The Fear-Avoidance Model moves forward

New research from the ‘7th World Congress on Behavioural and Cognitive Therapies’

Cognitive and behavioural therapy (CBT) is the most widely researched and used approach in psychology. A recent review of 108 meta-analyses showed that, when compared to other treatments (for psychological problems), CBT generally proves to be equally or more effective regardless of the condition[1] – though it’s best with anxiety disorders. Where chronic pain is concerned, benefits are in the small to medium range with the greatest effects on disability and distress. Surprisingly, despite the magnitude of the pain problem and the large scale of this congress, the word ‘chronic pain’ would have barely been uttered if not for the small group of outstanding scientists depicted above.

Petra Karsdorp, Stéphanie Volders, Ann Meulders, Judy Veldhuijzen

Petra Karsdorp, Stéphanie Volders, Ann Meulders, Judy Veldhuijzen

In their packed out session, Dr Ann Meulders (second from right) led the discussion on fear, motivational goals and attention as mediators of pain, disability and suffering. Underpinning these presentations were the theoretical assumptions of the fear-avoidance model (FAM) – with each presentation confirming that those closest to the model are also the most aware of its insufficiencies and the most intent on testing its assumptions and extending its boundaries (for a blog about the FAM see Neil O’Connell‘s or Lorimer Moseley‘s blog post).

Dr Ann Meulders opened by pointing out that the FAM relies on the idea that after an injury, movements associated with pain, become initiators of conditioned fear responses (see blog post on classical conditioning and pain). As the FAM then stipulates, these fear responses (under certain conditions) drive hypervigilance and avoidance behaviour resulting in disuse, disability and distress (you know the cycle!). The conundrum here is that if movement (the conditioned initiator of fear) is avoided, then there should be no conditioned fear responses – leaving the relationship between fear and avoidance unexplained. Ann used a neat experimental design where particular movements of a joystick are paired with a painful shock (to induce movement-related fear), to show that after this pairing, increases in fear were present on the intention to move (as measured via a fear modulated reflex – ‘the startle response’)[2]. Thus the thought of/intention to move might be a covert initiator of pain-related fear and provide the link between fear and avoidance. Conundrum solved!?

Dr Petra Karsdorp (far left) followed this by pointing out that pain-related fear has only a small to moderate relationship with the development of pain-related disability, leaving the cause of avoidance largely unexplained. She proposed that another factor might be one’s ability to resist/inhibit automatic withdrawal responses in favour of other goals. To test this theory, Petra measured subject’s ability to inhibit automatic responses using a test called the ‘stop signal test’ (which you can read about in her paper[3]). She then asked subjects to hold their hand in icy water and promised cash for persisting. Here the automatic pain-related withdrawal response was competing with the motivational goal of earning money. She then tested whether subjects ability to inhibit automatic responses (stop signal test score), predicted withdrawal of a hand from icy water. Whilst pain-related fear did not relate to quicker withdrawal, low score on the response inhibition task did. This raises the possibility that during a painful event, one’s capacity to inhibit automatic withdrawal responses, might contribute to the avoidance-related cycle. Early management might therefore benefit from enhancing focus on motivational goals and improving automatic response inhibition.

Dr Judy Veldhuijzen (far right) discussed the prioritisation of pain-related information (attentional bias) and associated clinical phenomena such as hyper-vigilance and impaired cognitive performance. Whereas the FAM proposes that pain-related fear drives this shifting of attention, meta-analyses have shown this not to be the case [4]. Judy then proposed that if these attentional biases are not related to fear, then fear-based treatments are unlikely to assist this component of the problem. Rather, targeting attentional processes directly might better treat hyper-vigilance toward pain-related cues. She offered ideas here including an approach called ‘attentional bias modification’ to address implicit attentional biases, and altering cognitions to address more explicit biases.

Finally Dr Stéphanie Volders (second from left) discussed her research investigating why pain-related fear (and associated problems) might return after its successful treatment using exposure therapy (the model treatment for pain-related fear). Specifically she examined whether the things people do to feel safe in the short term (known as ‘safety behaviours), such as wear a back brace, might actually prevent successfully treatment. Using a laboratory study of healthy subjects, Stéphanie induced fear of movement by pairing a joystick movement with a painful shock [5]. She then split the subjects into two groups. In one group subjects performed the same task without the painful shock (an analogy to exposure therapy which reduces fear by disconfirming the relationship between movement and harm) while those in the other group performed the same procedure except that participants were given the opportunity to press a button they were told would enable them to avert the shock (but which actually did nothing). In both conditions self-report data confirmed that fear of movement had been successfully extinguished. This phase was then repeated with neither group having the button. In the group that previously had the button, the fear of movement returned. Here it seems that even though the button did nothing, subjects attributed their safety to it. This she proposed was a clinical parallel for patients who might improve greatly in the short term, but attribute safety to the presence of the therapist, the walking stick, or the back brace and thus fail to make persistent gains in pain-related fear.

It seems that even 30 years on since it was proposed, and with all of its inadequacies, the FAM continues to be a catalyst for ideas for those who would look past its superficial exterior. Perhaps with important contributions such as these it is time for a new model.

Stay tuned for the next post on pain-related fear from Ann Meulders.

Daniel Harvie

Daniel Harvie BodyInMind

Daniel is a PhD candidate in the Body in Mind Research Group at UniSA. He has a clinical physiotherapy background and is a graduate of the Master of Musculoskeletal and Sports degree at The University of South Australia. His research uses a classical conditioning (associative learning) paradigm to look at the transference of injury related responses to previously meaningless stimuli.

He is currently in Belgium undertaking research with the likes of Ann Meulders and Johan Vlaeyen (best known for their fear-avoidance related research). He enjoys writing and recording music  and has a bionic knee.

References

[1] Hofmann SG, Asnaani A, Vonk IJ, Sawyer AT, & Fang A (2012). The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses. Cognitive therapy and research, 36 (5), 427-440 PMID: 23459093

[2] Meulders A, & Vlaeyen JW (2013). Mere intention to perform painful movements elicits fear of movement-related pain: an experimental study on fear acquisition beyond actual movements. J Pain, 14 (4), 412-23 PMID: 23453562

[3] Karsdorp PA, Geenen R, & Vlaeyen JW (2013). Response inhibition predicts painful task duration and performance in healthy individuals performing a cold pressor task in a motivational context. Eur J Pain PMID: 23788405

[4] Crombez G, Van Ryckeghem DM, Eccleston C, & Van Damme S (2013). Attentional bias to pain-related information: a meta-analysis. Pain, 154 (4), 497-510 PMID: 23333054

[5] Volders S, Meulders A, De Peuter S, Vervliet B, & Vlaeyen JW (2012). Safety behavior can hamper the extinction of fear of movement-related pain: an experimental investigation in healthy participants. Behaviour research and therapy, 50 (11), 735-46 PMID: 23000846