The bigger picture: Pain and Cortical Change


Neuroplasticity has been defined as “the ability of the nervous system to respond to intrinsic and extrinsic stimuli by reorganising its structure, function and connections” (Cramer 2010)

A common example of neural adaptation that all can relate to is learning. Most I am sure have heard the term ‘practice makes perfect’ and some are aware of conditioning paradigms; remember being told the story of Pavlov and his experiment with dogs?

Central sensitisation is another example of adaptation. Allodynia and Hyperalgesia are known to be a symptom of central sensitisation and occur as a consequence of repeated activation of spinal nociceptors. Both symptoms can provide a biological advantage by increasing sensitivity to peripheral inputs. Increased sensitivity can potentially optimise the possibility of tissue healing and assist in preventing further injury. However ongoing sensitisation can pose a problem of its own when its benefit is lost such as in chronic pain.
It is well evidenced that among individuals with chronic pain the mere thought of a task can evoke pain and swelling. Equally, the observing a task  can elicit a painful response and the development of swelling though no action has taken place (Acerra and Mosely, 2005 and Mosely 2004).

Phantom limb pain and neuropathic pain following spinal cord injury were among the first pain states that identified a relation between pain and primary sensory cortex reorganisation. However, a wealth of evidence has since emerged that suggests a similar correlation exists  in patients with chronic musculoskeletal pain.

Mercier and Leonard, 2011 carried out a review that looked at the relation between pain and the motor cortex in patients with phantom limb pain and complex regional pain syndrome. Due to my musculoskeletal bias and purpose of this blog I shall  cover findings around complex regional pain syndrome.The review found that indeed there was evidence of change in motor cortex reorganisation in patients with complex regional pain syndrome.  The size of cortical representation of muscles on the affected side was found to be reduced in comparison to the unaffected side. Intra-cortical inhibition was found to be reduced in the motor cortex again in the unaffected side or bilaterally. Consistent with this reduced inhibition, an fMRI study showed that during a finger tapping exercise there was greater activation within the motor cortex and other areas when the exercise was performed by the affected hand compared to the unaffected. Such findings support that these alterations in motor function may be as a consequence of changes at cortical level and not just peripheral or spinal level.The review highlighted that several other factors may contribute to the reorganisation in the motor cortex other than pain alone as patients with chronic pain often have other sensorimotor defecits that could have an impact of motor-cortex excitability.  Motor  cortex  reorganisation was also thought to be dependent on the chronicity of the pain. The review hypothesised that cortical changes may also vary  dependent on the pain population. This hypothesis was based on studies that observed changes that occur at the level of somatosensory cortices. In patients with phantom limb pain and complex regional  pain the representation of the painful area decreased but increased in patients with low back pain and patients suffering from fibromyalgia. Thus suggesting cortical responses are specific to pathologies. The review posed the question: is it pain that drives plasticity within the motor cortex or, conversely does the motor cortex plasticity contribute to the development of chronic pain? Attempting to cover this may make me diverse somewhat and so I welcome ideas from the reader.

Camille et al, 2015 investigated whether there was a difference in motor cortical organisation among those with knee osteoarthritis (OA). The study  aimed to ascertain whether there was an association between cortical organisation and accuracy of a motor task.  11 participants who had moderate to severe OA and 7 asymptomatic individuals whom served as the control group were required to perform 3 visually guided, variable force, force matching motor tasks involving isolated muscle contractions of the knee (quadriceps), ankle (tibialis anterior), and hand (finger/thumb flexors). fMRI data was used to map the location of peak activation in the motor cortex during the three tasks. The results showed that there were differences in the organisation of the motor cortex during the performance of the knee and ankle motor tasks in those participants with knee OA. The differences in organisation was also related to the quality of performance of the knee motor task in this group too.

The differences in organisation presented as an anterior shift of the knee representation and a switching of the relative anterior-posterior arrangement of the knee and ankle representations in those with OA. The range of shift in the motor cortex representation was related to poorer performance and was specific to the knee. Organisation of the ankle and hand representations did not differ.
The greater the anterior location of the site of peak motor cortex activation during the knee tasks in those with OA in comparison to the site of those without OA signified substantial remodelling of that brain region.
The difference in location was measured and a similar range of remodelling of the motor cortex was also found in a study by Tsao et al, 2011 that looked at the representation of the longissimus erector spinal muscle in the back representation. Such changes in representation of muscles in the motor cortex was also linked with reduced coordination of trunk muscles. (Tsao et al 2008)
A systematic review by Henry et al, 2011 further supports the findings by Tsao et al, 2011 in the reorganisation of the motor cortex in chronic back pain. Schabrun et al, 2015 also confirmed that cortical reorganisation is accountable for clinical features of back pain. A general consensus among the literature is that  the amount of reorganisational change in chronic back pain increases with the chronicity of pain and not the intensity of the pain.

Lastly  a study by Ngomo et al, 2015 whom looked at whether rotator cuff tendinopathy lead to changes in central motor representation of a rotator cuff muscle. 39 participants with unilateral rotator cuff tendinopathy were recruited. The motor representation of infraspinatus was assessed bilaterally. Infraspinatus was chosen as according to Reddy et al, 2000 it is a rotator cuff muscle for which its movement pattern has been shown to be altered during arm elevation among those with rotator cuff tendinopathy. Also it is the only rotator cuff muscle that electromyographic activity can be directly recorded using surface electrodes.
In contrast to findings among other papers I’ve read the results of this study did not reveal any significant differences between the two hemispheres in cortical map location. However similar to other studies the study did show a higher motor threshold indicating a decrease in corticospinal excitability on the side of a rotator cuff tendinopathy. It too proposed that cortical changes is dependent on the duration of the pain. Most  studies that analyse cortical reorganisation  use functional MRI, this study used transcranial magnetic stimulation perhaps that may have implications on the findings.

So what’s next, what do these findings mean to us as clinicians and how does it alter our practice? Part 2 to come…

References

AcerraN, Mosely G. Dysynchiria: Watching the mirror image of the unaffected limb elicits pain in the affected side. Neurology. 2005;65:751-753

Cramer S. brain Repair after Stroke. New Engl J Med. 2010;362(19):1827-9

Flor H. The modification of corticol reorganisation and chronic pain by sensory feedback. Appl Psychophysiol Biofeedback. 2002; 27:215-227

Henry, D Chiodo A, Yang W. Central Nervous System Reorganizationn a variety of chronic pain States: A review. Phys Med Rehab. 2011;3:1116-1125

Mercier, C, Leonard G. Interactions between pain and the motor cortex: insights from research on phantom limb pain and complex regional pain syndrome. Physiother Can.2011;63(3);305-314

Moseley G and Flor H. Targeting cortical representation in the treatment of Chroninc Pain: A review. Neuro Rehab and Neural Repair. 2012;26(6)646-652

Moseley G. Imagined movements cause pain and swelling in a patient with complex regional pain syndrome. Neurology. 2004;(62):1644

Ngomo S, Mercier C, Bouyer L, Savoie A, Roy JS. Alterations in central motor representation increase over time in individuals with rotator cuff tendinopathy. Clinical Neurophysiology. 2015;126:365-371

Schabrun S, Elgueta-Cancino E, Hodges P. Smudging of the Motor Cortex in relation to the severity of low back pain. Spine.2015

Tsao H, Danneels LA, Hodges PW. Issls prize winner: smudging the motor brain in young adults with recurrent low back pain. Spine. 2011;36:1721-7.
Tsao H, Galae M, Hodges P. Reorganisation of the motor cortex in association with postural control deficits in recurrent low back pain. brain 2008;131(pt 8)2161-71

To approach with an approach or to approach our approach? Tackling the biopsychosocial presentation

So I recognise I have diverged somewhat from what I originally set out to explore. Initially, I set out to determine whether or not I managed patients who presented with biopsychosocial factors ‘correctly’. I wanted to explore what treatment approaches were most effective based on the current evidence.
After my most recent blog I begun to change my way of thinking. I thought it is all being well exploring what the most appropriate treatment approach is but if our views tend to be more biomedical orientated and as clinicians we do not recognise biopyschosocial factors well nor discuss and approach these factors with our patients then surely attempting to utilise a particular treatment approach may have little effect.
I then considered whether the beliefs and attitudes we take towards the biopyschosocial presentation of pain could have a detrimental effect on our patients, their clinical experience and consequently overall outcome.

A systematic review by Darlow et al (2012) set out to explore the association between healthcare professionals attitudes and beliefs and patient related factors in patients with low back pain. They hypothesised there would be an association between health care professionals attitudes and beliefs and patient attitudes and beliefs, patient clinical management and patient outcome.
The results showed a strong relationship between the attitudes and beliefs of patients with low back pain and the attitudes and beliefs of the health care professional that they were consulted by.
The review found the greater the perceived pathology and biomedical focus the more likely the recommendation not to work. This was found mostly among physiotherapists and general practitioners. Also, the higher the fear avoidance beliefs the more sick leave prescription and onward referral to specialist care there was.
Among general practitioners the higher the fear avoidance beliefs the less likely guidelines to physical and occupational therapy were followed.
Physiotherapists that held views that were more biomedically focused viewed activities as more harmful and advised patients to limit their activity. There was also an association between the education that was given to patients. Those with higher biomedical beliefs than those with a more biopsychosocial view gave less instruction and advice to patients. Sample sizes for these studies among practicing therapists in the musculoskeletal outpatient setting were small though.
Rheumatologists that tended to have high fear avoidance belief scores significantly increased the risk of patients also having a high score. Restrictive work and activity recommendations were also made more so by rheumatologists that held higher fear avoidance beliefs.

The study included studies of both qualitative and quantitive data. An extensive literature search was conducted of controlled trials. Studies were scrutinised, if deemed low quality based on if they fulfilled less than 50% of the criteria they were disregarded. The majority of the studies were cross sectional designs, two that were mostly relevant to physiotherapy were both semi structured interviews although the sample size and methodology was good the flexibility of the interview could flaw the results. The authors did consider the rigour of the studies that they identified, this increasing the reviews reliability. The authors used two reliable forms of assessing the strength of the evidence, the AHCPR and the GRADE rating. Attempts to reduce the sources of bias was made; a hypothesises was set from the start, two reviewers independently completed each stage of the review process and a range of reviewers collaborated from a number of institutions, countries, and backgrounds with different research interests and experience. The results of each of the studies were clearly displayed among the type of assessment methods. Assessment methods were in keeping with previous studies such as the Pain, Attitudes and Beliefs Scale (PABS).

The review highlights the negative effect that biomedical beliefs and attitudes that clinicians hold have on patient care. However, physiotherapists often recommend activity and exercise often justified by using a tissue based biomedical explanation. It appears the two schemas are still often seen as as being separate from each other. General Practitioners recognise the importance of psychological factors but seem to lack the time and training to incorporate it into practice. Thinking back to my second post where I looked at how the interpretation of pain can be shaped by a whole host of factors I touched on what influence the beliefs and attitudes that we have towards pain can have on the development of chronicity and disability and what effect how well our expectations of pain are managed can have on clinical outcome. As discussed in that post the literature suggests the better our expectations are managed the higher the likelihood of a better clinical outcome. Therefore it is not surprising that if expectations are poorly managed this can lead to pain catastrophising leading to poorer recovery and worse clinical outcome.

Looking at all of these points in this post, would it be fair to say that there is a likelihood of practitioners adding to the chronicity of pain in patients presenting with biopyschosocial factors.

Reference:

Darlow B, Fullen B, Dean S, Hurley D, Baxter G, Dowell A. (2011) The Assosciton between health care professional attitudes and beliefs and the attitudes and beliefs, clinical management, and outcomes of patients with low back pain: A systematic review. European Journal of Pain. 16 (2012) 3-17

Understanding the biopsychosocial orientation of pain and it’s incorporation into the clinical reasoning process.

Previously we explored what influence psychosocial factors can have on patients’ pain experience. Initially I believed it was all about how the patient presented, that influenced our clinical outcome, however I now aim to explore what influence clinicians’ beliefs on pain can have on their practice. But first what do clinicians believe pain is all about?

A systematic review by Parsons et al (2007) that explored the influence of patients’ and primary care practitioners’ beliefs and expectations on the process of care for chronic musculoskeletal pain found four common themes; Beliefs about pain, expectations of treatment, trust and patient education.
Within the review there seemed to be conflict in patients’ and general practitioners beliefs and causation of pain. Patients’ beliefs seemed to be focused around their subjective experience in comparison to the beliefs of general practitioners which seemed to be more biomedical orientated. The reviewed papers suggest that this biomedical approach may be due to their lack of training and awareness in how to manage patients with musculoskeletal pain.

In 2009, Overmeer et al found that physiotherapists held similar views on the cause of pain to those of the general practitioners in the review by Parsons et al (2007).
Overmeer et al (2009) evaluated the views of forty-two randomly selected physiotherapists on the cause of pain by the use of the Pain Attitudes and Beliefs scale for Physical Therapists (PABS-PT). The PABS-PT consisted of two factors one measuring the biomedical orientation and the other the orientation of biopsychosocial treatment.
Prior to attending a severn day educational program the results of the physiotherapists PABS -PT scores suggested that they held beliefs that were more biomedical focused. Compared to after the educational program results favoured a more biopsychosocial orientation towards pain. Despite the study showing a change in beliefs following the educational program the results could be flawed as the physiotherapists attending the course applied voluntarily and were already interested in and had knowledge about and already with some degree begun to adopt a biopsychosocial approach before the course.
What I found interesting in this study was that the majority of participating physiotherapists had over ten years experience. I would have expected them to have had a greater understanding of the biopsychosocial orientation of pain. However, clinical practice changes all the time despite despite the fundamentals staying the same and concepts move forward. We don’t know if the practitioners specialised and if so what in and how long for. The fact that participants signed up voluntarily could suggest they were keen to improve their current knowledge. Also most of the therapists worked mainly in private practice perhaps they adopt a more biomedical approach. Is there less biopyschosocial presenting clientele within private practice than within the National Health Service?

Similarly, a study by Latimer et al in 2004 that measured the attitudes and beliefs of third and fourth year physiotherapy students on adults suffering chronic low back pain, found that following a specialised educational program, attitudes and views changed.
Six hundred and eighteen, third and fourth year undergraduate physiotherapy students completed the Health Care Providers’ Pain and Impairment Relationship (HC-PAIRS) scale. Believed by Rainville et al (1995) to be a highly reliable form of assessment with internal consistency when used to measure the attitudes and beliefs of health care providers to chronic back pain.
Three hundred and five students went on to complete a further scale after a 4 week, 16 hour teaching module.
Although therapy students’ attitudes and beliefs were measured through the HC PAIRS scale, unlike the study by Latimer et al (2000) the orientation of their beliefs was difficult to tell. The short term effects of the teaching module was evaluated through assessing students’ beliefs immediately after the teaching module. Long term effects of the module were evaluated a year on when year three students were in their final year. The HC-PAIRS scores of students not exposed to teaching i.e those that completed the scale but did not go on to attend the teaching module and the year four students that received no specialist training were found to be similar to those obtained by Rainville et al (1995) for a group of community health care providers, that included physiotherapists, occupational therapists, physicians, nurses, and psychologists. Rainville et al (1995) compared the views of community health care providers to a group of pain clinic providers. Community health care providers had a significantly higher mean HC-PAIRS score than those working in specialist pain clinics. This suggesting that like the physiotherapy students, health care providers agree more with the notion that chronic low back pain justifies disability and the limiting of activities.

Smart and Doody (2007) assessed the clinical reasoning processes of severn experienced physiotherapists. The study concluded that all severn of the physiotherapists demonstrated extensive and diverse psychosocial oriented reasoning. their clinical reasoning took into account patients’ cognitions, emotions, behaviours, attitudes andcoping strategies as well as sociological factors. In the same sequence, each physiotherapist viewed three separate videotaped patient – therapist interviews describing three different pain presentations. Their thought processes regarding the nature of the patients’ pain presentation were asked to be verbalised. As each physiotherapist viewed each of the case studies, the principle researcher, a senior physiotherapist conducted a semi-structured recorded interview. At set intervals the researcher paused the video recordings at which point open ended questions were asked to prompt each physiotherapist to verbalise their thoughts. Each of the interviews were transcribed. The transcripts were then coded and their inter and intra coder reliability was checked which was found to be excellent and good retrospectively according to Daly and Bourke, (2000). As all therapists had a minimum of ten tears experience in musculosketal physiotherapy and had engaged in formal postgraduate education this study highlights the difference between inexperienced practitioners knowledge on the understanding and integration of the biopyschosocial pain presentation compared to those who are more experienced and knowledgable. Jensen et al (2000) and Edwards et al (2004) also support better psychosocial orientated reasoning among experienced physiotherapists in their studies that evaluated the clinical reasoning process of experienced clinicians.

With the understanding that there seems to a gap in the knowledge of the biopsychosocial understanding of pain and it’s incorporation into the clinical reasoning process particularly among less experienced clinicians. In the next post I hope to look at how this influences our practice does it affect clinical outcome?

References

Daly L, Bourke G Interpretation and uses of medical statistics. Oxford: Blackwell Science 2000

Edwards I, Jones M, Carr J, Braunack-Mayer A, Jensen GM (2004) Clinical reasoning strategies in physical therapy. Physical Therapy. 84 312-335

Jensen G, Gwyer G, Shephard K, Hack L, (2000) Expert practice in physical therapy. Physical Therapy. 80 28-52

Latimer J, Maher C, Refshauge K (2004) The Attitudes and Beliefs of Physiotherapy Students to Chronic Back Pain. Clinical Journal of Pain. 20 (1) 45-50

Overmeer, T, Boersma K, Main C, Linton S (2009) Do Physical Therapists change their beliefs, attitudes, knowledge,mskills and behaviour after a biopsychosocially orientated university course? Journal of Evaluation in Clinical Practice. 15 724-732

Parsons S, Harding g, Breen A, Foster N, Pincus T, Vogel S, Underwood M (2007) The influence of Patients’ and Primary Care Practitioners’ Beliefs and Expectations About Chronic Musculoskeletal Pain on the Process of Care. Clinical Journal of Pain. 23 91-98

Rainville J, Bagnall D, Phalen L. (1995) Health care providers’ attitudes and beliefs about functional impairments and chronic back pain. Clinical Journal of Pain. 11 287–295.

Smart K, Doody C (2006) The clinical reasoning of pain by experienced musculoskeletal physiotherapists. Manual Therapy. 12 40-49

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