On chronic pain and body schema

Pain: The Science and Culture of Why We Hurt

by Marni Jackson

"Why do we still distinguish between mental pain and physical pain," she asks, "when pain is always an emotional experience? Why is pain so poorly understood, especially in a century of self-scrutiny? Hasn't anyone noticed the embarrassing fact that science is about to clone a human being but still can't cure the pain of a bad back?"

A new take on the Gate Control Theory, or, The benefits of rubbing your boo-boos

from the blog of Dave Walton, physiotherapist and Assistant Professor with the School of Physical Therapy at University of Western Ontario.

" ... (I)t is conceivable that the brain's sentry body-self neuromatrix maintains that heightened state of arousal and sensitivity in it's efforts to obtain knowledge about the state of the painful part. This might also be the mechanism behind Peter O'Sullivan's observations that some people with chronic low back pain exhibit behaviours that result in further pain (ie. it's painful to extend the lumbar spine, but some people habitually adopt this posture despite the pain). In that case, this theory would suggest that any stimuli coming from the area, even if unpleasant, can offer at least some form of relief to a neuromatrix seeking information, especially in those conditions that you can't see. Not saying this is good, just saying it makes sense in light of my pseudo-theory. Note that this theory would also support the notion that manual therapies probably have much of their effect through drawing attention to, and providing neurophysiological stimulus from, painful parts of the body. The focus on identifying very specific movement impairments (ie. restricted superior glides of the facet) becomes less of a priority than does identifying the amount of stimulus that can be applied to a body in pain that provides adequate stimuli without being perceived as threatening to the sensitized 'pain' system."

I can't find it! Distorted body image and tactile dysfunction in patients with chronic back pain

By G. Lorimer Moseley

ABSTRACT: The conscious sense of our body, or body image, is often taken for granted, but it is disrupted in many clinical states including complex regional pain syndrome and phantom limb pain. Is the same true for chronic back pain? Body image was assessed, via participant drawings, in six patients with chronic back pain and ten healthy controls. Tactile threshold and two-point discrimination threshold (TPD) were assessed in detail. All the patients, and none of the controls, showed disrupted body image of the back. Five patients were unable to clearly delineate the outline of their trunk and stated that they could not “find it”. TPD was greatly increased in the same zone as the absence or disruption of body image, but was otherwise similar to controls. The disturbance of body image and decrease in tactile acuity coincided with the normal distribution of pain, although there was no allodynia and there was no relationship between resting pain level and TPD. Tactile threshold was unremarkable for patients and controls. These preliminary data indicate that body image is disrupted, and tactile acuity is decreased, in the area of usual pain, in patients with chronic back pain. This finding raises the possibility that training body image or tactile acuity may help patients in chronic spinal pain, as it has been shown to do in patients with complex regional pain syndrome or phantom limb pain.

Making Sense of Sense - The roads less travelled – four paths to get from touch to the body

By Nadia Barnsley, a third year medical students from the University of New South Wales.

Nadia's research interests include bodily awareness, body ownership and immune responses. She is doing an independent learning project on Body in Mind research. Here she reviews Serino and Haggard’s paper “Touch and the Body” which was published in Neuroscience and Biobehavioural Reviews.

Serino and Haggard’s paper gives a four-part model that explains the notion that our sense of touch carries information about both the external object touching our skin and also our own body. Tactile information can influence (or be influenced by) our mental representation of the physical body. Mental body representations (MBR) are simply descriptions in our mind of the parts of the body, their position in space and their organization into a structural whole (us!)

Serino and Haggard firstly examined the idea that the physical body structures tactile sensation – that when we touch or get touched, tactile afferents will map this into a homunculus, “little man”, in the parietal lobe of the brain. This information is conveyed to what’s known as S1 (the primary somatosensory cortex) of the opposite hemisphere.

Serino and Haggard’s second pathway explains that tactile information provides an important afferent input to mental body representations. Importantly they clarified the difference between body schema and body image; where body schema is short-lived and represents the positions of body parts in space, whereas body image remains fixed over time, representing a basic appearance of the body as an object in third person perspective.

Interestingly they reviewed how visual information relates to tactile sensation; the third pathway. They found that tactile acuity improved when subjects viewed the body. Moreover, this is independent from visuo-spatial orienting to the location of the body. The paper explained those with poor tactile ability will have vast improvements in tactile sensation when visual information is added. This has clinical implications for those with reduced sensation following brain lesions.

The last pathway explained how MBRs not only contribute to our body perception, but the perception of external objects. Basically, our touch of external objects is ‘body referenced’. This implies that MBRs are not just a stored body image; they are updated to integrate current sensory information.

So the first pathway tells the brain where we are being touched, the second pathway gives our brain a representation of what we are (our body image), the third is that this representation influences how we understand our sense of touch and the last being that our body image alters how external objects are perceived.

Reference: Serino A, & Haggard P (2010). Touch and the body. Neuroscience and biobehavioral reviews, 34 (2), 224-36 PMID: 19376156 Epub 2009 Apr 17.

Touch and the body
Serino A, Haggard P. Dipartimento di Psicologia and Centro studi e ricerche in Neuroscienze Cognitive, Università degli Studi di Bologna, Italy.

Abstract
The dual nature of touch has long been understood. The sense of touch seems to carry information at the same time about the external object touching our skin, and also about our body itself. However, how these two interact has remained obscure. We present an analytic model of how tactile information interacts with mental body representations in the brain. Four such interactions are described: the link between the body surface and the maps in primary somatosensory cortex, the contribution of somatosensory cortical information to mental body representations, the feedback pathway from such higher representations back to primary tactile processing in somatosensory cortex, and the modulation of tactile object perception by mental body representations.

Source: Body in Mind Research into the role of the brain and mind in chronic pain disorders

Massage and Embodiment

Article by Keith Eric Grant, PhD, NCTMB in Massage Today June, 2006, Vol. 06, Issue 06

Grant reflects on touch and the two best known paradigms of massage in the U.S. context namely massage for relaxation and massage as health care. (Despite legislation in South Africa attempting to bring all types of massage under the same umbrella, the same distinction exists here - EK)

He then discusses a third paradigm of massage that has an impact on the quality of body-sense or embodiment of the person, an approach that has been largely ignored "by those looking at massage as tissue-specific health care".

According to Grant, practising massage as sensory re-framing has no lack for material to draw from. He points to the work of:

• Maurice Merleau-Ponty who sets out a philosophical framework more than a half century ago
  

• Deane Juhan, best known as the author of Job's Body: A Handbook for Bodywork and

• Donald Bakal who lays the same stress on developing body awareness as a path to healing in his book Minding the Body: Clinical Uses of Somatic Awareness.

Read the full article at: http://www.massagetoday.com/mpacms/mt/article.php?id=13431

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