A critical evaluation of the efficacy of Pain Neuroscience Education

Christian Hanssen is a physiotherapist working in Norway studying part-time for the MSc MSK physiotherapy. He has kindly offered for the essay he submitted for the introductory module ‘MSK Physiotherapy: evaluting practice’ to be posted. If you are starting your journey on the MSK course, please note that this essay takes a more formal scientific style than than the other blogs as per the requirements of this module assessment. Here it is:

INTRODUCTION

Within physiotherapy, educational interventions are commonly used in the management of chronic pain and disability. Traditionally, educative models have addressed chronic pain from a biomedical perspective, where unhealthy tissue and mechanical abnormality is explained to be the source of symptoms (Moseley & Butler 2015). These traditional models may have relevance in more acute states after injury, disease or surgical interventions. However, they seem insufficient to explain the complexity of pain and especially chronic pain states (Moseley 2003a). In recent years, physiotherapy has gone through a paradigm shift, moving away from a biomedical model to a biopsychosocial explanation of pain. The biopsychosocial paradigm understands pain as a multifactorial experience, created in an interaction of biomedical factors and psychosocial aspects such as emotions, mood, beliefs and social and environmental aspects (Lumley, Cohen, Borszcz, Cano, Radcliffe, Porter, Schubiner & Keefe 2011). In chronic pain states psychosocial factors may be particularly relevant (Blyth, Macfarlane & Nicholas 2007).

Based on a biopsychosocial understanding, Pain Neuroscience Education (PNE) emerged in the early 2000s not only as an educative treatment itself but also as a theoretical concept on how to approach chronic pain (Moseley & Butler 2015). Other terms such as explain pain, pain education and neuroscience education are used within the literature (Moseley & Butler 2015). For this essay Pain Neuroscience Education, often abbreviated to PNE, will be the preferred term. The shared aim of all these educative interventions is to reconceptualise patients’ understandings and beliefs of pain (Moseley & Butler 2015). It focuses on teaching what pain is, its function and its biological underlying mechanisms (Moseley & Butler 2015). Patients with chronic pain may explain their symptoms from a structural biomedical point of view (Baird & Haslam 2013), while psychosocial factors may be of particular relevance (Nichols, Linton, Watson & Main 2011). PNE emphasizes pain rather as a perceived need to protect tissues in the body, separating pain from nociception (Moseley & Butler 2015).This perceived threat is context-specific and influenced by various factors. The goal of PNE is to shift away from understanding pain from a structural and anatomical point of view and from it being a reliable indicator of tissue damage (Moseley & Butler 2015). Moreover, this reconceptualisation intends to challenge previous held knowledge so that a new understanding is adopted (Moseley & Butler 2015). There is an emphasis on “deep-learning” so that the material is fully understood and the pain understanding is reconceptualised (Moseley 2003a).

 

PNE does not come with specific steps or procedures to follow. This becomes evident in the literature through various ways of presenting the material. In the literature PNE has been applied to various conditions and the efficacy on various outcomes has been investigated. PNE has been investigated in relation to healthcare utilization, pain, disability, movement and cognition. I will in this essay limited my focus to pain, disability and psychological aspects, as these areas are dominant within PNE (Moseley & Butler 2015) and also relevant to clinical practice.

The aim of this essay is to critically evaluate the efficacy of Pain Neuroscience Education (PNE) on patient reported measures of pain, disability and psychological aspects in patients with chronic pain.

 

PAIN AND DISABILITY

Pain and disability can have a major impact on quality of life, (Breivik, Collett, Ventafridda, Cohen & Gallacher 2006) and is one of the main reasons why people seek help from the health care industry (Hasselström, Liu‐Palmgren, & Rasjö‐Wrååk 2002; Mortimer & Ahlberg 2003). It is therefore important to consider the effect PNE may have on pain and disability. In the included literature, terms as “disability”, “physical function” and “function” are used when referring to the same outcomes and outcome measures. In this essay disability will be the chosen term. PNE is in the literature utilized for a range of conditions, but a large proportion is done on chronic low back pain. Clarke, Ryan & Martin (2011) present evidence that PNE can reduce patient reported pain and disability in the short term. They have investigated the efficacy of PNE on chronic low back pain. This was allegedly the first review on PNE and included two RTCs. One compared PNE alone to biomechanical education. The other did a comparison of PNE and a pain management programme to pain management education, based on the Back Book (Martin 2002). In both studies, PNE was based on the book Explain Pain (Butler, Moseley & Sunyata 2003). While the former obtained outcomes only at short term (below three months), the latter also obtained at medium (three to six months) and long term (12 months). Both RCTs measured pain by a 100 mm Visual Analogue Scale, whereas disability was measured by different tools. One used Roland Morris Disability Questionnaire, whereas the other used Patient Specific Function Scale. Due to differences in measurement tools and follow up-periods, combination of results was only possible for pain at short term. This combination showed a significant difference favouring PNE, however not of clinical significance. Measures of pain at medium and long term were at both time points of statistical and clinical difference in favour of the PNE-group. Results with regards to disability at short term were in both studies in favour of PNE. In one of the studies, there was a clinically meaningful difference between the groups at this time point, this was however because of a negative score in the control group. At medium and long term, the combination of PNE and pain management against the control group was in favour of PNE at both time points. These results were not of statistical difference. However, the two studies together only include 122 participants. Therefore it can be questioned whether they were sufficiently powered to detect statistical differences. Further on, the fact that both studies are done by the same author who also co-authored the PNE manual is a potential bias. The author may have economic interests in proving PNE useful. In addition, one of the studies was not published in a peer reviewed journal, but was a conference paper. Overall, the results this review suggests effect of PNE mainly on patient reported pain in the short term for patients with chronic low back pain. The ability to affect disability is uncertain. Lastly, methodological limitations weaken the internal validity which also weakens the external validity and generalisability.

Promising results of PNE for chronic low back pain is also supported by a recent study. In a single-blinded RCT, PNE and exercises was compared to exercises alone (Pardo, Girbés, Roussel, Izquierdo, Penick & Martín 2018). 56 participants with chronic low back pain were randomized into two groups. At baseline and after one month, both groups received instruction in stretching, aerobic and motor control exercises. One of the groups received in addition education based on the book Explain Pain (Butler et al 2003) and content from Pain In Motion (www.paininmotion.be) at these same time points. These two educative sessions lasted each 30 – 50 minutes and was presented in groups of four to six people. The primary outcome of the study was pain rated on Numerical Pain Rating Scale. Disability was also obtained as secondary outcome measured by the Roland-Morris Disability Questionnaire. By the end of the three month follow-up period both groups experienced improvement on the Numerical Pain Rating Scale and the Roland-Morris Disability Questionnaire. Combining PNE with exercise however, gave a statistically and clinically better outcome than exercise alone with a large between group difference for both outcome measures (p <0,001). A very high compliance was seen in the study and the authors point out that they could have selected particularly motivated people as the participants took contact to participate in the study. Based on this, it may be discussed whether the sample is representative of the population of patients with lower back pain. One may question if patients who on their own initiative participate in study is more dutiful than those who did not sign up. Socio-demographic conditions, such as educative level and employment, were not recorded. To sum up, this study presents evidence that PNE combined with exercise provides statistically and clinically significantly better outcomes for patient reported pain and disability in the short-term, for people with chronic low back pain, compared to exercise alone. Nevertheless, the long-term effect is unknown and it is uncertain to which patients with chronic low back pain the findings are relevant.

The ability of PNE to improve short term outcome of pain and disability is also supported by a larger review. Louw, Zimney, Puentedura & Diener (2016) have conducted a review on PNE and musculoskeletal pain, including 13 RCTs. In ten of the studies outcomes related to pain were obtained. 12 studies include outcomes related to disability. Across the studies a range of measurement tools were used to obtain these outcomes, there were five different tools for measuring pain and eight for disability. Therefore the results were not pooled, but presented in a narrative way. The authors labelled an outcome as positive if the group who received PNE achieved a significantly better change than the control group. If there was an insignificant difference or if the intervention group had significantly worse results, the outcome was respectively labelled as neutral or negative. Outcomes related to pain were in the review grouped into measures of pain rating or pain tolerance. Regarding pain rating, PNE compared to the control group gave a positive result in five of eight studies. A positive result was seen in one of three studies including pain tolerance, and outcomes of disability showed a positive result in six of 12 studies. The groups receiving PNE never came out significantly worse than the control group. Thus in several of the studies no significant difference in pain rating, pain tolerance and disability between the groups was noted. Several noteworthy aspects of the results are worth pointing out.  As PNE never came out worse than the control group, there seems to be a low risk associated with PNE implying a beneficial risk-benefit ratio. In several of the studies, PNE was combined with active and/or passive interventions. Thus, one can question if it is PNE, PNE combined with active and/or passive interventions, or the active and/or passive interventions that has had effect. The results showed that PNE came out more effective when given in combination with other interventions. In five studies PNE was given in isolation, and none of them reported significant reduction in pain ratings. Interestingly, the majority of studies which combined PNE with active and/or manual interventions report significant reduction in pain ratings compared to the control group. The authors discuss whether education in alone may not be sufficient for change. On the other hand, one does not know whether it is the other interventions that have given effect. The results of the review are strengthened by its relatively high number of participants, overall there were 734 participants. This is higher than previous reviews on PNE, like the review of Clarke et al (2011). Further on, the review by Louw et al (2016) only contains RCTs, which all scored 6/12 or more on the PEDro scale. However, there are several aspects that must be taken into account. The review includes a diverse population. Although the majority of studies included were performed on chronic low back pain (seven of 13), various conditions as neck pain, fibromyalgia, chronic fatigue syndrome and preoperative radiculopathy were also included. Furthermore, the PNE sessions were carried out individually and in groups, and a variety of teaching aids have been utilized, such as booklets, power points and verbal explanations. Moreover, the number and duration of the education vary from a single session of 30 minutes to four sessions of one hour. In addition, the content of the education vary across the studies. The content of the control groups also vary. Louw et al (2016) concludes that there is strong evidence that PNE can decrease pain ratings and disability. At the same time, it is difficult to conclude how PNE should be implemented, as the variation within interventions is high. Lastly, it is worth noting that only three studies report outcomes after one year, two studies at 6 months while the rest had follow up periods of three months and less.

Based on the included literature, there is evidence to support the ability of PNE to reduce patient reported pain and disability particularly in the short term. PNE comes out more effective for patient reported pain when combined with other interventions. Most of the research is done with short follow-up periods which limit the ability to make conclusion regarding the long-term effect of PNE for these outcomes. Although most of the research is performed on patients with chronic low back pain, PNE is utilized for a range of conditions with various ways of presenting the educative material. This makes it difficult to conclude how PNE should be implemented.

PSYCHOLOGICAL ASPECTS

In this section, PNE and its ability to affect psychological aspects of chronic pain will be addressed. One of the principal goals of PNE is to change and reconceptualise someone’s thoughts and understanding of pain (Butler & Moseley 2015). This is important considering that adverse attitudes, beliefs and catastrophizing can be linked to chronic pain (Linton & Shaw 2011). PNE and psychological aspects have been studied in several conditions, but also here most of the research has been done on chronic low back pain. There is evidence to support that PNE can change adverse thoughts and beliefs about pain in short term. In a previously mentioned single-blinded RCT, involving 56 participants with chronic low back pain, Pardo et al (2018) also obtained Pain Catastrophizing Scale and Tampa Scale for Kinesiophobia as secondary outcome measures. By the end of the three month follow up, both the group who received PNE and exercise and the group with exercises only demonstrated reduced catastrophizing and kinesiophobia. The group receiving PNE demonstrated, however, a significant decrease in both pain catastrophizing and kinesiophobia compared to the other group. The statistics describes a large between group difference favouring PNE group for both outcome measures (p <0,001). A very high compliance was seen, and as noted previously, one may question if the study is limited by a selection bias.

Other studies also present evidence in support of the ability of PNE to affect psychological aspects of chronic pain. In the previously mentioned review by Louw et al (2016) they report positive effects of PNE on psychological outcomes. The authors conducted their review on PNE and musculoskeletal pain and outcomes related to psychological function were obtained in 11 of the 13 included studies. Overall, eight different tools to measure psychological outcomes were utilized. Because of this heterogeneity results were presented narratively. Results were labelled as “positive”, “neutral” or “negative”. A positive label was given if the intervention group including PNE achieved a significantly better change than the control group. Likewise, the results were labelled negative if the intervention group had significantly worse results and neutral if there was an insignificant difference. As presented in table 1, the group who received PNE came out with either an insignificant difference or significantly better result regarding psychological aspects than the comparing group. Thus, PNE does not have negative effects on psychological aspects of chronic pain, which indicate that PNE can be safely applied. Nevertheless, as noted previously, it is difficult to specify to whom the findings can be generalized to, as different diagnostic groups are included. Furthermore there are differences related to the content, duration and number of PNE sessions. Moreover, as only three studies had follow up periods of more than six months, the review provides limited knowledge about the long term effect of PNE on psychological aspects. In sum, PNE seems to be a safe intervention and demonstrates an ability to change adverse thoughts and beliefs of pain in the short term.

Table 1: The effect of PNE on psychological outcomes in patients with musculoskeletal pain (n = number of studies*)

OUTCOMES	RESULTS Positive          Neutral            Negative
Reduce fear of movement (n = 7)	3	4	0
Pain catastrophisation (n = 5)	3	2	0
Pain coping strategies (n = 2)	0	2	0
Pain attitudes (n = 3)	2	1	0
Anxiety and depression (n = 1)	1	0	0

*Summary of results in the review by Louw et al (2016).

 

The ability of PNE to affect psychological aspects of pain has also been investigated with a qualitative approach. King, Robinson, Ryan & Martin (2016) have investigated how beliefs and attitudes towards pain may reconceptualise after being presented with PNE. Seven patients with chronic musculoskeletal pain completed the study involving a two hour group-lesson based on the book Explain Pain (Butler et al 2003), and took part in a semi-structured interview one week before and three weeks after receiving PNE. The data from the interviews was analysed thematically using an Interpretive Phenomenological Analysis. Through this analysis, three themes emerged. The first theme was related to the patients having a varying degree of reconceptualisation. Some displayed a change from biomedical terms to language more in line with PNE. Others, on the other hand, continued to use clear biomedical terminology also after the PNE session. The second theme referred to how previous beliefs could affect the change. Those who had a strict biomedical language in the first interview were more prone to use similar language in the second interview. Lastly, the third theme related to how pain reconceptualisation was linked to individual experiences of improvement in pain, function and wellbeing. Those who displayed a change in beliefs and attitudes towards a biopsychosocial understanding reported PNE to be more meaningful to their own situation and symptoms. This study provides information into how patients understanding of pain may or may not change after receiving PNE. These findings have clinical relevance as it display that individual differences in patients with chronic pain affect their degree of change. Patients are unique with individual pain narratives, attitudes and beliefs. Therefore presenting PNE in the same way to all patients may not be suitable. This implies a need for individual tailoring of PNE. At the same time, it should be noted that the findings are based on a small sample, seven participants. Further on we have little information about the sample, except the fact that they have chronic musculoskeletal pain. The authors however note that these findings should be regarded as illustrative rather than representative, which is in line with the aim of qualitative approaches (Polit & Beck 2012).

Overall, the included literature presents evidence that PNE can positively affect psychological aspects of chronic pain in the short term. Individual differences between patients can influence the degree of change. The research on PNE is conducted with short follow up periods, with a varied population and a varied way of presenting the educative material. This limits the ability to conclude how PNE should be implemented and its potential long term effect on psychological aspects of chronic pain.

CONCLUSION

The included literature presents evidence that PNE can decrease patient reported pain and disability and have a positive impact on psychological aspects of chronic pain, in the short term. PNE has in several studies shown to be more effective on patient reported pain when given in combination with other interventions. A large part of the research has been conducted on chronic low back pain with short follow-up periods, there is, however, a great variety within the literature related to diagnoses, the delivery and content of PNE and the number and duration of the educative sessions. Because of this heterogeneity, there is limited ability to conclude for which diagnoses PNE is most effective, its potential long-term effect and how PNE should be implemented. Furthermore, there is a need for individualization of PNE in order to make it relevant to the each patient.

REFERENCES

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Breivik, H., Collett, B., Ventafridda, V., Cohen R. & Gallacher D. (2006). Survey of chronic pain in Europe: Prevalence, impact on daily life, and treatment. European Journal of Pain, 10(4), 287-333.

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