title: Neuroanatomical heterogeneity of essential tremor according to propranolol response.
abstract: BACKGROUND
  Recent studies have suggested that essential tremor (ET) is a more complex and heterogeneous clinical entity than initially thought. In the present study, we assessed the pattern of cortical thickness and diffusion tensor white matter (WM) changes in patients with ET according to the response to propranolol to explore the pathogenesis underlying the clinical heterogeneity of ET.
  
  
  METHODS
  A total of 32 patients with drug naive ET were recruited prospectively from the Movement Disorders outpatient clinic. The patients were divided into a propranolol-responder group (n = 18) and a non-responder group (n = 14). We analyzed the pattern of cortical thickness and diffusion tensor WM changes between these two groups and performed correlation analysis between imaging and clinical parameters.
  
  
  RESULTS
  There were no significant differences in demographic characteristics, general cognition, or results of detailed neuropsychological tests between the groups. The non-responder group showed more severe cortical atrophy in the left orbitofrontal cortex and right temporal cortex relative to responders. However, the responders exhibited significantly lower fractional anisotropy values in the bilateral frontal, corpus callosal, and right parietotemporal WM compared with the non-responder group. There were no significant clusters where the cortical thickness or WM alterations were significantly correlated with initial tremor severity or disease duration.
  
  
  CONCLUSIONS
  The present data suggest that patients with ET have heterogeneous cortical thinning and WM alteration with respect to responsiveness to propranolol, suggesting that propranolol responsiveness may be a predictive factor to determine ET subtypes in terms of neuroanatomical heterogeneity.
authors.affiliation: Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seok Jong
authors.initials: SJ
authors.lastname: Chung
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Seoul, Korea.
authors.forename: Hunki
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Seoul, Korea.
authors.forename: Dong-Kyun
authors.initials: DK
authors.lastname: Lee
authors.affiliation: Department of Neurology, Yonsei University Wonju College of Medicine, Wonju, Korea.
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Hong
authors.affiliation: Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Mun-Kyung
authors.initials: MK
authors.lastname: Sunwoo
authors.affiliation: Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young H
authors.initials: YH
authors.lastname: Sohn
authors.affiliation: Department of Biomedical Engineering, Hanyang University, Seoul, Korea.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Phil Hyu
authors.initials: PH
authors.lastname: Lee
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D016880:Anisotropy; D002540:Cerebral Cortex / Q000187:drug effects / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D020329:Essential Tremor / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011379:Prognosis; D011433:Propranolol / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists; D011433:Propranolol