Tuesday, May 27, 2014

Therapeutic Neuroscience Education: finally, a book that says it like it is.

I fall asleep every night after reading a few pages in Therapeutic Neuroscience Education. I love this book, so far.. I particularly love the first chapter (OK, haven't read anything else yet..), wherein Adriaan/Emilio start right off the bat by demystifying OMT. Thank you thank you thank you guys. Maybe this book will help de-ossify, de-orthopaedicalize, PT in Canada. (Maybe not.. maybe it's beyond hope.. )

Anyway, here is what Adriaan and Emilio have to say (references removed for brevity, for now): 

Quote:
There is evidence that therapists struggle when treating patients with chronic pain... Although it is likely that many factors are involved, it is believed that a significant contribution to this clinical struggle is the lack of training and preparedness for treating chronic pain.. Not only are therapists under-prepared to treat this challenging population, but the pain models they follow are outdated and the treatment options that flow out of these models are often ineffective, leading to additional frustration. Therapy, especially orthopedic therapy, is traditionally rooted in a biomedical model that focuses on tissues and tissue injury. This traditional biomedical model of therapy suggests that every disease process (dysfunction) can be explained in terms of an underlying deviation from normal function, such as a pathogen or injury. The model implies that pathology and symptoms are correlated such that a greater expression of symptoms in patients would indicate greater underlying pathology. The model proposes that correction of the underlying pathology with treatment (for example, injection, surgery, manipulation, or exercise) should result in elimination of the symptoms and subsequent restoration of normal function in the patient. Clinical experience and pain science research tells us otherwise. Many patients will demonstrate physical and diagnostic signs that they have recovered from injury, yet they will continue to report symptoms/pain. Conversely, it has been well documented that many healthy asymptomatic people and patients often have significant tissue pathology (arthritis of the spine, bulging discs, bone spurs, etc.) yet experience little to no pain.

The time has come for therapists to take on the more comprehensive biopsychosocial model (which) encompasses more than just the biological factors (anatomy, physiology, pathoanatomy) in human functioning by addressing the psychological (thoughts, emotions, behaviors) and social (work, culture, religion) factors, which are known to play a significant role in patients experiencing pain A true biopsychosocial model includes a greater understanding of how the nervous system processes injury, disease, threat and emotions.

Thank you, Adriaan and Emilio, for your refreshing bluntness. 

I will quote these 2 little paragraphs every time I bump into anyone in my own country who jumps down my throat at the mere suggestion that orthopaedic manual therapy isn't the highest and most deserving of reverence kind of PT available on the face of the planet.
(Oh yeah... it has happened. It wasn't pleasant.)

I like this excerpt from pages two and three so much that I think I might blog on it for awhile, dig up the references, even..
Just these two paragraphs.

1. Louw A, Puentedura E; Therapeutic Neuroscience Education
Orthopedic Physical Therapy Products; 1 edition (August 19, 2013)


Tuesday, May 20, 2014

SOME FINAL THOUGHTS ON NON-SPECIFIC EFFECTS

My take on why manual therapy "works", part 8.

OLDER POSTS IN THIS SERIES
Part 1: IS MANUAL THERAPY EVEN NECESSARY?  
Part 2: NEUROTAGS! YOU'RE IT!  
Part 3: ABOUT "LEARNING"  
Part 4: SKIN STRETCHING AND MOVEMENT ILLUSIONS  
Part 5:  TACTILE DIRECTION DISCRIMINATION IN THE DORSOLATERAL PREFRONTAL CORTEX 
Part 6: MORE ABOUT DORSOLATERAL PREFRONTAL CORTEX 
Part 7: TREATMENT CONTEXT, NON-SPECIFIC EFFECTS 

The last statement in the SomaSimple post is:

"Non-specific effects is the term used when the word "placebo effect" is too contentious."



That was meant to be a bit tongue-in-cheek.. but when I use this slide from Benedetti, I do cross out the word "placebo" and substitute, "Non-medical, non-surgical, non-pharmaceutical non-specific effects follow processing of  YES-ciception".
SOURCE (1)


A big piece of this is avoiding nocebo. Why? Because nocebo makes the brain produce cholecystokinin or CCK. So what, you might ask. Well, consider this: CCK antagonizes the effect of endogenous opioids and thereby reduces the effect we want, i.e., descending inhibition of a favourable kind down the spinal cord of the patient we are treating from nuclei in and around and through the periaqueductal grey or PAG, a deep deep part of the critter brain.

How does nocebo do that? It messes with rostral centres which are busy trying to gauge threat, inside a neuromatrix which has many opinions based on prior experience and learning.
We have no idea what the neurotags might be in any given patient. However, the more we can stay away from words like torn or frayed or degenerated or even tissue, when we talk to patients, the better, as Adriaan Louw pointed out in his excellent blogpost





About placebo response then, or non-specific effects if you prefer, or just learning a new idea which can change the brain over time, in an old blogpost I compared placebo to a match to be lit for anything to be able to happen in terms of eliciting descending modulation of a favourable kind, to kill that other fire that is pain. Not that a bunch of other stuff doesn't need to be there too.. fuel, a place to burn it safely, maybe someone on the outside who will help the flame come to life then stay alive long enough to do some good. Nocebo is like putting matches under the tap first. Trying to strike them while standing in the shower.
Just the idea that someone else thinks the situation isn't hopeless is usually enough to encourage hope. Hope can light the match quite well, provided the match is kept nice and dry, and provided the patient is taught about caring for their own matches.
..........


This concludes the series on "
My take on why manual therapy "works""


1.  The Placebo and Nocebo Effect: How the Therapist’s Words Act on the Patient’s Brain. Fabrizio Benedetti, writing for Karger Gazette. 

2. Every Chronic Pain Patient Has a Brain - Adriaan Louw, OPTP blog, April 2014
3. Pain and fire - HumanAntiGravitySuit blogpost,  Jan 21 2012









Thursday, May 15, 2014

TREATMENT CONTEXT, NON-SPECIFIC EFFECTS

My take on why manual therapy "works", part 7.


OLDER POSTS IN THIS SERIES
Part 1: IS MANUAL THERAPY EVEN NECESSARY?  
Part 2: NEUROTAGS! YOU'RE IT!  
Part 3: ABOUT "LEARNING"  
Part 4: SKIN STRETCHING AND MOVEMENT ILLUSIONS  
Part 5:  TACTILE DIRECTION DISCRIMINATION IN THE DORSOLATERAL PREFRONTAL CORTEX 
Part 6: MORE ABOUT DORSOLATERAL PREFRONTAL CORTEX
NEWER POSTS IN THIS SERIES
Part 8: SOME FINAL THOUGHTS ON NON-SPECIFIC EFFECTS

..............

The next statement in the SomaSimple post is: 

"7. Even if you think you have to mobilipulate people (i.e., engage in manual therapy overkill), you still have to properly set a patient's expectation, because no matter WHAT you think you're doing, it still all boils down to non-specific effects being the crucial variable."
I linked to the Bialosky paper from 2008 (1), to include all those at the far end of the manual therapy spectrum, the extremes of the operator mentality endemic in manual therapy. To their credit, these manual therapy researchers took what I like to call the "operator model" of manual therapy to its limit, analyzed the method, and, according to this paper at least, concluded that it's not the method, it's the non-specific effects that are important in pain resolution.  Effects that happen to correlate with a technical application of force into an alive awake person's body being protected by an alive awake nervous system, but still don't "prove" that the method is important, only that people will get better with manual therapy because... brain.*

Some Canadian PTs from Edmonton's University of Alberta have the right idea (according to me, at least). One is Jorge Fuentes(2), whose PhD thesis demonstrated that  "how a physiotherapist interacts with a patient verbally, through eye contact, body language and listening skills is almost as important as the treatment itself."

Another is Maxi Miciak(3) who says,

"[Jerome Frank's] (4) "..conceptual framework includes four common features: (i) an emotionally charged confiding relationship with a helper, (ii) a healing setting where there is belief the therapist can help and is acting in the client’s best interests, (iii) a rationale, conceptual scheme or myth that plausibly explains the symptoms and prescribes a procedure for resolving the symptoms, (iv) a ritual or procedure that requires active participation of both patient and therapist and is believed by both to be the means of restoring health."   
Be sure to read her blog posts on the topic, Finding Freud in Physiotherapy Part 1(5) and Part 2 (6).

I'm pretty confident these two are on the right track.
If they are, one can extrapolate that the heavy-duty-industrial-strength kinds of manual therapy can be allowed to go extinct. So can any of the professions or branches of the human primate social grooming tree that support them. Those branches can come crashing down for all I care but I hope the tree will live on. We are still primates, after all, needing physical contact for our brains to grow, then periodically thereafter. Until or unless we become fully cyborg-ed.. fully wired up to/into/chemically controlled by the society we depend on... but this isn't about that, so I'll leave that topic alone at this point.
 

*In a later paper they tried to revert to saying, "Yeah, we said non-specific in that earlier paper, but really people, we should all do high-velocity stuff, because... evidence." Whereupon Jason Silvernail and I protested in a letter to the editor(7) which was published (resulting in my one and only citation), thanks entirely to Jason Silvernail who spotted the incongruence, because he follows all that mobilipulation literature, whereas I think outcome studies, although necessary I guess, are mostly tooth fairy science, so I let my interests travel elsewhere. The letter was built around a google doc I wrote, trying to analyze what therapists do in terms of doing things "to" people as opposed to doing things "with" people, that I called Operator/Interactor models of therapy(8). Will Stewart interviewed us following its publication. (9)

.......................



1. Joel E Bialosky, Mark D Bishop, Michael E Robinson, Josh A Barabas, and Steven Z George; The influence of expectation on spinal manipulation induced hypoalgesia: An experimental study in normal subjects. BMC Musculoskeletal Disorders 2008, 9:19 (open access) 

2.  Richard Siemens;  Physiotherapy patient interaction a key ingredient to pain reduction, research says. U Alberta via Medical Xpress June5 2013

3. Miciak M1, Gross DP, Joyce A. A review of the psychotherapeutic 'common factors' model and its application in physical therapy: the need to consider general effects in physical therapy practice.  Scand J Caring Sci. 2012 Jun;26(2):394-403

4. Frank JD, Frank JB. Persuasion and Healing: A Comparative Study of Psychotherapy, 3rd edn. 1991, The Johns Hopkins University Press, Baltimore.
5. Miciak M; Visioning Practice Through a Psychotherapeutic Lens. IgnitePhysio.ca blogpost May3 2014 6. Miciak, M; Contextual Theory –An Unexpected Ally. IgnitePhysio.ca blogpost May 9 2014


7. Diane F Jacobs, PT and Jason L Silvernail, DPT, DSc, FAAOMPT; Therapist as operator or interactor? Moving beyond the technique. J Man Manip Ther. May 2011; 19(2): 120-121

8. Diane Jacobs; Operator/Interactor: Manual Therapy and its Treatment Models. Google doc 2011

9. Will Stewart; Moving Beyond the Technique: From Operator to Interactor. Podcast interview with Diane Jacobs and Jason Silvernail, 102:26 minutes, 2012.






Wednesday, May 14, 2014

MORE ABOUT DORSOLATERAL PREFRONTAL CORTEX


My take on why manual therapy "works", part 6.

OLDER POSTS IN THIS SERIES
Part 1: IS MANUAL THERAPY EVEN NECESSARY? 
Part 2: NEUROTAGS! YOU'RE IT! 
Part 3: ABOUT "LEARNING" 
Part 4: SKIN STRETCHING AND MOVEMENT ILLUSIONS 
Part 5:  TACTILE DIRECTION DISCRIMINATION IN THE DORSOLATERAL PREFRONTAL CORTEX
NEWER POSTS IN THIS SERIES

Part 7: TREATMENT CONTEXT, NON-SPECIFIC EFFECTS  
Part 8: SOME FINAL THOUGHTS ON NON-SPECIFIC EFFECTS



..................


The next statement in the SomaSimple post is: 
6. If you already have the patient's DLPFC primed with some pain ed, you'll be able to get it to focus on skin stretch/ruffini input. 
What? How can we know that?
.........

We human primate social groomers are so accustomed to thinking bottom up that we may not even know what DLPFC even is. So this post will be a very simple tutorial about that.

What is DLPFC?
It's easy enough to look up in Wikipedia, so let's go do that. (1)

"The dorsolateral prefrontal cortex (DLPFC or DL-PFC) is an area in the prefrontal cortex of the brain of humans and primates. It is one of the most recently evolved parts of the human brain, that undergoes an extremely prolonged period of maturation that lasts until adulthood.[1] DLPFC is not an anatomical structure, but rather a functional one. This region lays in the middle frontal gyrus of humans (i.e., lateral part of Brodmann's area (BA) 9 and 46 [2] and in macaque monkeys, this region is around the principal sulcus (i.e., in Walker's area 46 [3]).[4][5] Other sources consider that DLPFC is attributed anatomically to BA 9 and 46 [6] and BA 8, 9 and 10.[1]
DLPFC is connected to the orbitofrontal cortex, and to a variety of brain areas, which include the thalamus, parts of the basal ganglia (specifically, the dorsal caudate nucleus), the hippocampus, and primary and secondary association areas of neocortex, including posterior temporal, parietal, and occipital areas.[7] Also, DLPFC is the end point for the dorsal pathway (stream) that tells the brain how to interact with the stimuli. On the other hand, the ventrolateral prefrontal cortex (located more inferior/ventral to DLPFC) is the end point of the ventral pathway (stream) that brings information about the stimuli’s characteristics.[8]
An important function of the DLPFC is the executive functions, such as working memorycognitive flexibility, planning, inhibition, and abstract reasoning.[9] However, DLPFC is not exclusively responsible for the executive functions. All complex mental activity requires the additional cortical and subcortical circuits with which the DLPFC is connected.[10]The DLPFC is also the highest cortical area that is involved in motor planning, organization and regulation.[10]"

It's the bit we use for thinking. And socializing I guess. We human primates are usually very proud of this bit, even though we often have issues with whatever other peoples' dorsolateral prefrontal cortex comes up with or have come up with.

For example, using my own DLPFC, I can easily spot holes in other peoples' ideas about manual therapy. It's a lot harder for me to spot my own!

Anyway, this is the bit that Lundblad was viewing in the scanner when he examined his unique subject who had the iatrogenically wounded spinal cord on just one side in just one dorsal column pathway (see 
Part 5:  TACTILE DIRECTION DISCRIMINATION IN THE DORSOLATERAL PREFRONTAL CORTEX).
This is the bit he figured out had tactile direction discrimination. Yes, this area is not only cognitive-evaluative, it's also sensory-discriminative. With emphasis on discriminative.
(See Melzack's neuromatrix model (2)) 

SOURCE(3)
Here is a very nice picture of it. 
It's the purple area
right where horns would grow 
out of our heads (if we had horns). 



It does so very much much more however. It is so wired into other regions of the brain. Mostly it serves to inhibit. Everything else in there. When it wants to. Which is why we need to recruit it right up front so it can get busy busting up irrational ideation and dismantling unwanted detrimental neurotags for the long haul.

But we can also get it busy sensing what we are doing on the patient's skin surface. How cool is that!?

...................


2. Melzack R; Pain and the Neuromatrix in the Brain. Journal of Dental Education 2001,Volume 65, No. 12, 1378-1382 (full pdf)
3. Web Topic 8.7: Brains and Decision Making. Bradbury JW, Vehrencamp SL; Principles of Animal Communication 2nd Ed., online companion to the textbook Principles of Animal Communication, Second Edition by Jack W. Bradbury and Sandra L. Vehrencamp, published by Sinauer Associates.







Tuesday, May 13, 2014

TACTILE DIRECTION DISCRIMINATION IN THE DORSOLATERAL PREFRONTAL CORTEX



My take on why manual therapy "works", part 5.

OLDER POSTS IN THIS SERIES

Part 1: IS MANUAL THERAPY EVEN NECESSARY? 
Part 2: NEUROTAGS! YOU'RE IT! 
Part 3: ABOUT "LEARNING" 
Part 4: SKIN STRETCHING AND MOVEMENT ILLUSIONS
NEWER POSTS IN THIS SERIES
Part 6: MORE ABOUT DORSOLATERAL PREFRONTAL CORTEX 
Part 7: TREATMENT CONTEXT, NON-SPECIFIC EFFECTS 
Part 8: SOME FINAL THOUGHTS ON NON-SPECIFIC EFFECTS




..................




The next statement in the SomaSimple post is:

"This will engage the dorsolateral prefrontal cortex, even. (See Lundblad et al 2010, about Ruffinis and DLPFC)"

It's time to revisit that Lundblad paper (1). Actually, Olausson was involved in it, of course..
He seems to be involved in all papers that involve exteroceptive or interoceptive skinput.

Here is the full reference:

Lundblad LC, Olausson HW, Malmeström C, Wasling HB. Processing in prefrontal cortex underlies tactile direction discrimination: An fMRI study of a patient with a traumatic spinal cord lesion. Neurosci Lett. 2010 Oct 15;483(3):197-200

ABSTRACTWe have investigated cortical processing of tactile direction discrimination (TDD) in a patient with unilateral tactile disturbance due to spinal cord lesion. The patient R.A. (male, 45 years old), suffers from a traumatic dorsal column lesion at the level of Th XI-XII on the right side. He was instructed to report the direction of 2mm long skin pull stimulations applied in a proximal or distal direction on his right or left lower legs during functional magnetic resonance imaging (fMRI). Although R.A. considered himself to have nearly normal tactile sensibility, testing showed severely disturbed TDD on his right leg whereas results were within the range of healthy subjects on his left leg. For both legs TDD activated an extensive cortical network that included opercular parietal area 1 (OP1) of the second somatosensory cortex (S2), as has previously been observed in healthy subjects. However, dorsolateral prefrontal cortex (DLPFC) and anterior insular cortex (AIC) were only activated for the unaffected (left) leg where TDD was normal. A revisit of previously published data showed that healthy subjects consistently had TDD-related activations in DLPFC and AIC. However, in several healthy subjects AIC, but not DLPFC, was also activated for skin pull stimulations per se without the TDD task. Thus, the patient's data, in conjunction with the previous results from healthy subjects, suggest that DLPFC processing is important for tactile decision making based on proper tactile input.

The implications are kinda huge, actually... Here is my confirmation bias, full on, full blast:  I very much like the idea that Ruffinis (my very favourite sensory ending, way out in skin, easy to manipulate - dead easy) are somehow totally tied up with tactile direction discrimination! Not just sensing, but direction discrimination! Movement illusion!
This study demonstrated, in a single subject with an incredibly rare iatrogenic spinal cord lesion (that only affected his dorsal column pathway(3), and only on one side!..the control group was built right in!!).. that the dorsolateral prefrontal cortex activated on the appropriate (opposite) side, with skin stretch, inside an MRI machine, from skin stretch on the unaffected leg, but did not with skin stretch on the affected leg, whereas everything else in the brain activated bilaterally. Effectively isolating DLPFC as being divorced/severed from input from (specifically, one presumes) Ruffini input. By said lesion to the dorsal column pathway.

I mean, how often does an opportunity to combine all those factors into one study come along? The odds against this combination of factors plus a researcher canny enough to want to know, and willing to build a machine that would be acceptable to a scanner, plus a patient willing to go in one just for the research, after having his spinal cord injured by an epidural injection gone wrong in the first place for something totally unrelated - I mean.. sometimes the universe knocks me back on my butt, it's so marvelous at coughing up stuff like this every so often!  
It's pretty unlikely that something like this would ever be replicable. But that doesn't mean it isn't great science and great scientific deciphering.

OK, enough of the science appreciation. Please read the blogpost I linked to, where you'll see a picture of the device that the patient wore inside the scanner, and a description of the paper itself. And a lot more gee-whiz golly-gee science appreciation writing by me that you may ignore if you so choose.


1.  Lundblad LC, Olausson HW, Malmeström C, Wasling HB. Processing in prefrontal cortex underlies tactile direction discrimination: An fMRI study of a patient with a traumatic spinal cord lesion. Neurosci Lett. 2010 Oct 15;483(3):197-200



3. Overview of ascending pathways: Dermoneuromodulation: Ascending pathways Mar11/2012



Monday, May 12, 2014

SKIN STRETCHING AND MOVEMENT ILLUSIONS


My take on why manual therapy "works", part 4.

OLDER POSTS IN THIS SERIES


Part 1: IS MANUAL THERAPY EVEN NECESSARY?
Part 2: NEUROTAGS! YOU'RE IT! 
Part 3: ABOUT "LEARNING" 
NEWER POSTS IN THIS SERIES
Part 5: TACTILE DIRECTION DISCRIMINATION IN THE DORSOLATERAL PREFRONTAL CORTEX
Part 6: MORE ABOUT DORSOLATERAL PREFRONTAL CORTEX
Part 7: TREATMENT CONTEXT, NON-SPECIFIC EFFECTS 
Part 8: SOME FINAL THOUGHTS ON NON-SPECIFIC EFFECTS

The 4th statement from the SomaSimple post is this:
4. Add a novel stimulus, e.g., skin stretching (see Gandevia and Collins 2005)(1), allow the brain to enjoy a movement illusion. "Illusory movements were evoked at the interphalangeal (IP) joints of the index finger, the elbow, and the knee by stimulation of populations of cutaneous and muscle spindle receptors, both separately and together."

SKIN INPUT AFFECTS MOTOR OUTPUT

Simon Gandevia has been at this whole neurophysiology business for decades. I tried to read his papers a number of years ago (but got distracted by something else, as usual..)
Anyway, I remember one paper in which he had difficulty separating all those annoying cutaneous receptors away from all the juicy muscle spindle receptors he was actually trying to get at and measure. I think it had to do with reflex testing - you know, tapping the patellar tendon to get the quads to jump a bit. In this paper, it looks like he succeeded in isolating muscle spindles but at the same time, Collins and he decided to study cutaneous receptors as well - their effects on movement illusion.

It's a great little paper. In my life it represents a bit of a watershed paper in that it pointed out a really important thing - that the brain takes cues from receptors in skin (and this from a muscle spindle researcher!), not just from muscle. You see, back in the day, my training was completely lopsided - the nervous system was only important for, and was taught as, a motor output system. There was no emphasis on anything afferent, except from muscle spindles. Nervous system as black box connected only to muscles, input or output. Everything else, inconsequential.
Unless you are an aspiring human primate social groomer - then it would have been really nice to have learned something about how the brain codes for skin-put.

Anyway, back to the Collins and Gandevia paper. Not only does the brain take cues from receptors in skin, it creates movement illusions based only on the information it gets from skin! Remarkable. Sort of a ++ for simple human primate social grooming. Aha! So, if you want the brain to think there is more space around a certain place, like a knee joint maybe, stretch the skin there and see if the knee will bend further after. (It will, most of the time. Unless there is an actual mesodermal blockage in there, and not just a critter brain, interoceptive pain illusion that feels like a restriction.)

Gandevia and Proske published another paper (2) a few years ago about kinesthesia.
Turns out Ruffini endings contribute to proprioception. What do you know? In fact they say skin receptors are more likely to play a role in joint position sense than joint receptors do. Oh, they still love their muscle spindles, of course, but look: 

"The cutaneous receptor most likely to subserve a kinaesthetic role is the skin stretch receptor, the slowly adapting Type II receptor served by Ruffini endings (Chambers et al.1972Edin, 1992). For kinaesthesia at the forearm, stretch of skin over the elbow during elbow flexion can provide information about both position and movement. Movement illusions generated by stretch of skin of the hand and over more proximal joints, when combined with muscle vibration were greater than when either stimulus was applied on its own (Collins et al. 2005). The authors made the point that this was not just a matter of skin input facilitating the muscle input and that cutaneous input generated by skin stretch contributed to kinaesthesia in its own right."
Now, add this together with what Olausson and his colleagues have been doing in Sweden for decades(3), and I think we have a case for skin-put having an important role in the world. Not that we're going to ever stop doing it - human primate social groomers are just doing what our own vertebrate mammal primate nervous systems have always done, since whenever they started self-organizing then interacting half a billion years ago. 


YES-CICEPTIVE INPUT

I have already blogged my fingers to the bone about Olausson and his group in Sweden. Read all about it.






  • THE FINE OLD ART OF FINGER PULLING







  • Don't be confused about this video - a lot of emphasis has been placed on the visual component of the illusion. I would argue that the kinesthetic component is equally if not more important. It wouldn't be very hard for some clever researcher type to design a test for that - blindfold one group of participants, pull their fingers in exactly the same way, in the machine. Have another group just look, don't touch them at all. Use the mirrors to make it look like their fingers lengthen all by themselves. A third group could have both illusions at the same time. 

    I bet the last group would have the best results, but hey, if the first group had pretty good results, you wouldn't need a great big expensive machine to create a movement illusion, and ordinary human primate social grooming would be vindicated.

    1. Collins D, Refshauge KM, Todd G, Gandevia SC; Cutaneous receptors contribute to kinesthesia at the index finger, elbow, and knee. J Neurophysiol. 2005 Sep;94(3): 1699-706 (full text pdf)

    2. Proske U, Gandevia SC; The kinaesthetic sensesThe Journal of Physiology, 587, 4139-4146. (full text)

    3. Mind tricks may help arthritic pain

    4. Illusion could halve the pain of osteoarthritis, scientists say