Evaluating the novel added value of neurophysiological pain sensitivity within the fear‐avoidance model of pain

Abstract

Background The fear‐avoidance model (FAM) is a leading theoretical paradigm for explaining persistent pain following musculoskeletal injury. The model suggests that as injuries heal, pain‐related outcomes are increasingly determined by psychological, rather than physiological factors. Increasing literature, however, suggests that neurophysiological processes related to pain sensitivity also play an important role in chronicity. To date, there has been limited research that has specifically explored the role of pain sensitivity within the FAM. This study addresses this gap by evaluating whether clinical measures of pain sensitivity help explain FAM‐related outcomes, beyond model‐relevant psychological predictors. Methods The study sample consisted of 80 adults with chronic and widespread musculoskeletal pain. Participants completed a single testing session that included measures of all of the major constructs of the FAM, including pain catastrophizing, pain‐related fear, activity avoidance (self‐report and functional measures), pain‐related disability, depression and pain severity, as well as a battery of quantitative sensory testing that included measures of pressure pain threshold and temporal summation of mechanical pain across eight body sites. Results A series of hierarchical regression analyses revealed that after controlling for the psychological predictors of the FAM, indices of pain sensitivity significantly predicted 4 of the 5 FAM‐related outcomes (p < 0.05). Depression was the only outcome not significantly predicted by pain sensitivity. Interestingly, measures of pain sensitivity, but not FAM psychological factors, predicted the functional measure of activity avoidance. Conclusions These findings provide further evidence for the importance of neurophysiological factors within the FAM and have important clinical and theoretical implications. Significance This study provides evidence for the unique and added value of neurophysiological factors within the Fear Avoidance Model of pain and for the importance of integrating both sensory and psychological factors within both theoretical paradigms and clinical management strategies.

<p>Multisensory Sensitivity is Related to Deep-Tissue but Not Cutaneous Pain Sensitivity in Healthy Individuals</p>

“…associated with the fear-avoidance model, such as pain catastrophizing and pain-related disability. 8 This supports the application of QST and its relevance to diverse aspects of the pain experience. As TSP and CPM are widely accepted as measures reflecting central facilitation and inhibition of pain, 6 the associations observed in our study may indicate that noxious and non-noxious sensory processing may be linked centrally, even prior to the onset of a clinical pain syndrome.…”

“…Dynamic and static QST have been widely applied to measure pain sensitivity in clinical pain populations and to further infer the underlying mechanisms. 6,8,[56][57][58] For instance, PPT and TSP to mechanical stimuli have been predictive of factors Figure 3 Boxplots showing median (black bars) and 25th-75th percentiles (IQR boxes) of (A) local pain ratings between men and women from the saline infusion at 80 mL/ hr and (B) pressure pain thresholds (PPT) at the deltoid muscle are shown by sex-specific MSS quartiles. Significant sex-MSS interactions were observed for both conditions; yet the follow-up stratified analyses by sex only show the significant difference on saline infusion at 80 mL/hr in women between MSS quartiles (eg, 4th = highest sensory sensitivity) and the referent MSS quartile (1st, lowest) (*p≤0.05).…”

“…4,5 Because central mechanisms and nociplastic changes cannot be assessed directly in humans, they are typically inferred as greater pain sensitivity using dynamic quantitative sensory testing (QST) relative to healthy individuals. [4][5][6][7][8] More specifically, dynamic QST includes assessment of temporal summation of pain (TSP) and conditioned pain modulation (CPM). TSP refers to a wind-up response of C fibers to repetitive activation in animal models 9 and has been well accepted as a psychophysical measure of net central facilitation of human pain in clinical settings.…”

A Cumulative Impact of Psychological and Sensitization Risk Factors on Pain‐Related Outcomes

“…Specifically, elevated levels of PC contribute to several negative outcomes in clinical pain management, including increased activity avoidance, disability, and pain severity 3,4 . Considerable research helped establish PC as a key predictor of persistent pain and risk factor for clinical pain management 5–9 . PC is also linked to increased attention toward pain‐related stimuli and avoidance of pain‐related activities 10–12 .…”

Pain and Function in Chronic Musculoskeletal Pain—Treating the Whole Person

“…11 Of the different elements that make up this complex biopsychosocial model, the psychological aspect is one of the hardest to overcome, underlining the importance of addressing both the sensory and psychological factors driving chronic pain. [12][13][14] Patients may experience satisfactory improvement in their pain and functional abilities, but still feel depressed and think they will never fully recover from chronic pain (ie, never be completely pain free or restored to their pre-injury level of function). Psychological factors such as fatigue, emotional distress, resistance, and catastrophizing, can increase the level of pain and suffering in those with chronic pain.…”