Project Details
Projekt
Dynamic range adaptation in chronic tinnitus
Subject Area
Otolaryngology, Phoniatrics and Audiology
Clinical Psychiatry, Psychotherapy, Child and Adolescent Psychiatry
Clinical Psychiatry, Psychotherapy, Child and Adolescent Psychiatry
Term
from 2013 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 243145978
The term 'tinnitus' refers to a class of auditory phantom sensations that many people in industrialized countries are affected by, some of them severly. In many cases, the condition originates with damage to the inner ear. It is therefore often associated with hearing loss usually affecting the upper part of the range of hearing. The peripheral injury results in numerous central functional and structural changes. There is no causal treatment, as the details of the pathophysiology are largely unknown. Tinnitus may qualify as a hyperactivation disorder. Hyperactivation as indexed by the amplitude of the auditory evoked MEG/EEG signal is correlated with tinnitus loudness and tinnitus intrusiveness. However, the specifics of the hypothetical mechanisms - the downregulation of inhibition and the upregulation of system sensitivity and system gain - have not been worked out. Earlier and current variants of the sensitivity/gain adjustment hypothesis of tinnitus fail to acknowledge that normal and ubiquitous dynamic range adaptation of stimulus intensity coding involves second-to-second and faster changes in system sensitivity and system gain. While it remains a logical possibility that dynamic range adaptation of stimulus intensity coding and sensitivity/gain adjustment associated with tinnitus are independent processes, here we propose to study the hypothesis that tinnitus-specific sensitivity/gain adjustment adversely affects the dynamic range adaptation of intensity coding. Furthermore, we propose to study the complementary question of if and how tinnitus affects the early rapid detection of stimulus intensity change. The experiments will make use of magnetoencephalography (MEG) and the measurement of middle-latency auditory evoked magnetic fields, source localization and, in order to study tinnitus-related changes in functional and structural networks that could be the neural correlate of changes in dynamic range adaptation, spatially distributed (beamformer) models and source coherence measures together with magnetic resonance diffusion tensor imaging (MR DTI) and tractographic analysis.
DFG Programme
Research Grants
