title: Complex regional pain syndrome is associated with structural abnormalities in pain-related regions of the human brain.
abstract: Complex regional pain syndrome (CRPS) is a chronic condition that involves significant hyperalgesia of the affected limb, typically accompanied by localized autonomic abnormalities and frequently by motor dysfunction. Although central brain systems are thought to play a role in the development and maintenance of CRPS, these systems have not been well characterized. In this study, we used structural magnetic resonance imaging to characterize differences in gray matter volume between patients with right upper extremity CRPS and matched controls. Analyses were carried out using a whole brain voxel-based morphometry approach. The CRPS group showed decreased gray matter volume in several pain-affect regions, including the dorsal insula, left orbitofrontal cortex, and several aspects of the cingulate cortex. Greater gray matter volume in CRPS patients was seen in the bilateral dorsal putamen and right hypothalamus. Correlation analyses with self-reported pain were then performed on the CRPS group. Pain duration was associated with decreased gray matter in the left dorsolateral prefrontal cortex. Pain intensity was positively correlated with volume in the left posterior hippocampus and left amygdala, and negatively correlated with the bilateral dorsolateral prefrontal cortex. Our findings demonstrate that CRPS is associated with abnormal brain system morphology, particularly pain-related sensory, affect, motor, and autonomic systems.
  
  
  CONCLUSIONS
  This paper presents structural changes in the brains of patients with CRPS, helping us differentiate CRPS from other chronic pain syndromes and furthering our understanding of this challenging disease.
authors.affiliation: Stanford University School of Medicine, Stanford University, Palo Alto, California.
authors.forename: Meredith J
authors.initials: MJ
authors.lastname: Barad
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Ueno
authors.affiliation: Stanford University School of Medicine, Stanford University, Palo Alto, California.
authors.forename: Jarred
authors.initials: J
authors.lastname: Younger
authors.affiliation: Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Neil
authors.initials: N
authors.lastname: Chatterjee
authors.affiliation: Stanford University School of Medicine, Stanford University, Palo Alto, California. Electronic address: smackey@pain.stanford.edu.
authors.forename: Sean
authors.initials: S
authors.lastname: Mackey
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D015331:Cohort Studies; D020918:Complex Regional Pain Syndromes / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000473:pathology; D009929:Organ Size; D010147:Pain Measurement; D012720:Severity of Illness Index; D013997:Time Factors; D034941:Upper Extremity; D055815:Young Adult
keywords: Voxel-based morphometry; chronic pain; complex regional pain syndrome; neuroimaging