Fear avoidance beliefs in back pain-free subjects are reflected by amygdala-cingulate responses.

Michael L Meier,Sabina Hotz-Boendermaker,Barry K Humphreys,Erich Seifritz,Andrea Vrana,Phillipp Stämpfli

doi:10.3389/fnhum.2015.00424

Abstract

In most individuals suffering from chronic low back pain, psychosocial factors, specifically fear avoidance beliefs (FABs), play central roles in the absence of identifiable organic pathology. On a neurobiological level, encouraging research has shown brain system correlates of somatic and psychological factors during the transition from (sub) acute to chronic low back pain. The characterization of brain imaging signatures in pain-free individuals before any injury will be of high importance regarding the identification of relevant networks for low back pain (LBP) vulnerability. Fear-avoidance beliefs serve as strong predictors of disability and chronification in LBP and current research indicates that back pain related FABs already exist in the general and pain-free population. Therefore, we aimed at investigating possible differential neural functioning between high- and low fear-avoidant individuals in the general population using functional magnetic resonance imaging. Results revealed that pain-free individuals without a history of chronic pain episodes could be differentiated in amygdala activity and connectivity to the pregenual anterior cingulate cortex by their level of back pain related FABs. These results shed new light on brain networks underlying psychological factors that may become relevant for enhanced disability in a future LBP episode.

Highlights

Acute low back pain (LBP) has a favorable prognosis; most patients recover within 6 weeks (Koes et al, 2001)
The categorical whole-brain analysis of the contrast “harmful activities > harmless activities” yielded significant bilateral amygdala activity in the TSK-Ghigh group, whereas no amygdala activity was observed in the TSK-Glow group
Specific psychological processes and underlying brain networks may be involved in conferring vulnerability to painful conditions that likely contribute to some of these discrepancies (Denk et al, 2014; Simons et al, 2014a).The most consistent finding is the strong predictive power of fear avoidance beliefs (FABs) and pain-related fear for perceived disability in chronic pain (Vlaeyen et al, 1995a,b; Cook et al, 2006)

Summary

Introduction

Acute low back pain (LBP) has a favorable prognosis; most patients recover within 6 weeks (Koes et al, 2001). In the development of chronic disability and in the absence of identifiable organic pathology, psychosocial variables, fear avoidance beliefs (FABs), have been recognized as significant prognostic factors (Vlaeyen and Linton, 2000; Buchbinder et al, 2001; Buer and Linton, 2002; Leeuw et al, 2007b; Chou and Shekelle, 2010; Wertli et al, 2013) Such fears are represented by a subjectively misinterpreted importance of back pain and an associated vulnerability of the spine and can lead to avoidance behavior due to fear that certain behaviors will worsen the pain. At the stage of chronic LBP, these brain changes can show discriminative power leading to the ability to distinguish between individuals with and without chronic LBP on a neural level (Callan et al, 2014; Ung et al, 2014)

Methods

Results

Conclusion