title: Gray matter changes related to medication overuse in patients with chronic migraine.
abstract: OBJECTIVE
  The objective of this article is to investigate the neurological substrates associated with medication overuse (MO) in patients with chronic migraine (CM).
  
  
  METHODS
  We recruited age- and sex-matched CM patients with MO (CMwMO), CM patients without MO (CMwoMO), and healthy controls (HCs). Magnetic resonance T1-weighted images were processed by voxel-based morphometry, and the findings were correlated with clinical variables and treatment responses.
  
  
  RESULTS
  A total of 66 patients with CM (half with MO) and 33 HCs completed the study. Patients with CMwMO compared to the patients with CMwoMO showed gray matter volume (GMV) decrease in the orbitofrontal cortex and left middle occipital gyrus as well as GMV increase in the left temporal pole/parahippocampus. The GMV changes explained 31.1% variance of the analgesics use frequency. The patients who responded to treatment had greater GMV in the orbitofrontal cortex (p = 0.028). Patients with CM (with and without MO), compared with HCs, had decreased GMV at multiple brain areas including the frontal, temporal and occipital lobes, precuneus and cerebellum.
  
  
  CONCLUSIONS
  Our study showed GMV changes in CMwMO patients compared to the CMwoMO patients. These three cerebral regions accounted for significant variance in analgesics use frequency. Moreover, the GMV of the orbitofrontal cortex was predictive of the response to MO treatments.
authors: Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taiwan.|Institute of Neuroscience, National Yang-Ming University, Taiwan.|Department of Neurology, National Yang-Ming University, School of Medicine, Taiwan.|Section of Neurology, Department of Internal Medicine, Far Eastern Memorial Hospital, Taiwan.
authors: Tzu-Hsien
authors: TH
authors: Lai
authors: Brain Research Center, National Yang-Ming University, Taiwan.
authors: Kung-Hsien
authors: KH
authors: Chou
authors: Department of Neurology, National Yang-Ming University, School of Medicine, Taiwan.|Department of Neurology, Neurological Institute, Taipei-Veterans General Hospital, Taiwan.
authors: Jong-Ling
authors: JL
authors: Fuh
authors: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taiwan.
authors: Pei-Lin
authors: PL
authors: Lee
authors: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taiwan.
authors: Yi-Chia
authors: YC
authors: Kung
authors: Institute of Neuroscience, National Yang-Ming University, Taiwan.|Brain Research Center, National Yang-Ming University, Taiwan.
authors: Ching-Po
authors: CP
authors: Lin
authors: Department of Neurology, National Yang-Ming University, School of Medicine, Taiwan sjwang@vghtpe.gov.tw.|Brain Research Center, National Yang-Ming University, Taiwan.|Department of Neurology, Neurological Institute, Taipei-Veterans General Hospital, Taiwan.
authors: Shuu-Jiun
authors: SJ
authors: Wang
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging* / Q000378:metabolism; D051271:Headache Disorders, Secondary / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000639:trends*; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000000981:diagnostic imaging* / Q000378:metabolism; D000067490:Prescription Drug Overuse / Q000639:trends*
keywords: Magnetic resonance imaging; medication overuse; migraine; orbitofrontal cortex; voxel-based morphometry