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Neural Plasticity
Volume 2014 (2014), Article ID 145943, 16 pages
http://dx.doi.org/10.1155/2014/145943
Research Article

Diffusion Imaging of Auditory and Auditory-Limbic Connectivity in Tinnitus: Preliminary Evidence and Methodological Challenges

1Laboratory of Integrative Neuroscience and Cognition, Department of Neuroscience, Georgetown University Medical Center, 3970 Reservoir Road NW, New Research Building, Washington, DC 20007, USA
2Center for Brain Plasticity and Recovery, Department of Neurology, Georgetown University Medical Center, 4000 Reservoir Road NW, Building D, Washington, DC 20007, USA
3Interdisciplinary Program in Neuroscience, Department of Neurology, Georgetown University Medical Center, 4000 Reservoir Road NW, Building D, Washington, DC 20007, USA
4Ahmanson-Lovelace Brain Mapping Center, Department of Neurology, 635 Charles Young Drive South, Suite 225, Los Angeles, CA 90095, USA
5Interdisciplinary Program in Neuroscience, Department of Neuroscience, Georgetown University Medical Center, 4000 Reservoir Road NW, Building D, Washington, DC 20007, USA

Received 4 April 2014; Accepted 26 May 2014; Published 22 June 2014

Academic Editor: Martin Meyer

Copyright © 2014 Anna Seydell-Greenwald et al. This 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.

Abstract

Subjective tinnitus, or “ringing in the ears,” is perceived by 10 to 15 percent of the adult population and causes significant suffering in a subset of patients. While it was originally thought of as a purely auditory phenomenon, there is increasing evidence that the limbic system influences whether and how tinnitus is perceived, far beyond merely determining the patient’s emotional reaction to the phantom sound. Based on functional imaging and electrophysiological data, recent articles frame tinnitus as a “network problem” arising from abnormalities in auditory-limbic interactions. Diffusion-weighted magnetic resonance imaging is a noninvasive method for investigating anatomical connections in vivo. It thus has the potential to provide anatomical evidence for the proposed changes in auditory-limbic connectivity. However, the few diffusion imaging studies of tinnitus performed to date have inconsistent results. In the present paper, we briefly summarize the results of previous studies, aiming to reconcile their results. After detailing analysis methods, we then report findings from a new dataset. We conclude that while there is some evidence for tinnitus-related increases in auditory and auditory-limbic connectivity that counteract hearing-loss related decreases in auditory connectivity, these results should be considered preliminary until several technical challenges have been overcome.