在注意脱离易化倾向。本研究对于有针对性的开展注意偏向矫正以干预疼痛,从而辅助美沙酮的治疗效果、维持患者的戒断状态、降低其复吸风险具有重要意义。     

Automatic processing in spider phobia: implicit fear associations over the course of treatment

This study evaluates the cognitive model of anxiety by investigating treatment-related changes in automatic associations to evaluate schematic processing. Spider-phobic participants (n = 31) and healthy controls (n = 30) completed fear-based Implicit Association Tests (IATs), which are reaction-time measures that tap implicit associations without requiring conscious introspection. The specific tasks involved classifying pictures of snakes and spiders along with semantic categorizations (good vs.bad, afraid vs. unafraid, danger vs. safety, and disgusting vs. appealing). Phobic individuals were assessed before and after group-based exposure treatment and 2 months later, controls were assessed at matched time points. Results supported clinical applications for implicit fear associations, including prediction of phobic avoidance, and treatment sensitivity of the fear- and disgust-specific automatic associations.     

Reducing chronic anxiety by making the threatening event predictable: An experimental approach

Panic disorder is characterized by both specific, phased fear and generalized, chronic anxiety. Standard extinction procedures are efficient in reducing specific fear. However, methods based on human conditioning research - that are capable of reducing chronic anxiety have not yet been thoroughly investigated. This study evaluates a new way of reducing chronic anxiety by signaling aversive events (or by making them more predictable). Using an experimental approach with healthy participants, specific fear and chronic anxiety were operationalized in a within-subjects fear-potentiated startle paradigm by, respectively, conditioning to a cue by presenting predictable shocks and conditioning to a context induced by unpredictable shocks. The results clearly demonstrate that context conditioning is reduced when a discrete cue is added that predicts the onset of the aversive event. The data suggest that making unpredictable events, such as for example panic attacks, predictable, may reduce the generalized and sustained anxiety that often complicates exposure treatment.     

Neural substrates of individual differences in human fear learning: Evidence from concurrent fMRI, fear-potentiated startle, and US-expectancy data

To provide insight into individual differences in fear learning, we examined the emotional and cognitive expressions of discriminative fear conditioning in direct relation to its neural substrates. Contrary to previous behavioral-neural (fMRI) research on fear learning--in which the emotional expression of fear was generally indexed by skin conductance--we used fear-potentiated startle, a more reliable and specific index of fear. While we obtained concurrent fear-potentiated startle, neuroimaging (fMRI), and US-expectancy data, healthy participants underwent a fear-conditioning paradigm in which one of two conditioned stimuli (CS(+) but not CS(-)) was paired with a shock (unconditioned stimulus [US]). Fear learning was evident from the differential expressions of fear (CS(+) > CS(-)) at both the behavioral level (startle potentiation and US expectancy) and the neural level (in amygdala, anterior cingulate cortex, hippocampus, and insula). We examined individual differences in discriminative fear conditioning by classifying participants (as conditionable vs. unconditionable) according to whether they showed successful differential startle potentiation. This revealed that the individual differences in the emotional expression of discriminative fear learning (startle potentiation) were reflected in differential amygdala activation, regardless of the cognitive expression of fear learning (CS-US contingency or hippocampal activation). Our study provides the first evidence for the potential of examining startle potentiation in concurrent fMRI research on fear learning.     

The relationship between anxiety sensitivity and fear of pain in healthy adolescents

The present study investigated the relationship between anxiety sensitivity and fear of pain in a large group of healthy adolescents (N=200). Participants completed the childhood anxiety sensitivity index for children-revised, a questionnaire measuring four specific domains of anxiety sensitivity: fear of cardiovascular symptoms, fear of respiratory symptoms, fear of cognitive dyscontrol, and fear of publicly observable anxiety symptoms, and a simplified version of the pain anxiety symptoms scale, a self-report instrument assessing pain-related anxiety and avoidance (i.e. fear of pain). In line with previous research in adult populations, it was found that anxiety sensitivity is substantially and positively related to fear of pain. Even when controlling for other potential predictors of fear of pain (i.e. pain symptoms, other somatization symptoms, trait anxiety, and panic disorder symptoms), anxiety sensitivity appeared to declare a unique proportion of the variance in pain anxiety symptoms.     

Attention modification in persons with fibromyalgia: a double blind, randomized clinical trial

Contemporary models of chronic musculoskeletal pain emphasize the critical roles of fear, anxiety, and avoidance as well as biases in attention in the development and maintenance of chronic pain disability. Evidence supports the influence of individual difference variables such as anxiety sensitivity, pain-related anxiety, and catastrophizing on the pain experience and on pain-related attentional biases. Changes in attentional biases have been associated with treatment gains in patients with clinically significant anxiety. The Attentional Modification Paradigm (AMP) is a modification of the dot-probe paradigm used to facilitate such changes in attentional biases. Given the relationship between chronic musculoskeletal pain and anxiety, AMP may be effective in reducing pain as well. Participants included persons (n = 17) with fibromyalgia and were randomly assigned to either an AMP condition or a control condition. The participants completed two 15-minute AMP sessions per week for 4 weeks. Those in the AMP condition reported statistically significant and substantial reductions on several individual difference variables relative to those in the control condition, and a greater proportion experienced clinically significant reductions in pain. These preliminary results offer a promising new avenue for treating chronic musculoskeletal pain that warrants additional research. Comprehensive results, limitations, and future directions are discussed.     

Trait anxiety modulates supraliminal and subliminal threat: Brain potential evidence for early and late processing influences

Analysis of threat is thought to involve a “quick and dirty” stage in conjunction with slower processing that is more complete. We investigated both types of threat analysis by recording brain potentials in response to threat and neutral words. Personality testing was used to identify participants who were either high or low in trait anxiety (TA). An observed enhancement of occipital P1 potentials to threat words during an emotional Stroop task was interpreted as a signal of unconscious processing, since it was early, independent of whether word exposure was subliminal or supraliminal, and more prominent the higher the level of TA. Later positive potentials were also enhanced for threat versus neutral words, but the amplitude enhancement increased with higher TA only in the subliminal condition. These results suggest that unconscious analysis of threat is intensified in those prone to anxiety, as is a later stage of threat processing subject to dynamic interactions between automatic and strategic influences.     

Attention Modification in Persons with Fibromyalgia: A Double Blind,Randomized Clinical Trial

Contemporary models of chronic musculoskeletal pain emphasize the critical roles of fear, anxiety, and avoidance as well as biases in attention in the development and maintenance of chronic pain disability. Evidence supports the influence of individual difference variables such as anxiety sensitivity, pain-related anxiety, and catastrophizing on the pain experience and on pain-related attentional biases. Changes in attentional biases have been associated with treatment gains in patients with clinically significant anxiety. The Attentional Modification Paradigm (AMP) is a modification of the dot-probe paradigm used to facilitate such changes in attentional biases. Given the relationship between chronic musculoskeletal pain and anxiety, AMP may be effective in reducing pain as well. Participants included persons (n = 17) with fibromyalgia and were randomly assigned to either an AMP condition or a control condition. The participants completed two 15-minute AMP sessions per week for 4 weeks. Those in the AMP condition reported statistically significant and substantial reductions on several individual difference variables relative to those in the control condition, and a greater proportion experienced clinically significant reductions in pain. These preliminary results offer a promising new avenue for treating chronic musculoskeletal pain that warrants additional research. Comprehensive results, limitations, and future directions are discussed.     

Anger management style and emotional reactivity to noxious stimuli among chronic pain patients and healthy controls: the role of endogenous opioids.

OBJECTIVE: Previous work suggests that elevated trait anger-out exacerbates pain responses in part through endogenous opioid dysfunction. The authors examined whether this opioid dysfunction affects not only perceived pain intensity, but also emotional responses to being hurt. DESIGN: 79 chronic low back pain (LBP) patients and 46 healthy controls received opioid blockade (8 mg naloxone i.v.) and placebo in randomized, counterbalanced order in separate sessions. During each session, participants sequentially experienced finger pressure pain and ischemic forearm pain tasks, with emotional state assessed at baseline and postpain. MAIN OUTCOME MEASURES: Blockade effects indexing opioid modulation of emotional reactivity were derived by subtracting placebo from blockade condition emotional reactivity. RESULTS: Significant Participant Type x Anger-Out interactions on blockade effects indicated that in LBP participants but not in controls, greater anger-out was associated with deficient opioid modulation of anxiety, anger, and fear reactivity to noxious stimulation. Across participant types, greater anger-in was associated with impaired opioid modulation of anxiety and fear reactivity. Anger-in opioid effects were partially due to overlap with general negative affect. CONCLUSIONS: Opioid dysfunction associated with trait anger-out may affect not only perceived pain intensity, but also pain-related suffering in individuals with chronic pain conditions. Implications for understanding the health effects of anger management styles are discussed.     

Health anxiety moderates the effects of distraction versus attention to pain

Little is known about the relationship between health anxiety and chronic pain. The present study explored whether individual differences in health anxiety would influence the response of chronic pain patients to physical therapy. Furthermore, the interaction of health anxiety with coping strategy usage (distraction versus attention) was studied. Participants were 81 chronic pain patients who were interviewed and completed measures of pain, anxiety and cognition following an active physiotherapy session in which they either: (1) attended to physical sensations; (2) distracted from physical sensations or (3) completed the session as usual. Health anxious, compared to non-health anxious, individuals worried more about their health and injury during the session and attended to and catastrophically misinterpreted sensations more frequently. A complex interaction between health anxiety and coping strategy emerged. Among health anxious patients, attention to sensations resulted in lower anxiety and pain than did distraction. It appears as though attention had a short-term anxiety reducing effect for health anxious patients. Among non-health anxious patients, attention resulted in greater worry about health than distraction. Clinical and theoretical implications are discussed.     

Pain anxiety among chronic pain patients: specific phobia or manifestation of anxiety sensitivity?

Rather than viewing anxiety among chronic pain patients as simply a component of negative affectivity, investigators have developed a model of "pain anxiety" in which patients develop fear and avoidance of activity linked to pain. We examined whether pain anxiety can be conceptualized as a specific phobia, or whether evidence supported the notion that pain anxiety is better understood as a manifestation of anxiety sensitivity in the context of chronic pain. Chronic musculoskeletal pain patients (N=70) underwent cold pressor and mental arithmetic tasks while cardiovascular, self-report, and behavior indexes were recorded. They completed measures of pain anxiety, anxiety sensitivity, fear of negative evaluation, depression and trait anxiety. Correlation analyses showed pain anxiety was related to pain-relevant responses during cold pressor, but it was also related to evaluation-relevant responses during cold pressor, and to pain- and evaluation-relevant responses (including subtraction accuracy) during mental arithmetic. Regression analyses showed that almost all effects of pain anxiety on task responses were accounted for by anxiety sensitivity. Fear of negative evaluation, in contrast, correlated only with evaluation-relevant responses, and mostly during mental arithmetic. These effects remained significant when depression, trait anxiety, or anxiety sensitivity were statistically controlled. Pain anxiety may be an expression of anxiety sensitivity rather than a circumscribed phobia; a distinction that could profitably guide treatment strategies.     

Anxiety sensitivity and fear of pain in patients with recurring headaches.

Anxiety sensitivity (AS) plays an important role in the cognitive, affective and behavioral profiles of patients with chronic pain related to musculoskeletal injury. However, investigators have not considered whether these findings extend to patients with other classes of chronic pain. The primary purpose of this investigation was to address this issue in 72 patients with recurring headaches who completed a self-report questionnaire inventory during a treatment visit to an outpatient neurology clinic. The mean ASI score for the group (mean = 24; SD = 11) was relatively high. When patients were classified on the basis of ASI scores, 20 (28%) met criteria for high, 41 (57%) for medium and 11 (15%) for low AS. Multivariate analysis of variance confirmed that these groups differed on specific aspects of their cognitive, affective, and behavioral profiles. High AS patients reported greater depression, trait anxiety, pain-related escape/avoidance behavior and fearful appraisals of pain than did patients with medium or low AS. High AS patients also indicated greater cognitive disruption in response to pain than did patients with low AS. Groups did not differ in headache severity, physiological reactivity, change in lifestyle, anger, nor did they differ in use of over-the-counter or prescribed analgesics. Multiple regression analysis identified AS, pain-related cognitive disruption, and sensory pain experience as significant predictors of fear of pain. Lifestyle changes attributed to headache were, on the other hand, predicted by headache severity, physiological and cognitive anxiety and escape/avoidance behavior. These results provide further evidence of the important association between AS and fear responses of patients with chronic pain syndromes. Implications and future directions are discussed.     

Measuring anxious responses to predictable and unpredictable threat in children and adolescents

Research has highlighted the need for new methods to assess emotions in children on multiple levels to gain better insight into the complex processes of emotional development. The startle reflex is a unique translational tool that has been used to study physiological processes during fear and anxiety in rodents and in human participants. However, it has been challenging to implement developmentally appropriate startle experiments in children. This article describes a procedure that uses predictable and unpredictable aversive events to distinguish between phasic fear and sustained anxiety in children and adolescents. We investigated anxious responses, as measured with the startle reflex, in youths (N = 36, mean age = 12.63 years, range = 7-17) across three conditions: no aversive events (N), predictable aversive events (P), and unpredictable aversive events (U). Short-duration cues were presented several times in each condition. Aversive events were signaled by the cues in the P condition but were presented randomly in the U condition. Participants showed fear-potentiated startle to the threat cue in the P condition. Startle responses were also elevated between cues in the U condition compared with the N condition, suggesting that unpredictable aversive events can evoke a sustained state of anxiety in youths. This latter effect was influenced by sex, being greater in girls than in boys. These findings indicate the feasibility of this experimental induction of the startle reflex in response to predictable and unpredictable events in children and adolescents, enabling future research on interindividual differences in fear and anxiety and their development in youths.     

Individual differences in self-assessed health: an information-processing investigation of health and illness cognition.

In 2 studies, the relation between measures of self-assessed health (SAH) and automatic processing of health-relevant information was investigated. In Study 1, 84 male and 86 female undergraduate students completed a modified Stroop task. Results indicated that participants with poorer SAH showed enhanced interference effects for illness versus non-illness words. In Study 2, 27 male and 30 female undergraduate students completed a self-referent encoding task. Results offered a conceptual replication and extension of Study 1 by confirming the specificity of the relation between SAH measures and automatic processing of health (vs. negative or positive general trait) information. These studies provide evidence that individual differences in SAH are reflected in schematic processing of health-relevant information.     

The costs of caring: Gender identification increases threat following exposure to sexism

The current research examined whether group identification moderates the extent to which perceived ingroup discrimination is threatening, as indexed by physiological and self-report measures. Women read and gave a speech summarizing an article describing sexism as prevalent or rare. They then completed a distraction task and sat for a recovery period. Cardiovascular reactivity (CVR) was used to index threat experienced on an automatic level and self-reported anxiety was used to index threat experienced on a controlled level. Regardless of group identification, participants in the prevalent sexism (vs. rare sexism) condition exhibited a pattern of CVR consistent with threat during the speech and reported greater anxiety post-speech. During recovery, however, highly identified participants in the prevalent sexism condition exhibited a sustained threat pattern of CVR and reported higher anxiety post-recovery compared to low identifiers. High group identification may heighten the psychological and physiological burden of discrimination.     

Trait Anxiety and Fear Responses to Safety Cues: Stimulus Generalization or Sensitization?

Abnormal fear responding to threat cues may contribute to the aetiology and maintenance of persistent fears and pathological anxiety. Chronic anxiety may also involve abnormal fear responding to ??safety?? cues, which do not signal danger. Yet investigations of fear responding to acquired safety cues are scarce and the basis of such responding remains unclear. Moreover, previous studies do not distinguish between stimulus generalization (an associative mechanism based on perceptual similarity between threat and safety cues) and sensitization (a non-associative mechanism whereby fear responses to any novel, intense, or fear-related stimulus are temporarily elevated). This study investigated responses to acquired safety cues in volunteers with varying trait anxiety, using a novel fear conditioning paradigm designed to distinguish between effects of trait anxiety on generalization and sensitization. The paradigm used three conditioned stimuli: a threat cue (CS+) and two safety cues (CS?), one perceptually similar to the CS+ and one perceptually dissimilar. Conditioned fear to these cues was indexed by fear potentiation of the startle blink reflex, skin conductance responses, and self-report. To examine how trait anxiety moderated responses to safety cues, participants were divided into high and low trait anxiety subgroups. Startle, skin conductance, and self-reported fear measures indicated that generalization of fear occurred for the safety cue which resembled the threat cue, but not for the perceptually dissimilar safety cue, consistent with the stimulus generalization hypothesis. There was some evidence that stimulus generalization was exaggerated in anxious individuals. The current study sheds light on the mechanism by which fear responses to safety cues arise in healthy individuals, and offers some insight into the influence of this mechanism in chronic anxiety.     

Differences in high and low anxiety sensitive women's responses to a laboratory-based cold pressor task

Anxiety sensitivity (AS) has been linked to a variety of disabling chronic health conditions, including pain-related conditions. A recent study has found that healthy women with high AS reported significantly higher levels of sensory and affective pain on an experimental cold pressor task compared to women with low AS. However, this study found no differences between AS groups for pain tolerance or pain threshold. In the present study, which was designed to replicate and extend these findings, 90 undergraduate university women were selected for inclusion in 1 of 2 AS groups (high or low) based on their screening scores on a 16-item measure of AS. Participants were tested individually on a lab-based cold pressor task using a variety of self-report and observer-measured variables. Data analyses revealed that, as expected, the high AS participants reported significantly more fear in response to the cold pressor on a relevant item of the McGill Pain Questionnaire-Short Form (SF-MPQ) than did the low AS participants. Also as expected, the high AS participants reported more pain in response to the cold pressor on the Present Pain Index (PPI) of the SF-MPQ than did the low AS participants. High AS participants did not differ from low AS participants on other aspects of the cold pressor response (e.g. pain threshold, pain tolerance, pain recovery). These results support the role of pain-related fear as a mediating variable between AS and increased perceived pain intensity.     

Increased use of safety-seeking behaviors in chronic back pain patients with high health anxiety

Many patients with chronic pain also exhibit elevated levels of health anxiety. This study examined the effect of health anxiety on the use of safety-seeking behaviors (SSBs) in pain-provoking situations. Participants were 20 chronic back pain patients with high health anxiety (Group H), 20 with low health anxiety (Group L) and 20 pain-free controls (Group C). Two physical tasks were video recorded, and compared both for overt pain behavior (identified by blind observers following a standardized procedure) and for the occurrence of SSB (identified by showing the participants video playback and asking them to specify motivation for all actions/behaviors displayed during the tasks). While there were no differences in the display of overt pain behaviors, Group H deployed a greater number of SSBs than Groups L and C. This finding held true for both tasks and remained significant when concurrent pain and mood ratings were statistically controlled for. SSB was correlated with catastrophizing thoughts but not pain intensity; pain intensity was correlated with overt pain behavior but not catastrophizing. Taken together, these findings suggest that SSB is distinct from overt pain behavior and may be a defining characteristic of chronic pain patients reporting high levels of health anxiety.