Novel Signs and Their Clinical Utility in Diagnosing Complex Regional Pain Syndrome (CRPS)

Abstract

Novel signs are reliable, easy to perform, and present in chronic pain patients. FP and BS have significant clinical utility in predicting persistent pain in a fracture group thereby allowing targeted early intervention.

Altered neurocognitive processing of tactile stimuli in patients with Complex Regional Pain Syndrome (CRPS)

“…Secondarily, consistent with previous reports 3, 4 , there was evidence of less accurate digit discrimination and longer response times in CRPS patients compared to controls, but a high degree of between-subject variability indicating heterogeneity in the mechanisms driving these performance indices. Interestingly, response times appear to provide a more robust behavioural marker of perceptual decision-making deficits in CRPS patients than measures of digit discrimination accuracy: Not only was the response time difference between groups a stronger effect, but it was also more evenly distributed across patients and more sensitive to stimulation on the affected vs. the unaffected side of the body.…”

“…Prior to testing our main hypothesis regarding cognitive cortical processing in CRPS, we sought to replicate and extend the results of previous work 3,4 that found reductions in accuracy and increases in response time in similar digit discrimination tasks in CRPS patients.…”

“…http://dx.doi.org/10.1101/146613 doi: bioRxiv preprint first posted online Jun. 7, 2017; example, previous reports found no difference in the prevalence of abnormal digit perceptions between upper and lower-limb affected CRPS patients 4 . Another example of heterogeneity is disease duration (which in the current study ranged from 1 year to 14 years); to date, there has been no systematic investigation of abnormal tactile perception of cortical processing in relation to this factor.…”

“…Of these patients, five had left arm, three had right arm and five had left leg affected respectively. The mean disease duration was 5.3 years (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

“…For example, in one such test requiring patients to identify the digit touched without corresponding visual information, just less than half of CRPS patients perform poorly on the affected hand 3 . Despite this variable performance across patients, such metrics (which include lower accuracy in discrimination but also longer response times) improve classification of CRPS patients from patients with limb fracture, even if the patients suffer from lower-limb CRPS and are tested on their hands 4 . This lack of spatial specificity suggests central mechanisms may influence performance decrements and supports further investigation of such mechanisms.…”