title: Neural markers of neuropathic pain associated with maladaptive plasticity in spinal cord injury.
abstract: OBJECTIVE
  Given the potential use of neural markers for the development of novel treatments in spinal cord pain, we aimed to characterize the most effective neural markers of neuropathic pain following spinal cord injury (SCI).
  
  
  METHODS
  A systematic PubMed review was conducted, compiling studies that were published prior to April, 2014 that examined neural markers associated with neuropathic pain after SCI using electrophysiological and neuroimaging techniques.
  
  
  RESULTS
  We identified 6 studies: Four using electroencephalogram (EEG); 1 using magnetic resonance imaging (MRI) and FDG-PET (positron emission tomography); and 1 using MR spectroscopy. The EEG recordings suggested a reduction in alpha EEG peak frequency activity in the frontal regions of SCI patients with neuropathic pain. The MRI scans showed volume loss, primarily in the gray matter of the left dorsolateral prefrontal cortex, and by FDG-PET, hypometabolism in the medial prefrontal cortex was observed in SCI patients with neuropathic pain compared with healthy subjects. In the MR spectroscopy findings, the presence of pain was associated with changes in the prefrontal cortex and anterior cingulate cortex.
  
  
  CONCLUSIONS
  When analyzed together, the results of these studies seem to point out to a common marker of pain in SCI characterized by decreased cortical activity in frontal areas and possibly increased subcortical activity. These results may contribute to planning further mechanistic studies as to better understand the mechanisms by which neuropathic pain is modulated in patients with SCI as well as clinical studies investigating best responders of treatment.
authors.affiliation: School of Technology and Management and Centre for Rapid and Sustainable Product Development, Polytechnic Institute of Leiria, Leiria, Portugal; Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School, Charlestown, MA, U.S.A.
authors.forename: Paula
authors.initials: P
authors.lastname: Pascoal-Faria
authors.forename: Nilufer
authors.initials: N
authors.lastname: Yalcin
authors.forename: Felipe
authors.initials: F
authors.lastname: Fregni
mesh_terms: D015415:Biomarkers; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009437:Neuralgia / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D009473:Neuronal Plasticity; D010147:Pain Measurement / Q000379:methods; D013119:Spinal Cord Injuries / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy
chemical_list: D015415:Biomarkers
keywords: neural markers; neuropathic pain; neuroplasticity; pain; spinal cord injury