title: Neuroanatomical abnormalities in chronic tinnitus in the human brain.
abstract: In this paper, we review studies that have investigated brain morphology in chronic tinnitus in order to better understand the underlying pathophysiology of the disorder. Current consensus is that tinnitus is a disorder involving a distributed network of peripheral and central pathways in the nervous system. However, the precise mechanism remains elusive and it is unclear which structures are involved. Given that brain structure and function are highly related, identification of anatomical differences may shed light upon the mechanism of tinnitus generation and maintenance. We discuss anatomical changes in the auditory cortex, the limbic system, and prefrontal cortex, among others. Specifically, we discuss the gating mechanism of tinnitus and evaluate the evidence in support of the model from studies of brain anatomy. Although individual studies claim significant effects related to tinnitus, outcomes are divergent and even contradictory across studies. Moreover, results are often confounded by the presence of hearing loss. We conclude that, at present, the overall evidence for structural abnormalities specifically related to tinnitus is poor. As this area of research is expanding, we identify some key considerations for research design and propose strategies for future research.
authors.affiliation: MRC Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom. Electronic address: peyman@ihr.mrc.ac.uk.
authors.forename: Peyman
authors.initials: P
authors.lastname: Adjamian
authors.affiliation: National Institute for Health Research (NIHR), Nottingham Hearing Biomedical Research Unit, University of Nottingham, Ropewalk House, 113 The Ropewalk, Nottingham NG1 5DU, United Kingdom; Otology and Hearing Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Hall
authors.affiliation: MRC Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Palmer
authors.affiliation: MRC Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Allan
authors.affiliation: National Institute for Health Research (NIHR), Nottingham Hearing Biomedical Research Unit, University of Nottingham, Ropewalk House, 113 The Ropewalk, Nottingham NG1 5DU, United Kingdom; Otology and Hearing Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
authors.forename: Dave R M
authors.initials: DR
authors.lastname: Langers
mesh_terms: D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D002908:Chronic Disease; D006801:Humans; D008959:Models, Neurological; D014012:Tinnitus / Q000473:pathology* / Q000503:physiopathology
keywords: Gating mechanism; Limbic system; Prefrontal cortex; Tinnitus; Tractography; Voxel-based morphometry