pain assessment

An introduction to case formulation


ResearchBlogging.org

One definition of case formulation is ‘Case formulation aims to describe a person’s presenting problems and use theory to make explanatory inferences about causes and maintaining factors that can inform interventions’. What this means is that it is essentially a story not just to describe, but explain, how a person’s problem has developed, and how it is maintained so that treatments can be based on influencing those factors.

There are many different frameworks for case formulation, but several key elements are usually present:

  1. a description of the presenting issues;
  2. the factors that act to create vulnerability or precipitate the problems developing;
  3. factors that may not have been involved in the initial problem developing, but are helping to maintain the problems; and finally,
  4. factors that can help the person cope or act as resources.

To move beyond just describing these factors, a case formulation should describe the relationships between these various factors and the problems that are present – and should reflect not just the visible features of the problem (ie what we can see, or what the person reports that are unique to his or her situation), but also the underlying phenomena or stable, recognisable features that are present. (more…)

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‘its taken over my life’…


Each time I spend listening to someone who is really finding it hard to cope with his or her pain, I hear the unspoken cry that pain has taken over everything. It can be heartbreaking to hear someone talk about their troubled sleep, poor concentration, difficult relationships, losing their job and ending up feeling out of control and at the mercy of the grim slave-driver we call chronic pain. The impact of pain can be all-pervasive, and it can be hard to work out what the key problems are.

To help break the areas down a little, I’ve been quite arbitrary really. I’m going to explore functional limitations in terms of the following:
1. Movement changes such as mobility (walking), manual handling, personal activities of daily living
2. Disability – participation in usual activities and roles such as grocery shopping, household management, parenting, relationships/intimacy/communication
3. Sleep – because it is such a common problem in pain
4. Work disability – mainly because this is such a complex area
5. Quality of life measures

The two following areas are ones I’ll discuss in a day or so – they’re associated with disability because they mediate the pain experience and disability…as I mentioned yesterday, they’re the ‘suffering’ component of the Loeser ‘rings’ model.
6. Affective impact – things like anxiety, fear, mood, anger that are influenced by thoughts and beliefs about pain and directly influence behaviour
7. Beliefs and attitudes– these mediate behaviour often through mood, but can directly influence behaviour also (especially treatment seeking)

There are so many other areas that could be included as well, but these are some that I think are important.
Before I discuss specific instruments, I want to spend yet more time looking at who and how – and the factors that may influence the usefulness of any assessment measure.

Who should assess these areas? Well, it’s not perhaps who ‘should’ but how can these areas be assessed in a clinical setting.

Most clinicians working in pain management (doctors, psychologists, occupational therapists, physiotherapists, nurses, social workers – have I missed anyone?) will want to know about these areas of disability but will interpret findings in slightly different ways, and perhaps assess by focusing on different aspects of these areas.

As I pointed out yesterday, there are many confounding factors when we start to look at pain assessment, and these need to be borne in mind throughout the assessment process.

How can the functional impact of pain be assessed?

  • Self report, eg interview, questionnaires – and the limitations of these approaches are reliability, validity threats as well as ‘motivation’ or expectancies
  • Observation, either in a ‘natural’ setting such as home or work, or a clinical setting
  • Functional testing, again either in a ‘natural’ setting such as home or work, or a clinical setting – and functional testing can include naturalistic procedures such as the AMPS assessment, formal and structured testing such as the 6 minute walk test, the sock test, or even certain functional capacity tests; or it may be clinical testing such as manual muscle testing or range of movement, or even Waddell’s signs

All self report measures, whether they’re verbal questions, interview or pen and paper measures are subject to the problem that they are simply the individual’s own perception of the degree of interference they attribute to pain. The accuracy of this perception can be called into question especially if the person hasn’t carried out a particular activity recently, but in the end, it is the person’s perception of their abilities.

All measures need to be evaluated in terms of their reliability and validity – how much can we depend on this measure to (1) assess current status (2) contribute to a useful diagnosis (or formulation) (3) provide a basis for treatment decisions (4) evaluate or measure function over time (Dworkin & Sherman, 2001).

Reliability refers to how consistently a measure performs over time, person, clinician.

Validity refers to how well a test actually measures what it says its measuring.  The best way to determine validity is if there is a ‘gold standard’ against which the test can be compared – of course in pain and functional performance, this is not easy, because there is no gold standard!  The closest we can come to is a comparison between, for example, a self report in a clinic on a pen and paper test compared with a naturalistic observation in a person’s home or workplace – when they’re not being observed.

Probably one of the best chapters discussing these aspects of pain assessment is Chapter 32, written by Dworkin & Sherman chapter in the 2nd Edition of the Handbook of Pain Assessment 2001 (DC Turk & R Melzack, Eds), The Guilford Press.

Importantly for clinicians working in New Zealand, or outside of North America and the UK, the reference group against which the client’s performance is being compared, needs to be somewhat similar to the population the client comes from.  Unfortunately, there are very few assessment instruments that have normative data derived from a New Zealand or Australasian population – and we simply don’t know whether the people seeking treatment in New Zealand are the same on many dimensions as those in North America.

I’m also interested in how well any instruments, whether pen and paper, observation or performance-based assessment translate into the everyday context of the person.  This is a critical aspect of pain assessment validity that hasn’t really been examined well.  For example, the predictive validity (which is what I’m talking about) of functional capacity tests such as Isernhagen, Blankenship or other systems have never been satisfactorily established, despite the extensive reliance on these tests by insurers.

Observation is almost always included in disability assessment. The main problems with observation are:
– there are relatively few formal observation assessments available for routine clinical use
– they do take time to carry out
– maintaining inter-rater reliability over time can be difficult (while people may initially maintain a high level of integrity with the original assessment process, it’s common to ‘drift’ over time, and ‘recalibration’ is rarely carried out)

While it’s tempting to think that observation, and even functional testing, is more ‘objective’ than self report, it’s also important to consider that these are tests of what a person will do rather than what a person can do (performance rather than capacity). As a result, these tests can’t be considered infallible or completely reliable indicators of actual performance in another setting or over a different time period.

Influences on observation or performance-based assessments include:
– the person’s beliefs about the purpose of the test
– the person’s beliefs about his or her pain (for example, the meaning of it such as hurt = harm, and whether they believe they can cope with fluctuations of intensity)
– the time of day, previous activities
– past experience of the testing process

And of course, all the usual validity and reliability issues.
More on this tomorrow, in the meantime you really can’t go far past the 2nd Edition of the Handbook of Pain Assessment 2001 (DC Turk & R Melzack, Eds), The Guilford Press.

Here’s a review of the book when the 2nd Edition was published. And it’s still relevant.

The two faces of pain assessment


This week’s focus is on assessing or evaluating or getting to understand the experience of pain.  There are many reasons to assess someone’s pain, from trying to diagnose the kind of pain they have to attempting to see if someone is ‘real’ or not!  And shades in between.  I’m going to focus on ‘genuine’ reasons to understand someone’s pain experience rather than policing whether the person is a good actor or not, because as I’ve said before, I don’t think very often about people ‘faking’, and because I think it might be more helpful to try to see the world from the person’s eyes first.

So, given that pain is a multidimensional experience, why do I say there are two faces to pain assessment? Well the two I’m thinking of are:
(1) the experience of pain itself – location, quality, intensity etc, along with the beliefs and risk factors that influence the ‘suffering’ component of the ‘onion ring’ model described by Loeser and others.
(2) the impact of pain on function – disability, sleep loss, effect on relationships, work and so on.

I’m going to leave the first aspect for a while, and spend some time looking at the impact of pain on the individual and his/her family/community, but before I do I want to consider some basic concepts relevant to pain assessment that are essential before even beginning to think about the ‘how’ of assessment!

Firstly, all pain assessment is subjective. What that means is that as outside observers, we cannot determine whether the person is actually experiencing what they say (or indicate) they are experiencing. We can’t reliably establish whether someone is or is not carrying out activities to their full capacity. We can’t accurately determine whether a certain number of pain behaviours is the ‘correct’ amount of behaviour for the amount of nociception present.

Secondly, all behaviour is subject to the effects of learning and reinforcement that are well-established in the psychological literature (and in any two-year-old child wanting sweets!). As a result, it’s difficult to tell whether someone is behaving in a certain way because of years of learning within their family context, or whether it’s more immediate social environment demand characteristics that are influencing how the person is performing. We would all probably do more for someone that was holding a gun to our heads than for someone who looked bored (and we knew the results were going to determine whether we got some money!).

Thirdly, what we will or won’t do is also influenced by what we think we can or can’t do – and what we anticipate may happen afterwards, or what we experienced last time we attempted. A recent study of functional capacity evaluations found that even for people without chronic pain, a majority of participants experienced elevated pain the day after completing an FCE, so my guess is that some people who have chronic pain and who have completed a previous FCE may modify their performance at the next one. Our beliefs, attitudes, predictions, memories and so on determine what we are prepared to do in any context. When we look at the impact of pain on function, we need to remember this and take these factors into account.

The final area to consider today is the effect of context on performance. In many ways this is a summary of the three previous areas I’ve mentioned, but bear with me as I explain.
Many people with chronic pain report that they can carry out an activity in one setting, once, but when asked to carry it out repeatedly, and in a work setting, for example, they struggle. In the context of the real world, with all the social cues, cognitive load and need to persist and maintain activity over time, performance becomes variable. This doesn’t just happen for people with persistent pain mind you – let’s think of those Olympic athletes who may have performed well ‘at home’, but in the context of The Olympic Games in China in Front of All Those People – performance may well be very different.

I’ve only mentioned a few of the confounding factors that influence how pain may impact on a person’s daily activity in life and roles. I haven’t even started to use references – but you can bet if you come back this week, there will be more!