Excuse me, have you seen my foot?

I am glad to be able to post the following new CRPS article, published in the journal Pain.

There is a bizarre phenomenon that can occur -- no surprise with such a funky disease, but still, I know I am loathe to talk about it. To do so makes a person sound completely nuts.

Sometimes I cannot help it, though, and have been known to cry out:

WHERE IS MY LEG?

It is often one of the first questions I ask of people I meet who have CRPS -- Do you ever lose your involved limbs in space? And lose them in space despite the fact that they are delivering enormous amounts of pain? Do you have to stop and look at your legs in order to have the confidence to try another step?

Of recent evolution in my Rhetorical Question Package is this:

WHERE THE HELL IS MY HAND?

Of course, like other aspects of CRPS, you can turn these little weirdnesses into cheap home entertainment. We haven't had to go to the movies or see a play or any of those boring activities -- for years! Not when you can prop my legs up on soft pillows, covered in that oft-mentioned high-density muscovite cotton weave, and watch them turn red, purple, white, and deep blue. Once spasticity sets in -- don't despair, it might take you a few years -- the color kaleidoscope gains a diverting twisting action that you will want to rate as you might the vault of an elite gymnast.

It's also fun to play "Guess how cold?" but for that you'll need one of those sticky skin thermometers.

And popcorn! Don't forget the popcorn!

PAIN: Journal of the International Association for the Study of Pain
Volume 149, Issue 3, Pages 463-469 (June 2010)
Authors/Researchers: Jennifer S. Lewis, Paula Kersten, Kathryn M. McPherson, Gordon J. Taylor, Nigel Harris, Candida S. McCabe, David R. Blake

Wherever is my arm? Impaired upper limb position accuracy in Complex Regional Pain Syndrome

ABSTRACT:

Knowledge of the position of one’s limbs is an essential component of daily function and relies on complex interactions of sensorimotor body schema-related information. Those with Complex Regional Pain Syndrome (CRPS) express difficulty in knowing where their affected limb is positioned. The aim of this study was to determine the degree to which experimental data supported the reported difficulty in limb position sense. A controlled experimental design was used to measure upper limb position accuracy amongst those with CRPS of one arm. Position accuracy was individually measured in both arms and compared to a known target position. Video captured each of 36 trials (half with arm in full view and half with vision obscured). The error in degrees between actual and known targets was determined using video analysis software. The Brief Pain Inventory measured pain. A subjective mental image representation of both upper limbs was documented. The CRPS group had moderate pain intensity and were significantly less accurate in positioning both the affected and unaffected limbs compared to controls (p less than 0.001).

You can access the entire article in .pdf here.

INTRODUCTION

‘‘If the pain is very intense, even if I am touching something else I’ve
got no idea where my arm exists” [27, p. 115]. This description typifies
the difficulty that those with CRPS express in knowing where
their affected limb is positioned [27]. Knowledge of the position of
one’s limbs plays an essential role within the motor system – enabling
accurate and smooth movements to be performed [13]
and is a necessary component of daily functioning [18]. This sense
involves a complex interaction of proprioceptive, vestibular,
somatosensory and visual inputs from the periphery that interrelate
with motor systems [13,19,22]. Interpretation of this multisensory
information within the context of a centrally maintained
representation of the limb or ‘body schema’ provides our fundamental
sense of limb position [21,22].

However, subjective perceptual disturbances of the affected
limb are suggestive of distortions in body schema amongst those
with CRPS. Features such as a desire to amputate [8,10,27], perceptual
distortions in size and shape [27,31,32], lack of self-ownership
[12,14,27] and hostile feelings [27] have all been expressed by
individuals about their affected limb. Cortical reorganisation in regions
associated with the body schema (i.e. primary somatosensory
cortex, posterior parietal lobe) have been revealed by brain
imaging, providing further evidence of body schema disruption
[28–30,34].

Given that limb position sense is integral to performing movements
it is important to note that motor dysfunction is well recognised
in CRPS [4,14,15,23,25,37,44–47]. Brain-imaging evidence of
altered neural activity in motor cortices has also been found [30].
Despite acknowledged changes in body perception and motor
function little is known about limb position sense and performance
in CRPS. As such the aim of this study was to determine the degree
to which objective experimental data supports the ‘sense’ or reported
perception of limb-positioning difficulty. We hypothesised
that there was a statistically significant difference in affected upper
limb position accuracy in those with CRPS when compared to
healthy volunteers. In addition, we wished to determine whether
there was a relationship between limb position accuracy and
self-perception of the affected limb. Given that vision of the limb
plays an important role in updating the body schema [9,11] we
aimed to establish the extent to which vision may contribute to
limb-positioning accuracy. By addressing these aspects we set
out to provide insights into the mechanisms of limb position performance
in CRPS and how this knowledge might inform clinical
practice.