title: The impact of auditory cortex activity on characterizing and treating patients with chronic tinnitus--first results from a PET study.
abstract: CONCLUSIONS
  Unilaterally increased metabolic activity within the primary auditory cortex (PAC) represents a robust finding in tinnitus patients. Targeting these hyperactive areas with image-guided low frequency repetitive transcranial magnetic stimulation (rTMS) results in subjective tinnitus reduction. More pronounced activation of the PAC predicted higher resistance to rTMS.
  
  
  OBJECTIVE
  [18F]deoxyglucose (FDG)-positron emission tomography (PET) was used to assess metabolic activity within the central auditory system in tinnitus. The study investigated whether patterns of neuronal activity correlate with clinical features or may be used for the prediction of treatment outcome.
  
  
  METHODS
  Twenty patients with chronic tinnitus underwent PET imaging followed by low frequency rTMS treatment. Neuroimaging data were compared with clinical parameters and treatment outcome.
  
  
  RESULTS
  PET data demonstrated an asymmetric activation of the central auditory system. Seventeen patients revealed increased activity of the primary auditory cortex on the left side, three on the right side. The extent of hypermetabolic activity prior to treatment correlated significantly with tinnitus reduction after rTMS, but not with clinical characteristics such as tinnitus severity, tinnitus laterality or tinnitus duration.
authors.affiliation: Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Germany. Berthold.Langguth@medbo.de
authors.forename: Berthold
authors.initials: B
authors.lastname: Langguth
authors.forename: Peter
authors.initials: P
authors.lastname: Eichhammer
authors.forename: Antje
authors.initials: A
authors.lastname: Kreutzer
authors.forename: Peter
authors.initials: P
authors.lastname: Maenner
authors.forename: Joerg
authors.initials: J
authors.lastname: Marienhagen
authors.forename: Tobias
authors.initials: T
authors.lastname: Kleinjung
authors.forename: Philipp
authors.initials: P
authors.lastname: Sand
authors.forename: Göran
authors.initials: G
authors.lastname: Hajak
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000378:metabolism* / Q000503:physiopathology*; D002908:Chronic Disease; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014012:Tinnitus / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D050781:Transcranial Magnetic Stimulation / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18