Pain Reduction by Inducing Sensory-Motor Adaptation: CRPS PRISMA trial protocol

Aims. People with CRPS can show changes in their perception of and attention to the affected limb and its surrounding space that suggest possible neuropsychological components to the disorder. These include discrepancies between sensory and motor representations of the body and space. Here we present a protocol for a clinical trial evaluating the efficacy of a sensory-motor training technique called prism adaptation (PA) previously shown to alleviate CRPS symptoms in small exploratory studies. It will further examine how neuropsychological changes relate to clinical manifestations of CRPS.

Methods. This double-blind, randomised controlled trial will enroll 42 upper-limb CRPS-I patients to undergo 2 weeks of twice-daily real or sham PA. Primary outcome measures are pain intensity and CRPS severity. Secondary measures include self-report questionnaires, clinical assessments; and psychophysical and computer-based tests of physical and neuropsychological symptoms. Data are collected at 4 and 0 weeks pre-treatment; and at 0, 4, 12 and 24 weeks post-treatment. Ethical approval was granted by the Oxford A REC (12/sc/0667).

Results. We predict greater reduction in pain and CRPS severity, and other clinical and neuropsychological signs, after real PA compared to sham treatment. We further expect more pronounced alterations in the perception of and attention to the affected limb to be associated with more severe physical symptoms of CRPS at baseline.

Conclusions. This study will provide a robust evaluation of the therapeutic effects of PA, determining its potential for CRPS rehabilitation. Furthermore, these findings will provide insights into the role of neuropsychological changes in CRPS.