The current state of cognitive neuroscience research into phantom limb pain is mixed. Although a number of viable theories have been proposed, and each is supported by research evidence, none offer a comprehensive account that can address the full range of experiences. In addition, the most prominent area of contemporary research, that into cortical reorganisation, despite its advances has failed to discover how reorganisation may cause the perceptual experience of PLP.
A discussion of Mirror therapy was included in this review in an attempt to elucidate which of the many proposed mechanisms could account for the experience of PLP. However, rather than implicating a single theory in the therapeutic benefits it offers, it is clear that any one of a number of theories could be responsible. This offers some indication that the theories may be more alike than dissimilar. Perhaps the most significant criticism of the current state of research in this area, is that each stream appears to progress independently of one another, without attempting to comprehensively integrate findings from the other areas. Figure 5. offers a tentative representation by the author of this paper as to how each of the areas discussed in this review can be integrated.
Figure 5. A tentative representation of how the various areas of research in PLP are interrelated.
Melzack’s Neuromatrix theory has been censured because its propositions are too broad to test empirically (Giummarra, et. al., 2007). However, the theoretical framework supplied by Melzack is consistent with many of the areas of current research and may provide a template through which to integrate them. In addition, although this paper has focused on central mechanisms involved in the experience of phantom limb pain, the role of peripheral factors is also important (Montoya, et al., 1997; Subedi & Grossberg, 2011). Future work should seek to incorporate each stream of research into a broad and integrated theory of PLP that may resolve the shortcomings of each individual area and allow for a more comprehensive account of individuals perceptual experience of phantom limb pain.
Phantom Limb Pain 