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Fear of pain, not always fear of harm

Posted Mar 25 2010 10:05pm

I know it’s actually Friday Funnies day, but before I go there I want to explore something I’ve been observing for a while.  Over the past four or five years, the TSK (Tampa Scale for Kinesiophobia) has been a really popular instrument for identifying and monitoring pain-related anxiety and avoidance.  It has been found to have a two-factor structure, ‘harm’ and ‘activity avoidance’, and has been used as both a predictive measure and an outcome measure that is strongly associated with disability.

What I’ve seen though, is that many patients have a fairly low score overall on the TSK, particularly characterised by a low score on the ‘harm’ scale.  At the same time, these patients have been among the most fearful of the patients I see of experiencing pain and most avoidant of specific movements.  Something is missing here.  I should add that the TSK is not administered alone, it’s included in a battery of questionnaires, and that along with the questionnaire responses, interview, observation and functional assessments are also carried out.

What I seem to see is that this group of people don’t *think* they’re fearful of harm – in fact, they almost all say they’ve been told, and accept that they’re not doing any damage to their body, but at the same time they’re strongly avoidant of movements that provoke their pain.  When I ask them what might happen if they do the movement they’re avoiding, often they’ll say something like ‘I don’t want to increase my pain, it hurts too much, and I’ll never sleep’.  Yeah, catastrophising.

Some of the other measures do correlate with their avoidance – disability measures, of course; low mood quite often; low pain self efficacy; and very often high catastrophising on a couple of the other measures we use.

What I think I’m seeing is that in a group of patients who often have had prior pain management input, there is a ‘head knowledge’ (ie they’ve had ‘information’ or ‘education’ about hurt vs harm), but they haven’t developed at least two things:

And importantly, their underlying level of catastrophising doesn’t seem to have been addressed.  Or at least that’s one hypothesis.

A measure I used to use a lot, but seems to have fallen out of favour is the Pain Anxiety Symptoms Scale (especially with ACC in New Zealand publishing a ‘Compendium of Pain Measures’ that seems to have ranked questionnaires on somewhat arbitrary factors).  The PASS is a scale originally developed by McCracken and colleagues, and has four factors: cognitive anxiety, fearful appraisal, activity avoidance and physiological arousal.  There is a shorter version recently used by Carleton & Asmundson (2009).

This was a useful measure to me because it helped to identify the way in which anxiety about experiencing pain might be affecting the individual, and suggested some ways to address this.  For example, if the person scored very high on cognitive anxiety, it might be difficult for them to think of coping strategies during pain flare-ups.  If the person indicated high physiological arousal, helping them develop effective relaxation strategies often gave them tools to manage the situation with feeling ill.

It might be helpful to use the PASS with these patients who don’t believe they’re fearful of pain, but do avoid.  But I’m still not sure that this taps into exactly what underlies the avoidance behaviour.

Why am I worried about this? Well, if I’m trying to identify who to select for specific exposure therapy, the TSK has been suggested as a useful screening tool – and one that can demonstrate change over time.  But if the person doesn’t reach a certain ‘cut-off’ point, this approach might be overlooked.  If I use the PASS, I might identify the ‘what happens’ aspect, but I might not identify the avoidance component.  If I only look at catastrophising, I might reduce catastrophising, but fail to help the patient successfully engage in *real* activity despite pain.

I’ve pondered whether there is another way of approaching the assessment of fear and avoidance of pain – some combination of the activity avoidance subscale of the TSK or the PASS, with a measure of fear of pain.  Maybe something like Fear of Pain Questionnaire (Short Form), but I’m not sure.

In terms of what to do for treatment: I wonder whether the increasing emphasis on cognitive strategies, or ‘education’ about chronic pain has reduced the opportunity for behavioural approaches to be included in pain management.  For some psychologists, behavioural approaches like reducing pain behaviour and exposure therapy appear to have become a little passe.  This can leave physiotherapists and occupational therapists (who may not always have had the background knowledge about how to conduct exposure therapy) in the position of trying to help a rather reluctant patient start to do the very things they’ve been avoiding.  And while ‘just doing it’ is a behavioural strategy, good knowledge and skills about the cognitions the patient has and how to work with them is vital, or the response may be to reinforce the patient’s beliefs that they were indeed right to avoid those activities!

Exposure therapy is not the same as ‘graduated reactivation’. It’s also not the same as the approach used to reduce sensitivity in a CRPS limb – which should probably more appropriately be called ‘graded desensitisation’.

Anyway, back to my musings: my concern is that ACC in New Zealand is starting to specify the questionnaires that ’should’ or ‘must’ be used in treatments.  And the risk is that on the basis of cut-off scores for the TSK, these highly disabled patients might not receive the sort of cognitive and behavioural input they need.  As well, there are few ways to measure progress over time, apart from the level of engagement in tasks.

As we all know well, there are many different reasons for people to fail to reduce their disability despite having had effective pain management – but for an eager case manager (and some ill-informed clinicians), failure to reduce disability can be attributed to ‘lack of motivation’, or ‘failure to comply with treatment’, or something equally unhelpful.  Without a good clinical model, effective measurement instrument, well-conducted treatment and adequate support, I worry that we risk focusing too much on the measurement properties of the TSK in our clinical practice, and that the pain-related anxiety and avoidance (Fear-avoidance) model doesn’t always explain the situation for our patients.

As usual, more research required – someone’s PhD I hope! In the meantime, I’m hoping to carry on pondering, and wandering through the research papers to find out if anyone else has come up with a model and/or measurement tool that might be useful.  If you’ve got one – drop me a line, I’d love to know!

McCracken LM, Zayfert C, Gross RT: The Pain Anxiety
Symptoms Scale: Development and validation of a scale to
measure fear of pain. Pain 50:67-73, 1992

CARLETON, R., & ASMUNDSON, G. (2009). The Multidimensionality of Fear of Pain: Construct Independence for the Fear of Pain Questionnaire-Short Form and the Pain Anxiety Symptoms Scale-20 The Journal of Pain, 10 (1), 29-37 DOI: 10.1016/j.jpain.2008.06.007

Ostelo RW, Swinkels-Meewisse IJ, Knol DL, Vlaeyen JW, & de Vet HC (2007). Assessing pain and pain-related fear in acute low back pain: what is the smallest detectable change? International journal of behavioral medicine, 14 (4), 242-8 PMID: 18001240

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