title: Asymmetry in primary auditory cortex activity in tinnitus patients and controls.
abstract: Tinnitus is a bothersome phantom sound percept and its neural correlates are not yet disentangled. Previously published papers, using [(18)F]-fluoro-deoxyglucose positron emission tomography (FDG-PET), have suggested an increased metabolism in the left primary auditory cortex in tinnitus patients. This unilateral hyperactivity has been used as a target in localized treatments such as transcranial magnetic stimulation. The purpose of the current study was to test whether left-sided hyperactivity in the auditory cortex is specific to tinnitus or is a general characteristic of the auditory system unrelated to tinnitus. Therefore, FDG-PET was used to measure brain metabolism in 20 tinnitus patients and to compare their results to those in 19 control subjects without tinnitus. In contrast to our expectation, there was no hyperactivity associated with tinnitus. Nevertheless, the activity in the left primary auditory cortex was higher than in the right primary auditory cortex, but this asymmetry was present in both tinnitus patients and control subjects. In contrast, the lateralization in secondary auditory cortex was opposite, with higher activation in the right hemisphere. These data show that hemisphere asymmetries in the metabolic resting activity of the auditory cortex are present, but these are not associated with tinnitus and are a normal characteristic of the normal brain.
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands; Graduate School of Medical Sciences, Research School of Behavioral and Cognitive Neurosciences, University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands. Electronic address: l.i.geven@umcg.nl.
authors.forename: L I
authors.initials: LI
authors.lastname: Geven
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands; Graduate School of Medical Sciences, Research School of Behavioral and Cognitive Neurosciences, University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: de Kleine
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands.
authors.forename: A T M
authors.initials: AT
authors.lastname: Willemsen
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands; Graduate School of Medical Sciences, Research School of Behavioral and Cognitive Neurosciences, University of Groningen, P.O. Box 196, 9700 AD Groningen, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: van Dijk
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality / Q000502:physiology*; D006309:Hearing / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D014012:Tinnitus / Q000473:pathology*
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: BAs; Brodmann areas; FDG-PET; HL; IC; MFG; MNI; MRI; PAC; PET; PTA; ROI; SD; STGa; THI; WFU; Wake Forest University; [(18)F]-fluoro-deoxyglucose positron emission tomography; auditory cortex; hearing level; hemispheric dominance; inferior colliculus; laterality index; magnetic resonance imaging; middle frontal gyrus; montreal neurological institute; positron emission tomography; positron emission tomography (PET); primary auditory cortex; pure-tone average; rTMS; region-of-interest; repetitive transcranial magnetic stimulation; standard deviation; superior temporal gyrus, anterior division; tinnitus; tinnitus handicap inventory