Neurophysiological Basis of Rehabilitation in Complex Regional Pain Syndrome, Type I and Chronic Low Back Pain
Condition: Chronic Pain
MeSH terms: Complex Regional Pain Syndromes; Reflex Sympathetic Dystrophy; Back Pain; Low Back Pain; Chronic Pain
Study type: Observational

Summary: 
      Complex Regional Pain syndrome Type I (CRPS-I) is a chronic progressive disease. Patients
      experience dramatic decline of overall well-being, despite the absence of any apparent
      physical cause. The main symptoms are hypersensitivity to pain (hyperalgesia) and
      experiencing normal tactile stimulation as painful (allodynia) in the absence of peripheral
      nerve damage. The debate on the aetiology of CRPS-I is still open.

      The therapy offered to CRPS-I patients is diverse and can involve invasive and non-invasive
      interventions. Current (inter)national guidelines recommend physiotherapy as the best
      non-invasive treatment for rehabilitation. Recently, cognitive and behavioural Graded
      Exposure in Vivo (GEXP) therapy aimed at reducing pain-related fear was found to be effective
      (De Jong et al. 2005), and more effective than standard physical therapy (ReMOVE study,
      articles in preparation). By reducing pain-related fear EXP might reconcile motor output and
      sensory feedback.

      Another type of pain is lower back pain (LBP), which affects 70% to 85% of general
      population, but usually heals within 12 weeks in 90% of patients. The rest of the patients
      suffer from intractable, chronic LBP despite no evident organic abnormality. Research shows
      that also in these patients cognitive and behavioural aspects of pain are important and
      related to physical performance and self-reported disability (Vlaeyen et al., 2000). Several
      studies have demonstrated the success of GEXP in this patient group: GEXP resulted in
      improvements in pain-related fear, catastrophizing, performance of daily relevant activities,
      and in pain intensity (Leeuw et al., 2008).

      This study aims to investigate the effect of GEXP on brain regions involved in the processing
      of harmless tactile stimuli in CRPS-I and CLBP patients, as well as its effect on tactile
      discrimination thresholds. We hypothesize that GEXP will induce 1) an improvement of tactile
      discrimination thresholds, 2) a functional reorganization of primary and secondary
      somatosensory cortex (in regions related to the affected limb in CRPS-I; and to the back in
      LBP), 3) changes in activation of emotional brain circuits during non-noxious stimulation, 4)
      changes in resting state connectivity between emotional and sensory brain areas, 5) changes
      in measures reflecting white matter integrity. No systematic changes are expected in the
      healthy controls.

      Patients diagnosed with CRPS-I and CLBP will participate in a Magnetic Resonance Imaging
      (MRI) experiment. In this observational study, we examine the effects of GEXP treatment that
      all patients receive as part of usual care. Anatomical as well as diffusion-weighted and
      T2*-weighted (Blood oxygenation level dependent) MR images will be acquired. The study has a
      3x4 split plot design with group (CRPS-I patients and CLBP receiving GEXP treatment / healthy
      controls) as between-subjects variable and time (pre-, during, post-treatment and follow-up)
      as within-subject variable.
    


Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        People diagnosed with CRPS, type I, and people with chronic low back pain (CLBP) are target
        population for this study. A group of healthy controls matched for age, gender and
        handedness will also take part in the study.