“Pain Is In The Brain” – Is It A Load Of S**T?

 

“Pain is in the brain” is by far and away one of my least favourite phrases and in my opinion unhelpful in understanding a modern view of pain.

Why….?

Well, there are a number of reasons.

  1. It implies (to me anyway) it is not IN the body. This for many people is tough to get their head around, and rightly so.
  2. This may also imply that it is “all in my head”. Again not a helpful message for many and could potentially create more problems than it attempts to solve.
  3. Has created polarisation. As pain obviously has a good part of its genesis within the body we now get the “pendulum has swung too far” fight back. This is a completely warranted stance against this argument. The problems potentially lie in the perception of those who think that anyone who believes the brain is a major player in the pain experience is suggesting pain is all “in the brain”. It is easy to create a counter-argument against a polarised opinion.
  4. That it is idiopathic and spontaneously erupts. Whilst this may be true in some isolated cases for many it is a maladaptation of the system in response to a more physical Genesis.

 

Human brain

 

PAIN IS AN OUTPUT OF THE BRAIN

‘Pain is an output of the brain’ seems a much more sensible way to explain the pain process in my opinion. This allows a model that incorporates both inputs from the body and a modulation of that input in the brain.

The more pain persists then the more it may be driven by top-down rather than bottom-up influences although we must remember that we can get changes, or plasticity, in the nociceptive (noxious stimulus) or danger processing system further down the chain in the periphery and the spinal cord as well.

Stimulus (danger!) processing within the brain can actually be used to turn the output or emergence of pain down as well as up. We have cleverly named ‘on’ and ‘off’ cells in our rostral ventromedial medulla (RVM) that do just that. ‘Off’ cells exert descending inhibition on nociceptive transmission while ‘on’ cells facilitate it.

‘PATHOLOGICAL’ PAIN

There does seem to be situations where pain itself becomes more of a pathological process. Phantom limb pain is an example where potentially the mechanism for pain is more about the representation of the limb in the brain than nociceptive signals from the limb and is very prevalent with amputees at between 60 & 80% HERE it is also worth reading Melzack and Katz’s opinion on this HERE.

Harris has suggested incongruence between motor intention and movement as a source of pain HERE and sensorimotor incongruence exacerbates the pain of chronic whiplash sufferer’s HERE although this is not a consistent finding HERE.

Moseley & Valyaen HERE and Zusman HERE have both proposed coupling between proprioceptive information, pain responses and memory within the brain that no longer requires nociceptive input from the body.

HERE we see that the visual distortion of a limb can actually affect the processing of pain!

These pieces of research and theory help us understand that pain is a complex process and a ‘pain’ signal is not just simply relayed from the body but it also does not mean that pain is only ‘in the brain’.

So if someone was to ask “is pain in the brain?” My answer would be no, it is much more likely that it is a complex interplay between bottom up and top down influences modulated by many factors and that the sensitivity of the systems involved in the experience of pain has the potential to change over time at peripheral, spinal and cortical levels.

SEMANTICS

Some might, and have, suggested that this is simply semantics. I would agree completely with this because semantics matter. How people interpret meaning is a huge great big deal when it comes to pain and to not recognize that is a problem. This is a great paper by Darlow HERE and another by Barker HERE

‘Pain is in the brain’ seems open to being misconstrued by those in pain and also those who realize it has a great deal of its genesis within the body too.

IS THE ‘ISSUE IN THE TISSUE’?

Is the ‘issue in the tissue’?

Well, of course, it can be, just sometimes a bit more and sometimes a bit less. This does not mean there has to be a pathological state of the tissue however or if there is that getting better is contingent on a change in the state of the tissue. HERE & HERE.

Although we are realizing that pain and damage are not one and the same, local biochemical processes are likely to be very much at play. Whilst there may not be pathology we may have a pathophysiological process occurring, this being a physiological process that has gone a bit haywire!

An example might be if I go out and run a bit more than my body is used to and the normal reparative processes, such as tissue regeneration, becomes replaced by a different cellular expression such as pro-inflammatory chemicals like neuropeptides. This has been documented with tenocytes (fibroblastic like cells) as they transduce mechanical force (mechanotransduction) into cellular processes such as the expression of substance P potentially creating a peptidergically driven inflammatory state in the tissue HERE and HERE we see an elevation of substance P in vivo in response to load.

So we may have a situation where the local tissue state is chemically sensitized due to activity, perhaps previously under loaded tissue and this could potentially be turned up by changes in sensitivity in the systems involved in pain peripherally, spinally or cortically dependent on individual previous pain experiences.

PHYSICAL CHANGES IN THE EXPERIENCE OF PAIN

Changes in the systems involved in the emergence of pain don’t have to be ‘in the brain’ either. The subcortical bits can play their role too with actual physical changes occurring to the peripheral nervous system (PNS) within the tissue. These changes to the PNS include an increase in the number of ion channels in the terminal endings of nociceptors making it easier to get sodium ions into the cell, depolarise it and send a signal (action potential) to the CNS. We also see an increase in the number of receptors and previously silent receptors becoming active.

The signal processing at the dorsal horn can also be ‘turned up’ with more NMDA/AMPA channels making it easier for the peripheral signals to be sent up the chain and an increase in excitatory neurotransmitters, such as glutamate and aspartate, and a decrease in inhibitory chemicals such as GABA and endogenous opioids.

We can also get long-term potentiation of spinal neurons in response to repetitive stimulation or a sustained ‘volley’ of signals from the C-fibres.

Basically put, the more noxious stimulus we receive the more sensitive the dorsal horn becomes to it.

HAS THE PENDULUM SWUNG TO FAR?

That probably depends on your bias and opinion but if someone was to suggest that pain is solely ‘in the brain’ then I would suggest yes it has!

An inclusive model that allows physical, physiological, neurological and psychological processing changes probably fits with what we know about pain at this point in time. Sometimes the pendulum may have to swing big firstly to overcome the inertia of previously held beliefs and then hopefully comes to rest somewhere in the middle.

Motivational Interviewing In Your Clinic

A great deal of our work as therapists involves helping people to make changes in order to get better outcomes, be it for general health and well-being, reductions in pain, or increases in mobility.

Our training and education means that we know a lot about what people need to do to achieve these outcomes. We are smart and we know it! We assume the patients coming in to see us, know that too. So it should be simple right, we tell them all the things that they need to know, and they go away and do it. But here lies the problem, no one really wants to be told what to do.

Take for example the person who has recently had a heart attack but is also a smoker. They are very likely to be informed of the fact that continuing to smoke is going to contribute to poor health outcomes including increasing the risk of another heart attack. With such a frightening near death experience, one might assume that being given sufficient information, combined with the fear of the experience would be enough to make someone stop smoking.

However the studies tend to tell us that only about half the people in this situation will actually quit smoking! (1) Mind blowing isn’t it? What this and many other studies in similar fields of healthcare continue to show us is that information and fear are not enough to change behaviour, no matter how dire the consequences. (2)

Changing Our Approach For Better Outcomes

Self management forms a big part of the picture in managing all chronic diseases. As we start to view pain with a more modern and science based understanding, our approach to treating it should start to shift away from trying to “fix” the patient and towards an empowering model of care that encourages the patient to take their health into their own hands.

Sounds easy doesn’t it?,  but many of us have been experiencing as practitioners what an uphill battle this is. Particularly in our western culture where there is an understanding around medicine being able to “fix” everything, so that the mere presence of pain is viewed as being “wrong”, and the understanding that as a consumer based system,  you just have to pay for the “thing” (manual therapy/ acupuncture/ surgery/ injections etc) and it will be done to you and will be effective.

Unfortunately, we know it doesn’t work like that.

Single modality approaches for treating any pain condition, but particularly chronic pain, are largely unhelpful in the long term and science tells us that adopting an active approach is far more likely to lead us to better outcomes. (3)

In treating pain and getting people to adopt behavioral change, some of the information we provide to help, might be of a therapeutic neuroscience education (TNE), explaining pain, pain education approach. Along the lines of what we see in situations like smoking cessation, weight loss and exercise programs, providing the information doesn’t always translate through to the outcomes we might hope.

That is not to say that we don’t use it.

The research tells us it has value (4-7) , we just understand that it is one part of the process, the information and context a person might use when deciding on taking a multidisciplinary and active approach to treating their pain.

Motivational Interviewing

Motivational interviewing is a cognitive behavioral technique that helps patients to identify behaviors that may be preventing them from achieving optimal management of a chronic condition. It has been used in many healthcare settings which require behavioral change for better outcomes such as addiction medicine, oral-health self care, smoking cessation, weight loss, medication compliance and diabetes self management. It identifies a cycle that people tend to go through (and often go back around and around) in processing a change in behaviour.(2)

 

The process of motivational interviewing is one that provides structure around helping a person to find their own motivation, the idea being that if a person has made the choice for themselves they are far more likely to follow through with change, compared to when it is something that has been forced upon them.

It is a process that requires first establishing a level of rapport with the person and then helping them to identify what behaviors they would like to change. Within the approach there are some specific techniques that can help the practitioner to elicit in the patient a better understanding of what his or her thought processes are in relation to the problem. Then through a process of reflective listening and open ended style questioning, helping the person to identify how important the change is to them and how confident they are in being able to make those changes. From there a structured, but collaborative approach can address the barriers to change, identify measures of support and create a plan to move forward that fits with the patient’s own motivation.

The best thing about motivational interviewing is its accessibility. It is a process that has been used in industries other than just psychology, (sales and human resources to name a few). This means that it is easy to learn about it and that applying it in the clinic is not an “all or nothing principle”.

You can start to learn about some of the elements and apply them straight away – the easiest way is to refine your listening and reflecting skills and resist the urge to jump in straight away and tell people what they “should” be doing. There are lots of resources available in the form of short courses, blog post summaries, books and journal articles. So if you are feeling motivated, get your google on and work out what your next best step is to start delving into some motivation interviewing skills! (2)

 

References:

1. van Berkel TF, van der Vlugt MJ, Boersma H. Characteristics of smokers and long-term changes in smoking behavior in consecutive patients with myocardial infarction. Prev Med 2000, Dec;31(6):732-41.
2. Bundy C. Changing behaviour: Using motivational interviewing techniques. J R Soc Med 2004;97 Suppl 44:43-7.
3. O’Keeffe M, Purtill H, Kennedy N, Conneely M, Hurley J, O’Sullivan P, et al. Comparative effectiveness of conservative interventions for nonspecific chronic spinal pain: Physical, behavioral/psychologically informed, or combined? A systematic review and meta-analysis. J Pain 2016, Jul;17(7):755-74.
4. Louw A, Diener I, Butler DS, Puentedura EJ. The effect of neuroscience education on pain, disability, anxiety, and stress in chronic musculoskeletal pain. Arch Phys Med Rehabil 2011, Dec;92(12):2041-56.
5. George SZ, Childs JD, Teyhen DS, Wu SS, Wright AC, Dugan JL, Robinson ME. Brief psychosocial education, not core stabilization, reduced incidence of low back pain: Results from the prevention of low back pain in the military (POLM) cluster randomized trial. BMC Med 2011;9:128.
6. Van Oosterwijck J, Meeus M, Paul L, De Schryver M, Pascal A, Lambrecht L, Nijs J. Pain physiology education improves health status and endogenous pain inhibition in fibromyalgia: A double-blind randomized controlled trial. Clin J Pain 2013, Oct;29(10):873-82.
7. Moseley GL. Evidence for a direct relationship between cognitive and physical change during an education intervention in people with chronic low back pain. European Journal of Pain 2004, Feb;8(1):39-45.