OUP user menu

Phantom limb pain, cortical reorganization and the therapeutic effect of mental imagery

(CC)
K. MacIver, D. M. Lloyd, S. Kelly, N. Roberts, T. Nurmikko
DOI: http://dx.doi.org/10.1093/brain/awn124 2181-2191 First published online: 20 June 2008

Summary

Using functional MRI (fMRI) we investigated 13 upper limb amputees with phantom limb pain (PLP) during hand and lip movement, before and after intensive 6-week training in mental imagery. Prior to training, activation elicited during lip purse showed evidence of cortical reorganization of motor (M1) and somatosensory (S1) cortices, expanding from lip area to hand area, which correlated with pain scores. In addition, during imagined movement of the phantom hand, and executed movement of the intact hand, group maps demonstrated activation not only in bilateral M1 and S1 hand area, but also lip area, showing a two-way process of reorganization. In healthy participants, activation during lip purse and imagined and executed movement of the non-dominant hand was confined to the respective cortical representation areas only. Following training, patients reported a significant reduction in intensity and unpleasantness of constant pain and exacerbations, with a corresponding elimination of cortical reorganization. Post hoc analyses showed that intensity of constant pain, but not exacerbations, correlated with reduction in cortical reorganization. The results of this study add to our current understanding of the pathophysiology of PLP, underlining the reversibility of neuroplastic changes in this patient population while offering a novel, simple method of pain relief.

  • functional magnetic resonance imaging
  • phantom limb pain
  • mental imagery
  • cortical reorganization
  • Abbreviations:
    Abbreviations:
    PLP
    phantom limb pain
    NRS
    Numerical rating scale
    BOLD
    blood oxygenation level-dependent
    ACC
    anterior cingulate cortex
    SMA
    supplementary motor area

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

View Full Text