Sunday, May 13, 2012

Book review: "The Graded Motor Imagery Handbook"

With the release of The Graded Motor Imagery Handbook this spring, Noigroup (Neuro Orthopaedic Institute) takes itself, and by extension, the physiotherapy profession, out of “tissues”, past the foramen magnum, and into the brain, which provides (at least to this PT reviewer) a bridge across the Cartesian chasm that long ago divided the branch of the profession which considers itself “Neuro”, from the one that considers itself “Ortho”; this bridge is built from fifteen years of deep Noigroup marination in neuro and pain science and education.

It’s a team effort, coauthored by G. Lorimer Moseley, David S. Butler, Timothy B. Beames, and Thomas J Giles; it manages to deliver complex material with whimsy and friendliness. The book’s size, shape, font, flat spiral binding, colourful chapter and page layout, and artwork, engage the reader, and make the content seem much less daunting to study and learn. In a mere 143 pages, The GMI Handbook ambitiously (and successfully) tackles multiply-leveled objectives:

1. Introduce and explain the entire topic to clinicians and patients;
2. Explain why the topic deserves attention, understanding, and implementation by clinicians and patients;
3. Provide a conceptual trail;
4. Provide products, services and support to clinicians and patients to implement the program.

We are given an introductory tour of the book by Butler, who, as an adult educator as well as a longtime PT, speaking to both practitioners and patients, admits this is new territory for PT; although the navigating map may still lack fine detail, he is confident that clinical reasoning should suffice to keep us on track, and his enthusiasm for exploring and charting this new frontier is contagious.

Patients who have persistent, non-medical pain, he explains, need to “exercise their synapses,” lubricate them with knowledge, first; then, subsequently, moving their physicality may feel easier. All behaviours occur within a given context, defined as “the temporary environment of an action or planned action”:

“Knowledge is a very special context. It can be de-threatening, give meaning to your symptoms, provide explanations, help with compliance, allow problem-solving, link to future goals, allow progression of treatment and it can be passed on to other people like a useful virus.” - [p. 7]
Knowledge can be superficial or deep; a new idea will challenge many old ideas, may jostle them aside somewhat. A learner (such as a person with persistent pain) who is prepared for this, will be able to entertain options for moving old beliefs aside, permit new information to enter safely and deeply into his or her own brain, so that it can help change the overall synaptic structure of the brain itself - the ultimate goal is to provide one’s brain with new options based on new information, so that it may eventually change its pain production and pain perception.

The second chapter by Moseley lays out the map of this new territory in as much detail as the book allows for. He recounts his personal journey toward this frontier, reading Ramachandran, meeting Butler, becoming interested in mirror therapy. He explains ‘neurotags’, defines them as, “a network of interconnected neurons..distributed throughout the brain. When a neurotag is activated it produces an output. The output defines the neurotag” [- p 24].

The neurotag is not the bread you smell: it does not produce the odour itself, does not detect it. The neurotag is not the neck pain you feel: it does not produce the neck pain, nor does it detect it. The neurotag is the experience of smelling the bread, the experience of feeling the neck pain. In other words, it is not primary sensation - it’s a kind of “learning” that has occurred by natural synaptic connection. A neurotag will activate when a threshold is reached, and when its member brain cells fire in concert, with no non-member cells firing at the same time. A ‘sensitized’ neurotag for experiencing pain is conceptualized as one whose activation threshold is too low, and whose nearby non-member neurons are too inactive, and therefore don’t or can’t contribute to inhibition.
For most people with pain, actual movement hurts. Without practice, parts of the brain that produce movement have become underused, and their synaptic strength has started to degrade. Primate brains are visually dominant. Humans are primates. Therefore, visual systems are recruited to assist - hence the term, graded motor imagery.

“Explicit” graded motor imagery is imagining yourself moving a body part. In the third chapter by Tim Beames, it is defined as a “process in which you are aware of yourself thinking about what you are doing” [-p. 79]. Through careful data collection, the researchers found out that this could still activate pain neurotags in some people (ouch, not good.) This means, for some people, even just imagining a movement can make their pain feel worse.

So the researchers proposed, and found, a way to get around that: “IMPLICIT” graded motor imagery is a delightfully sneaky process whereby movement-producing parts of the brain can be helped to rehabilitate, their neurons can be excited, but without activating any “pain” neurotags in the process!

The first stage is to help the brain relearn how to make left and right judgements about body physicality, both position of part itself, and various positions of various parts in space. Implicit motor imagery, or right/left judgment, activates pre-motor areas of the brain, which can then excite motor cells, but doesn’t directly activate them. The hypothesis is, that exposure to and engagement with implicit motor imagery can thereby sneak some learning in under the sensory-motor radar, so to speak, help the brain build the synaptic strength needed to undermine, inhibit and dampen the pain neurotag, because it can secondarily excite the motor area without activating either it or its connected pain neurotag! The brain will gradually and naturally tilt toward greater efficiency of inhibition, especially if it thinks changing is its own idea, that the change is coming from within instead of from without.

All of this sheds fascinating light on the “locus of control” aspect of brain function. It is a clever set-up indeed that can move locus of control around, and back and forth, right inside a brain!

Moseley has taken Melzack’s neuromatrix model of body-self a step further in his work, introducing the idea of a cortical body matrix, which integrates not just maps of the body, but also its surveillance, proprioception, regulation and protection, and not only the body - but also its surrounding space as well! The ‘cortical body matrix’ comprises a ‘network of networks’ - it includes “the suite of body systems that can be disrupted in a range of neurological and psychiatric conditions, including chronic pathological pain” [- p. 35].  He says that bias away from the “painful” side of the body includes a bias away from the space occupied by that part, as well; i.e., the brain prioritizes ‘away’ from the “painful” space. Delayed response time judging one side compared to the other led to this idea. Why the brain does this is as yet unknown; Moseley suspects the brain’s body-space maps may be disrupted somehow, although he isn’t fully committed to that idea quite yet.

Patients who embark on a course of implicit motor imagery training are counselled to enjoy the journey, not rush toward the destination - they are asked to develop and engage patience, persistence, courage and commitment. Possible pitfalls and obstacles are mentioned in the book, plausible explanations put forward.

The main tools for implicit motor imagery training are sets of cards depicting body regions and parts in various positions. The term “vanilla image” appears without warning on p. 45, without definition. (One must wait until chapter 5, p. 134, to learn from Tom Giles that “vanilla” refers to a “basic” image, on plain coloured background, without context, but one in which the body part has been randomly rotated 90, 180, and 270 degrees.) The patient is started with “basic” (unrotated, plain background) images, then “vanilla” images, and eventually moves to images of body parts inside a given context, i.e., how they might appear in magazines etc. The task is to decide as fast as possible, based on a quick glance only, if one is looking at a right or left side, or hand, or foot, etc. Scores improve over time as the brain’s synapses find each other after repeated exposure, and start to hook up. 

Figure 3.1 Flowchart showing ideal sequential progression of the different elements of graded motor imagery (GMI). From p. 61, The Graded Motor Imagery Handbook 

The third chapter by Tim Beames is a “nuts&bolts” description of the implementation of the program, outlining several how-tos, and what-ifs. Explicit motor imagery is a way of practicing a motor skill or activity which engages the brain parts involved, including the motor cortex, but without actually physically performing the motor actions - exercising the “virtual” body but not the physical one. The inner regulation control systems don’t really know the difference though - heart rate may respond to the imagined movement by increasing, for example. Patients graduate to this, and to mirror therapy, which involves the actual motor cortex to produce real movement, once they have successfully navigated implicit motor imagery, and have improved their right-left judgement scores. Graded exposure and pacing tips are woven throughout. Case studies are described. The goal is not just pain relief - the goal is to help the patient’s brain regain flexibility and creativity!

Butler returns in Chapter 4 to discuss stories, images and metaphors that can help move the process along.

In Chapter 5, Tom Giles explains how to set up a “Recognize” program on the computer or as a mobile app., essential aid to clinicians who want to integrate this whole system into a busy practice, or to patients who need to access it any time of the day or night.

I think prior exposure to neuroanatomy would be helpful, so I am including in this review an image I like very much from Mayo Clinic Medical Neurosciences 5th edition, depicting how inputs funnel themselves within the brain, from afferent sensory systems to output systems, premotor, and motor cortex. 

Fig. 16B.11 Hierarchical processing of information in cerebral cortex. From p. 713, Mayo Clinic Medical Neurosciences, 5th Ed. (2008) Benarroch EE et al., Informa Healthcare 

I would have appreciated having “vanilla image” explained earlier in the The GMI Handbook, or appear in the index, but I can also understand how individuals in a group, working feverishly on a project, may understand perfectly well what each other means and completely overlook the fact that no one outside the group may know what they mean by a certain word. (That is really my only negative criticism, and it’s a pretty small one!)

Overall this book is a pleasure to look at, handle, read, and use. It represents expansion of the profession beyond its ordinary knowledge base, providing hope to all clinicians who may be dissatisfied with the tools we were taught based on information that is no longer relevant, and to patients who want their practitioners to learn something new that might help them recover their own neural and movement capacities, and hopefully help their brains unlearn pain!


Neil Pearson said...

I think that this is a great book too. I have not read it through carefully yet, so it is possible that some of this comment is related more to this blog than to the book.
I wonder how much we need to get in 'that far under the radar'. When we educate people, we do not know how many of them are okay starting with the idea that their beliefs about pain are wrong. Certainly many have sort of figured out that 'it doesn't make sense' and that this might mean that their beliefs are not accurate. Others have been trained to stubbornly hold on to their beliefs.
For GMI, we do not know that we need to go in with limb laterality work first, using recognise. There is excellent research showing this is very much needed in people with CRPS. Yet we know that brain and body changes are different in CRPS, so do we need Recognise for that many people? Sort of akin to this question, do we need a capnograph to help everyone with latered breathing related to their pain?
The authors provide a sound theoretical premise, which no doubt has truth, and PTs will treat as absolute truth. I think we need to remember that the clinical outcomes we find with this process, do not necessarily support the theory.
My belief is that many people can start with explicit GMI. We need to look to the motor learning research that shows us there are grades of neuromatrix engagement within different types of explicit GMI. Start everyone on the more advanced motor imagery typical of a high diver and we get loads of nervous system engagement - that could crank up the pain. Use either kinesthetic, 1st person visual or 3rd person visual imagery and you get different levels of engagement, and aften we can find ways to not engage the neurotag with these. The other intersting idea of course would be to compare whether using Recognise would provide superior results to a intervention based on the same concepts, and without this technology.
Equally important, it is possible that Recognise's positive impact works through a process not quite related to 'getting in under the neurotag radar'. Maybe Recognise reconnects the individual to a more normal body awareness and body image. Pain distorts these, and there is evidence that improving them in the face of pain is not only possible but is correlated to positive changes in the pain. Maybe if we are more able to experience our body and its physiological state, the neurotags are less activated when we attempt explicit motor imagery.

Of course, not that I state all this, I want to reaffirm that this is an excellent book. It is innovative and hopefully makes one think more than mindlessly follow the intervention process - whichh of course is one that has excellent clinical validity even for a clinician who doesn't quite buy the theoretical premise provided.
I bought one for me, and one for the clinicians with whom I work!

Diane Jacobs said...

Thank you for those thoughts Neil.
Meanwhile, on the topic of the relationship of thoughts to movement, there is this new development:

vyapada said...

My (simplified) understanding of their work (reading papers, not book) was that a single patient had difficulty with explicit motor imagery and therefore implicit motor imagery was developed. A patient I treated with who was suffering from CRPS had no difficulties with explicit motor imagery... I agree with Neil that we should treat our patients as individuals and assess appropriate interventions and not merely stick to programs. Perhaps some may benefit from immediate mirror box therapy?

Diane Jacobs said...

Thank you for your comment vyapada. I'm sure the authors would not disagree with either you or Neil. Perhaps one of them will come by to comment directly.

I would like to mention that in preparation for writing this review, I casually googled "graded motor imagery" and learned that there were 19,500 papers available on the topic in Google Scholar, and was suitably impressed. A profession which calls its members 'movement specialists' clearly needs to become aware of and more conversant in GMI. In my opinion, NOIgroup is helping to move the whole profession forward by investigating GMI from a PT application point of view.