Research Article Structural Brain Changes Following Left Temporal Low-Frequency rTMS in Patients with Subjective Tinnitus Astrid Lehner, 1,2 Berthold Langguth, 1,2 Timm B. Poeppl, 1,2 Rainer Rupprecht, 1 Göran Hajak, 3 Michael Landgrebe, 1,4 and Martin Schecklmann 1,2 1 Department of Psychiatry and Psychotherapy, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany 2 Interdisciplinary Tinnitus Center, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany 3 Department of Psychiatry, Psychosomatics, and Psychotherapy, Social Foundation Bamberg, Buger Straße 80, 96049 Bamberg, Germany 4 Department of Psychiatry, Psychosomatics and Psychotherapy, kbo-Lech-Mangfall-Klinik Agatharied, Norbert-Kerkel-Platz, 83734 Hausham/Obb., Germany Correspondence should be addressed to Astrid Lehner; astrid.lehner@medbo.de Received 26 February 2014; Revised 6 May 2014; Accepted 14 May 2014; Published 3 June 2014 Academic Editor: Tobias Kleinjung Copyright © 2014 Astrid Lehner et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Repetitive transcranial magnetic stimulation (rTMS) of the temporal cortex has been used to treat patients with subjective tinnitus. While rTMS is known to induce morphological changes in healthy subjects, no study has investigated yet whether rTMS treatment induces grey matter (GM) changes in tinnitus patients as well, whether these changes are correlated with treatment success, and whether GM at baseline is a useful predictor for treatment outcome. herefore, we examined magnetic resonance images of 77 tinnitus patients who were treated with rTMS of the let temporal cortex (10 days, 2000 stimuli/day, 1 Hz). At baseline and ater the last treatment session high-resolution structural images of the brain were acquired and tinnitus severity was assessed. For a subgroup of 41 patients, additional brain scans were done ater a follow-up period of 90 days. GM changes were analysed by means of voxel based morphometry. Transient GM decreases were detectable in several brain regions, especially in the insula and the inferior frontal cortex. hese changes were not related to treatment outcome though. Baseline images correlated with change in tinnitus severity in the frontal cortex and the lingual gyrus, suggesting that GM at baseline might hold potential as a possible predictor for treatment outcome. 1. Introduction Subjective tinnitus is the phantom perception of a sound in the absence of a corresponding objective sound source. With about 25% of adults in the US having experienced a ringing in the ears at least once [1], transient tinnitus is a common phenomenon. About 10–15% of the world population experience tinnitus in its chronic form [2]. While the majority of those 10–15% gets used to their tinnitus and is able to lead a normal life, in 1–3% of the general population tinnitus is experienced as extremely bothersome and debilitating. It can severely afect patients’ everyday lives and is oten accompanied by psychiatric comorbidities such as depressive syndromes or sleep disturbances [2, 3]. In order to improve existing treatment options and also to generate new treatment strategies for subjective tinnitus, it is mandatory to broaden knowledge on the neural mechanisms underlying the tinnitus percept. More than 15 years ago it has been suggested [4, 5] and demonstrated [6] that tinnitus is related to alterations in the central nervous system. Furthermore, recent functional neuroimaging studies suggest [7–10] that, apart from the auditory cortex, widespread neural networks involving many diferent brain areas seem to be involved in the generation and maintenance of the phantom sounds as well as in the distress accompanied by the tinnitus percept [11, 12]. In addition to functional alterations within the brain, tinnitus has also been shown to be related to structural brain changes [13]. Hindawi Publishing Corporation Neural Plasticity Volume 2014, Article ID 132058, 10 pages http://dx.doi.org/10.1155/2014/132058