pain intensity

Why reducing pain intensity doesn’t always mean a better outcome


There have recently been some studies published on meta-analyses of “pain education”. I’ve made my stance clear on what I think of “pain education” particularly as a stand-alone intervention here and here and why I think we need to look beyond pain intensity reduction as The Outcome of Choice. In this brief post I want to look at some of the variables that influence both pain behaviour and pain intensity.

We all know that pain is subjective: this means it can’t be directly shared with anyone, and no-one is able to determine just how sore any other person is (that includes people who believe they can spot faking or malingering. Stop it! You can’t, not for pain). What this also means, though, is that for us as clinicians to understand what it is like for another person to be experiencing pain, we must infer on the basis of what they do (ie behaviours).

Mostly with adults, we infer the severity of pain on the basis of the dreaded visual analogue scale or the numeric rating scale – “what is your pain on a 0 – 10 scale where 0 = no pain at all and 10 = most extreme pain you can imagine.” In people who either don’t speak our language, or who can’t respond with words, we rely on inferences drawn from their “body language” or nonverbal behaviour.

Many pain behaviours begin as useful evolutionary responses to threat: physiological arousal, reflex withdrawal, verbal groans and gasps. These serve to help us withdraw from the stimulus, help us escape the threat (or freeze or fight it), and signals that we need help (and avoid this threat) because we’re social animals. At the same time, behaviours are subject to behavioural reinforcement as well as cognitive biases, memories and so on. An example: If someone goes to the Emergency Department and reports their pain is 3/10, they’re unlikely to receive heavy-duty analgesia. You can bet that if they attend ED on another occasion, they’ll remember this and report their pain to be a little higher. Now often this isn’t a conscious decision, it’s something we learn over time and throughout our lives, so we may be oblivious to how we alter our verbal and nonverbal behaviour as a response to events in the environment and our own interpretations of what’s going on.

Pain is also rarely a static, consistent experience. Pain typically varies over the course of time. It can be episodic and pulsing and rhythmic, or it may come in waves, it might fluctuate unpredictably: in part this variability is a product of the stimulus, but also physiological processes such as habituation, attentional demands can mean we’re more or less “tuned in” to being aware of pain, and our emotional state is also part of the picture.

Finally (or not, depending on my whim!), our response to pain depends on our interpretation of its meaning and significance. When we’re tired and feeling down, and the pain seems mysterious and very threatening because we have things to do and no-one can tell us what the diagnosis is we’re more likely to increase our awareness and our behaviour associated with that experience. Maybe we’ll report it as 9/10 because it seems to intrude on life, the universe and our very existence as we know it. Maybe we’ll be really afraid and don’t think we can cope with it even though we usually do, so we’ll report it as 12/10. Maybe we’re not experiencing pain right now but we think that if we do something wrong we’ll get the pain back (think of angina here), so we just don’t do things “in case”. And maybe we’ve been told not to do things because it might be harmful, so we don’t do those things, our pain is around its usual level but we feel constrained and report it as 7/10 because we’re fed up with it all.

We know that part of the challenge of pain is that it’s incompletely understood (I use the word “it” as a placeholder for the rather more wordy “our experience of pain”). We do have pretty good means of reducing pain, but the problem is that these leave us incapable of doing very much because the most effective approach is simply to lose consciousness. But life doesn’t permit us to do that for long without adverse consequences! And for many people, even the best analgesia is only likely to reduce pain by about 30%, if at all.

When someone has learned to reinterpret their pain as not terribly threatening, still annoying and frustrating and demoralising, but not indicating that the body/self is about to come to serious harm, it’s possible to look well but feel awful inside. In other words, the pain intensity and quality doesn’t change an awful lot, but because it’s no longer associated with existential threat to self, it’s possible to put on makeup, groom well, interact happily, and look “normal”. How do I know this? Well – that’s what I do every day.

So using pain intensity as a guide to how well a person has recovered or adjusted to their pain is not an especially reliable guide as to how much pain is bothering them. The relationship between pain intensity and what we can and cannot do is uncertain and complex. And behaviour change is not easy. Doing things differently involves a whole cascade of changes that need to be implemented, not the least of which is learning how to regulate physiological arousal, reconceptualising the pain experience as something that can be lived with, redirecting attention towards things that matter to us, developing motor control and strength when this has changed – but possibly the most complex and ignored involves responding to, or altering our response to other people’s behaviours.

This means navigating other’s expectations from us (some people are afraid that when a person begins doing things again they’re going to make their pain worse and fail, others are expecting return to “normal” without factoring in that pain IS a significant challenge to deal with), and their behavioural responses to what we do. Many of the people I work with who live with pain talk about losing friendships, not being able to keep up with others, being misunderstood, being ignored or punished with angry reactions because they’re not the same person they were before their encounter with weird prolonged pain. And these are only the responses at an individual and small group level! What about the perverse disincentives to return to usual activities, like losing compensation prematurely, or having to return to a job that is not the job you left and you feel unprepared for or overskilled and unappreciated? Legislation that is written for “normal” recovery from illness or injury but doesn’t include persistent pain. Processes that mean you have to prove disability repeatedly just to retain access to services or income.

So, even if clinicians find that their treatment reduces pain, it may not lead to the outcomes clinicians want to see: a happy, active and engaged person. Sometimes it can lead to ongoing life restrictions (think angina again). Sometimes it can lead to erratic activity patterns. Sometimes those other factors influence how the person goes about life and not in a good way.

Echoing something written repeatedly over the decades in pain research literature, I want to quote from Ballantyne and Sullivan (2015). This article challenges clinicians to rethink pain reduction as the primary outcome measure for persistent pain in the face of increasing opioid use (now reducing but often without subtlety or support) because of the very issues I’ve outlined above. They state the following:

Suffering may be related as much to the meaning of pain as to its intensity. Persistent helplessness and hopelessness may be the root causes of suffering for patients with chronic pain yet be reflected in a report of high pain intensity.

And conclude their article with this:

When pain is chronic, its intensity isn’t a simple measure of something that can be easily fixed. Multiple measures of the complex causes and consequences of pain are needed to elucidate a person’s pain and inform multimodal treatment. But no quantitative summary of these measures will adequately capture the burden or the meaning of chronic pain for a particular patient. For this purpose, nothing is more revealing or therapeutic than a conversation between a patient and a clinician, which allows the patient to be heard and the clinician to appreciate the patient’s experiences and offer empathy, encouragement, mentorship, and hope.

Emphasis is entirely mine. And heartfelt.

Ballantyne, J. C., & Sullivan, M. D. (2015). Intensity of chronic pain—the wrong metric? New England Journal of Medicine, 373(22), 2098-2099.

Numbers on a scale: How bad did you say your pain was?


ResearchBlogging.org
Have you ever been asked to give your pain rating on a scale of 0 – 10 (where 0 = no pain at all and 10 = most extreme pain you can imagine)? Have you ever tried to work out whether today’s pain is worse than yesterdays? What does a pain rating tell us?

I’ve struggled to work out how “bad” my pain is many times, is it the pain intensity that makes it troublesome? Or, in the case of a migraine, is it the quality of the pain that makes it bad (or the nausea?). Health professionals often ask people to summarise their pain experience into a form that (hopefully) we can all understand – but just what does a pain that’s around 4/10 on a VAS actually mean?

Why do we use rating scales?

We know that pain is subjective, just like taste and colour. While we might be able to agree that both of us are tasting something we call “banana”, we don’t know whether the banana taste I experience is the same as the banana taste you experience. We can see that both of us are eating the same fruit, but we don’t know how our body/brain processes that experience. Instead we assume, or infer, that we’re experiencing it in a similar way because of the similarities in context.

With pain, the situation is even more complex: we can’t determine whether the pain I feel is similar to the pain another person feels, and we don’t even have the benefit of similar “tissue damage” in the case of a migraine headache.

So, we have to infer something about the experience through some sort of common mechanism. Mostly that’s language. We hope that someone can understand that a higher number means greater pain. We hope the person can recognise what “no pain” feels like and where it might be represented on a scale. We ask the person to remember their current pain intensity, translate it into a number that in turn represents to us some kind of common understanding of what pain given that number might feel like.

Of course, there are problems with numbers on a scale. For a child who doesn’t understand the association between numbers on a scale and intensity, we use the “Faces” scale. For a person with cognitive problems (brain injury, stroke, dementia), we observe their behaviour (and hope we can translate well enough). For a person who doesn’t speak the same language as us, we might try a sliding scale with green at the bottom and red at the top, to represent increasing intensity – appealing, perhaps, to a common understanding that green = OK and red = not OK.

Worse than the difficulty translating from experience to a number is the common misunderstanding that pain severity alone represents the “what it is like” to experience pain. We know personally that it doesn’t – after all, who has had a toothache that represents “Oh no, I need a root canal and that’s going to cost a bomb!”, or “Ouch! That lemon juice in the paper cut on my finger is really annoying”, or “I feel so sick, this migraine is horrible”.

Hopefully most health professionals are taught that to use just one measure of pain is not enough. It’s important to also include other aspects of pain such as quality, how it affects function (interference), how confident we are to deal with life despite the pain (self efficacy).

So we use rating scales as a shorthand way to get to understand a tiny bit of what it is like to have pain. But the Visual Analogue Scale (VAS) is used many times to estimate whether “this person’s pain is so bad they need medication”, or “this person’s pain means we can’t expect her to help move herself from the ambulance trolley to the wheelchair”. The VAS can be used in many ways it shouldn’t be.

Studying the relationship between VAS pain intensity and disability (SF36)

The study by Boonstra, Schiphorst Preuper, Balk & Stewart (in press) aimed to identify cut-off points on the VAS to establish “mild”, “moderate” and “severe” using three different statistical approaches.  They measured pain using a Verbal Rating Scale (mild, moderate and severe), the VAS, and used several scales from the SF36 (a measure of general health quality) to establish interference from pain.

What they found was that while “mild” pain was fairly equally determined (less than or equal to 3.5), and correlated with both severity and function, when it came to “moderate” and “severe” pain, there was far less agreement. In fact, this group found that individuals could verbally rate their pain as “moderate” but at the same time report severe levels of interference. This means verbal descriptors under-represent the impact of pain on performance.

They also found that the cut-off point between “mild” and “moderate” pain in terms of interference with activity ranged between 2.5 – 4.5, and for moderate to severe pain between 4.5 – 7.4.  The associations between pain intensity and disability or interference were low to moderate and as a result these authors argue that it is “questionable” to translate VAS scores into verbal descriptors, because the different instruments measure different things.

What does this tell us?

It should be easy by now to tell that although we use numbers as a shorthand for “how bad is your pain?” in reality, they don’t directly translate the “what it is like” to have pain. Neither does the VAS correlate well with measures of disability or interference from pain. While people with mild pain might be also experiencing only a little disability, when the numbers go up the relationship between intensity and function disappear.

I think we might be trying to quantify an experience as a quick way to make clinical decisions. Really, when we ask “how bad is your pain”, depending on the context, we may be asking “do you need pain relief?”, “do you need help to move?”, “did my treatment help?” or any myriad other questions. The trouble is in research, we can’t do statistics nearly as easily on a “yes” or “really bad” or “it didn’t change much” answer. But how many of us work routinely in research settings?

I wonder whether it’s worth asking ourselves: do I need to ask for a pain rating, or should I ask a more useful question? And take the time to listen to the answer.

 

Anne M. Boonstra, Henrica R. Schiphorst Preuper, Gerlof A. Balk, & Roy E.Stewart (2014). Cut-off points for mild, moderate and severe pain on the VAS for pain for patients with chronic musculoskeletal pain Pain DOI: http://dx..org/10.1016/j.pain.2014.09.014

Distress and wellbeing – two sides of the same coin?


ResearchBlogging.org

Predictors of psychological distress and well-being in women with chronic musculoskeletal pain: Two sides of the same coin?
Alexa Hubera, Anna Lisa Sumana, Giovanni Biasib, Giancarlo Carlia

This is an interesting article on the concepts of wellbeing and distress. Distress is often considered a key element in whether someone has ‘good quality of life’ (see my post from a day or so ago), but in this article, the relationship between psychological distress and well-being was explored, and the predictors of both in patients with chronic nonmalignant pain are identified.

Why would we be bothered about distress and how is it measured? Distress is not a particularly well-defined concept, but is often referred to in the same breath as ‘eustress’ and ‘distress’ (see this entry in Wikipedia for an exploration of several theories relevant to stress and coping). If its used in this way, it often refers to suffering (which is about negative judgements of a situation or event), and is distinct from depression. Using Loeser’s onion rings model of pain, it’s the emotional judgement of pain that negatively impact on the individual.

In this article, however, the authors refer to two traditions and the impact these traditions have on our ideas about wellbeing. To quote ‘[the] hedonic approach focuses on happiness, while the eudaimonic approach defines well-being in terms of the degree to which a person is fully functioning, which may or may not be accompanied by feeling good.’
This reminds me of the traditional WHO definition of health – which is not simply the absence of disease!

One of the reasons I was drawn to this study was the statement by the authors that ‘To date, few studies on well-being in patients suffering from chronic pain have been published’. (Of course I’d argue that experiencing chronic pain may be mandatory, but ‘suffering’ is optional!) This is precisely the point I’ve been trying to make for some time in that most of our knowledge about people experiencing chronic pain is drawn from people who are seeking treatment. People who live well despite having chronic pain are not studied often and hence we know relatively little about them.

So, getting down to the nuts and bolts of this study: 69 women recruited from a University Hospital Rheumatology centre. The majority of them met criteria for fibromyalgia, while the remainder had widespread pain, and many of them also experienced other conditions associated with central sensitisation syndrome (e.g. psoriasis, irritable bowel syndrome, headache, fatigue).
They all completed a raft of measures, but the ones I want to focus on are those assessing distress:
The Symptom Check List-90 (SCL-90) measures psychiatric symptoms and psychological distress and has been used often in this type of research.
The State–Trait Anxiety Inventory Form Y (STAI-Y) consists of two scales measuring state (STAT-Y1) and trait anxiety (STAT-Y2), respectively. It’s been used in many studies of anxiety in different patient and community groups.


The Multidimensional Affect and Pain Survey (MAPS)was used to measure pain-related emotional suffering and well-being. It consists of 101 descriptors within 30 clusters, grouped into three scales.
1.
The Somatosensory Pain scale measures somatosensory pain sensations, and its results weren’t considered in this study.
2.
The Emotional Pain scale (EP) measures pain-related emotional suffering within eight areas: Physical Illness, Depressed Mood, Self-Blame, Anger, Anxiety, Fear, Apathy, and Fatigue.
3.
The Well-Being scale (WB) measures aspects of wellbeing in five clusters. The first two clusters—Mentally Engaged (e.g.,“interested”) and Physically Active (e.g., “vigorous”)— measure healthy activities and follow the eudaimonic tradition (which defines well-being in terms of functioning, not happiness).
The third and fourth clusters—Affiliative Feelings (e.g.,“sympathetic”) and Positive Affect (e.g., “happy”)—measure happy thoughts and really within the hedonic tradition. The fifth cluster, Treatable Illness, measures to what extent the patient believes that his/her illness is “curable” or “manageable” and represents a separate dimension of well-being.

(Just a comment – I’m not sure of the relationship between this measure and measures of acceptance such as those being studied by McCracken and others).
The other variables included in this study were ‘general epidemiological–anamnestic questionnaire, six measures of physical symptoms (tender point count, pain area, pain intensity, fatigue, stiffness, and physical disability).

Now for some statistics – not particularly challenging ones, so don’t panic!
Pearson correlation coefficients were used to assess the relationships between measures of well-being and psychological distress, applying Bonferroni adjusted α levels.

These showed only three physical symptoms—pain intensity (VAS), number of positive tender points, and physical disability (FIQ)— showed meaningful correlations with psychological distress and/or well-being.

A hierarchical multiple regression analysis was carried out to separately predict each of the six measures of well-being (WB-4 and each of the five WB clusters) and three measures of psychological distress (MAPS EP, STAI-Y2, and SCL-90 GSI).  ‘Predictors were entered in the following order in five steps: (a) age; (b) pain duration (i.e., time passed since the onset of pain symptoms); (c) pain intensity; (d) number of positive tender points; and (e) physical disability.‘ Just so you know, several of these were mathematically transformed to make the stats assumptions work (which may affect the rigour of the results), but at least they told you about it!

Ok, results.
Well, almost half the participants reached the cut-off score for trait anxiety, and many of them also reached the score for high distress.  They sound fairly like the people that get referred to Burwood Pain Management Centre.

In terms of psychological distress, higher age and more physical disability emerged as the two most important predictors of psychological distress, each making unique contributions.

‘Both Pearson correlations (and multiple regression demonstrated that wellbeing (as measured by WB-4) was significantly predicted from low physical disability alone, and was independent of age, pain duration, pain intensity, and tender point count.’

What does this actually mean?
The results really show that the relationship between psychological distress and pain-related symptoms, may be mediated by the patient’s limitations in the capacity to perform daily household chores (ie disability).

We know that disability is influenced by a whole range of factors including the responses of significant others – and the cognitive interpretation of the meaning of those limitations, such as the disparity between what the person believes is expected of them as compared with what they believe they are capable of.  It’s not simply about pain intensity.

Wellbeing, on the other hand, decreased with higher disability but, in contrast to psychological distress, was independent of age, pain intensity, and tender point count.

Now the finding that well-being was independent of pain intensity is an important result of this study.

Yesterday I quoted from Katz where it was assumed that if pain intensity alone was reduced, ‘quality of life’ would improve. I wouldn’t want to equate ‘quality of life’ with ‘wellbeing’ – but the dimensions are similar, and suggest that it’s simply not enough to reduce pain without simultaneously addressing other issues that are important to the individual.

As the authors state ‘Our findings suggest that, in patients with chronic musculoskeletal pain, well-being is related to aspects of physical disability that are not directly linked with pain. The results are in line with the literature demonstrating that the negative impact of chronic pain on physical functioning and work status is moderated by cognitive and psychosocial factors, such as pain catastrophizing and pain-related fear of movement.’

They add ‘Results are consistent with the view that pain behavior, rather than pain per se, should be the target of treatment’. Not news to many of us, but perhaps to those clinicians with a somewhat simplistic (or perhaps simply a biomedical) viewpoint, it may be surprising.

I’m also keen to support their contention that psychological wellbeing should be measured as an outcome quite distinct from a reduction in psychological distress. It’s a new concept for health care – to think that along with ways to reduce distress, clinicians could also consider ways to enhance wellbeing – and that this can occur in the absence of a focus on pain reduction.

It makes me think that the emerging field of positive psychology is something that pain management clinicians could well start to view more seriously. My post from the other day on counting blessings comes to mind. And for those of us working in the field for the long term – it might make our work just a little lighter and more fun!

HUBER, A., SUMAN, A., BIASI, G., CARLI, G. (2008). Predictors of psychological distress and well-being in women with chronic musculoskeletal pain: Two sides of the same coin?. Journal of Psychosomatic Research, 64(2), 169-175. DOI: 10.1016/j.jpsychores.2007.09.005

Why can he go surfing but can’t do the vacuuming?


ResearchBlogging.org

Social contract theory is a theory drawn from evolutionary psychology – a ‘cheater detection’ system if you like. Following on from yesterdays post about detecting faking in pain, this study examines the judgements observers (in this case, friends and relatives of people with pain) in a study where four vignettes were presented. Each vignette varied in terms of four cues: the person continuing or stopping liked tasks, continuing or stopping disliked tasks, the availability of medical evidence, and the pain intensity as rated by the person.

Many variables have been studied with respect to how accurately observers judge another person’s pain – attractiveness, gender, ethnicity, social class, as well as the context (return to work or post-surgical), and the characteristics of the observer (parent, caregiver, spouse, clinician).

Results from past studies have included: unattractive patients were judged to suffer from more pain than physically attractive patients (Hadjistavropoulos et al.1990, 1996, 2000). Generally, higher reported pain intensity appeared to invite higher estimated pain intensity. When comparing sufferers’ self-reports and observers’ estimates, however, low reported pain intensities were overestimated and high reported pain intensities were underestimated (Chibnall and Tait 1995; Chibnall et al. 1997; Krokosky and Reardon 1989; Tait and Chibnall 1997; Zalon 1993).

For health professionals, some studies found no associations (Dudley and Holm 1984; Everett et al. 1994; Hamers et al. 1997; Oberst 1978; van der Does 1989), others found that less experienced observers gave higher pain estimates than did more experienced observers (Mason 1981; Perry and Heidrich 1982; Lenburg et al. 1970).

In terms of contextual cues, the absence of medical evidence to support the person’s report of pain has been associated with lower estimates of pain.

Yesterday I briefly discussed the idea of malingering being the purposeful faking of health problems in order to gain financial benefit: in this study, the evolutionary value of the ‘social contract’ is used as the theoretical model for evaluating our sensitivity to these responses. Social contracting is a situation where the ‘‘individual is required to pay a cost, or meet a requirement, to an individual (or group) in order to be eligible to receive a benefit from that individual’’ (Cosmides 1989, p.197).

It makes sense that as humans we have some systems developed to determine whether we are being exploited and that the normal ‘contract’ between people is being disturbed. There is empirical support for humans being sensitive to cues for cheating from both human and animal studies (Cosmides 1989; Gigerenzer and Hug 1992;Wilkinson 1990) – but as we saw yesterday, we can be deceived reasonably readily, so it makes sense for us to be particularly sceptical about situations where we may be manipulated.

In a situation where one person is likely to receive benefits (caring or free food, for example) because of their reported pain, it makes sense for the observer to be more aware of cues suggesting that the individual receiving the ‘benefits’ is not actually in pain (Williams 2002). This has been studied before, and it has been found that suspicion of cheating or faking leads to conservatism and underestimation of pain. This can explain why such weight is given to medical evidence by health care professionals even when the relationship between ‘evidence’ from radiology and pain, for example, is fairly weak. This is especially true in cases where time off work, or other ‘special’ treatment is given as a result of confirmation of a ‘real’ problem.

The hypotheses in this paper were:
– the combination of two behaviours (continuing liked and
stopping disliked activities) would be judged as unfair
and lead to lower pain estimates, whatever the level of
pain,
– there would be no effect on pain estimates of the
presence or absence of medical evidence, and
– pain as reported by the patient would affect pain
estimates by relatives

Although the results were from a very small group of respondents in the end (only 23% of the initial group recruited actually responded with complete questionnaires), some interesting findings were obtained.
– people who stopped doing things they liked were interpreted as ‘having to stop’, and this was perceived as fair
– people who stopped things they didn’t like but continued with things they did like, were perceived as being unfair
– behaviour of characters reporting high pain was estimated to be fairer

The authors suggest that perhaps greater pain meant greater recognition of the cost in pain incurred by doing any tasks, or that more leeway was exercised in judgements of behaviour as fair or unfair.

– more pain was attributed to patients who stopped liked tasks
– highest pain levels were assigned to patients having stopped both liked and disliked activities
– lowest pain estimates were assigned to patients who had stopped disliked but continued liked chores, the combination which also received the lowest fairness ratings

The authors comment that these findings ‘support our hypothesis concerning lowering of pain estimates by individuals close to someone with persistent pain if they judge patients to be behaving ‘‘unfairly’’, that is, ‘‘accepting the benefits’’ of having pain—of being permitted not to do some tasks—‘‘while not meeting the requirement’’—of being unable to do other preferred activities.’

– participants’ estimates were not significantly affected by presence or absence of medical findings in this sample

– higher given pain intensities led to higher estimated pain intensities
– there were systematic discrepancies in estimates since low given pain intensities were estimated as higher and high given pain intensities as lower.

Some food for thought – this is a first cut study using social contract theory as a framework for determining a priori predictions as to which cues are salient, and in which direction. I look forward to finding out more on this – it may help us help our patients reflect on their behaviour, as well as the ways in which family members interpret and respond to patient’s behaviour.

There are some limitations to this study – in particular the small sample size, and the use of written vignettes rather than video-recorded scenarios. But for making us think? I think it’s great.

If you’ve enjoyed this post, there will be more tomorrow – and don’t forget you can use the RSS feed above to subscribe, or you can simply bookmark this page and come on back! I love comments and always respond, so don’t forget to let me know what you think of the topics I cover (***pssst! I don’t bite!***)

Kappesser, J., C. Williams, A.C. (2008). Pain judgements of patients’ relatives: examining the use of social contract theory as theoretical framework. Journal of Behavioral Medicine DOI: 10.1007/s10865-008-9157-4