Final Report: 2009 Rachel Tobias Young Investigator Award Project
By Jenny Lewis, PhD, MSc, Dip COT

Relationship between body perception disturbances and cortical representation of the affected upper limb in CRPS

Poster: Inflated Limbs, A perception or reality? Impaired tactile acuity and disparities between actual and perceived size of the affected limb in complex regional pain syndrome (CRPS)

Data collection
I returned to Montreal from the UK in August 2010 to present at the International Association of Study of Pain (IASP) World Congress and whilst there took the opportunity to collect further scanning and clinical data on four new participants. Forty eight participants have undertaken the study, 22 of whom have CRPS of one upper limb.

Analysis of data
Psychophysical data from this research has been analysed. The following abstract summarises these findings.

The aim of this study was to explore the relationships between alterations in body perception, pain, tactile acuity and swelling. A controlled observational design was used to measure these features amongst those with CRPS of one arm.

The extent of body perception disturbance was captured using the Bath CRPS body perception disturbance scale and the Neuropathic Pain Symptom Inventory measured pain. Hand swelling was determined via the volume of water displaced from a volumeter. Two point discrimination threshold testing was performed as a measure of tactile acuity.

Those with longer disease duration had significantly greater body perception disturbance (r=0.66 p=0.001). Similarly, a significant relationship between body perception disturbance and pain was found such that those in greater pain had more extensive body perception disturbance (r=0.56 p=0.006). Findings revealed a significant correlation between body perception disturbance and tactile acuity in that those with worse body perception disturbance had poorer tactile discrimination (r=0.5 p=0.024). A tri-modal relationship between pain, body perception disturbance and tactile acuity is suggestive of aberrant central processing. The exact relationship between these factors requires further exploration

Analysis of the brain imaging data from this research is ongoing and will be completed by the end of this year.

Dissemination of research
I presented the psychophysical data at the IASP World Congress in August. This was presented orally at the SIG CRPS symposium Where we are today and via a poster presentation both of which were very well received. I have attached the poster as part of this report for your information.

A manuscript entitled Body conscious in pain: The relationship between body perception disturbance, tactile discrimination and pain in complex regional pain syndrome about the psychophysical data and including the data that has recently been collected is being submitted to PAIN.

Future plans
The considerable expertise that I have gained from working with Petra Schweinhardt particularly in relation to functional MRI (fMRI) study design and analysis has provided the knowledge to set up and undertake fMRI experimental studies here in the UK. I have established links with the brain imaging research centre at Cardiff University (CUBRIC), experts in functional imaging and will be recruiting CRPS patients from our treatment centre in Bath.

Building on the foundations of the research undertaken at McGill University that was only made possible through the Rachel Tobias Young Investigators Award, I am applying for a highly competitive UK Department of Health post-doctoral fellowship (submission deadline January 2011).

This fellowship will investigate tactile processing performance and body perception disturbance of those with CRPS and other chronic pain conditions. Functional imaging techniques will be used to determine the cortical correlates of this relationship and neural changes that may occur between baseline and follow-up of a treatment intervention study.

Added October 21, 2010