title: Changes of the Sensory Abnormalities and Cortical Excitability in Patients with Complex Regional Pain Syndrome of the Upper Extremity After 6 Months of Multimodal Treatment.
abstract: The most prominent sensory sign of the complex regional pain syndrome (CRPS) is blunt hyperalgesia, but longitudinal studies on its relation to the outcome of long-term multimodal treatment are lacking.
  
  
  
  We examined 24 patients with CRPS type I using standardized Quantitative Sensory Testing on the affected hand and the contralateral hand at baseline and 6 months following treatment. Somatosensory evoked potentials after single and paired-pulse stimulation of the median nerve were performed to assess the paired-pulse suppression (n = 19). Treatment response at follow-up was defined as pain relief > 30% and improved hand function. Statistics: Wilcoxon test, Pearson correlation.
  
  
  
  At baseline, similar to previous studies, the pressure pain threshold (PPT) was significantly decreased and the pain response to repeated pinprick stimuli was significantly increased, while all detection thresholds were within the normal range without any difference between the later treatment responders and non-responders. After 6 months of treatment, the PPT increased significantly in the whole study group. However, the pressure hyperalgesia improved only in treatment responders (n = 17, P  < 0.05), whereas there was no improvement in non-responders (n = 7). The rest of the sensory profile remained nearly unchanged. There was a correlation between the paired-pulse suppression and the PPT only at follow-up (r = 0.49, P  < 0.05), but not at baseline, where low pressure pain threshold was associated with impaired paired-pulse suppression.
  
  
  
  Thus, the persistence of blunt hyperalgesia seems to be associated with impaired paired-pulse suppression, both representing maladaptive central nervous changes in CRPS, which may account for the treatment non-response in this subgroup.
authors.affiliation: Departments of Neurology, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Bochum, Germany.
authors.forename: Elena K
authors.initials: EK
authors.lastname: Enax-Krumova
authors.affiliation: Departments of Neurology, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Bochum, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Lenz
authors.affiliation: Departments of Neurology, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Bochum, Germany.
authors.forename: Jule
authors.initials: J
authors.lastname: Frettlöh
authors.affiliation: Departments of Neurology, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Bochum, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Höffken
authors.affiliation: Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Reinersmann
authors.affiliation: Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schwarzer
authors.affiliation: Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Westermann
authors.affiliation: Departments of Neurology, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Bochum, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Tegenthoff
authors.affiliation: Pain Medicine, BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Maier
mesh_terms: D000328:Adult; D000368:Aged; D003131:Combined Modality Therapy; D020918:Complex Regional Pain Syndromes / Q000503:physiopathology* / Q000628:therapy; D000071080:Cortical Excitability / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold; D034941:Upper Extremity / Q000503:physiopathology
keywords: Complex Regional Pain Syndrome; Cortical Disinhibition; Pressure Hyperalgesia; Sensory Abnormalities; Treatment Effects