Auditory System and Plasticity: fMRI/MEG

Lead Research Organisation: MRC Institute of Hearing Research

Abstract

Tinnitus is a hearing disorder where people perceive a sound in one or both ears. It is commonly, but not always, associated with hearing loss. The phantom sound sensation is associated with abnormal patterns of brain activity. Understanding these brain responses will help to define the mechanism of tinnitus and inform the best ways in which the disorder may be treated.|In the first stage we will assess the hearing ability in all patients and using a computerised task will attempt to identify the precise quality and loudness of the sound. In the next stage we use non-invasive brain imaging technique of MEG to investigate the differences between tinnitus patients and non?tinnitus controls in terms of the location and the pattern of brain activity, both at rest and when listening to sounds. The brains transient rhythms associated with activation of populations of neurons will be recorded with MEG and analysed using special techniques. |The outcome of this study will tell us where in the brain is active during tinnitus and what sort of activity is taking place and it has the potential to direct successful treatment for this disorder in the future.

Technical Summary

Persistent tinnitus that affects 5-15% of the population is the sensation of sound when no external sound is present. It can occur in normally hearing subjects and as a symptom of pathology, such as sensorineural hearing loss. To gain a better understanding of the pathophysiology in tinnitus we are measuring cortical characteristics of the abnormality by non-invasive brain imaging of subjects using magnetoencephalography after extensive assessment of the characteristics of their tinnitus. The focus is on objective measures of tinnitus-related activity that will inform the classification of different subtypes of the disorder and to seek correlations with neurological signatures of brain activity. We are specifically testing recent hypotheses that abnormal brain rhythms in tinnitus subjects reflect changes in thalamocortical feedback. |The first stage will address whether spatio-temporal patterns of spontaneous and sound-induced rhythmic activity differ between patients with tinnitus and normal (age- and hearing- matched) controls. The second stage will address whether these measures are sensitive to some of the key defining differences between subgroups of tinnitus patients, such as those based on aetiology (e.g. trauma, hearing loss, or unknown) and laterality (unilateral or bilateral).|All participants will undergo a number of psychoacoustic tests including audiometry evaluation and tinnitus assessment in order to obtain a quantified measure of the tinnitus sound and its loudness. We will also assess whether tinnitus can be masked using a wide band white noise stimulus. In the second stage of the study we will use the sounds identified during the tinnitus evaluation to examine the brains responses to different tones, including one at the audiometric edge of the hearing loss and another which corresponds to the tinnitus sound. The results will indicate whether cortical plasticity can be related to tinnitus. |Additionally, we will attempt to identify brain regions that respond to the masker when tinnitus is masked and the oscillatory rhythms at these precise locations will be investigated for differences with non-tinnitus controls. The temporal characteristics of the signals will indicate which specific signals are associated with cortical abnormality in tinnitus.|Overall, the results will provide information on specific cortical activity associated with tinnitus and its relationship to the auditory profile of each patient and may help to identify successful clinical intervention for this disorder in the future.

Publications

10 25 50
 
Description MEG investigation of Tinnitus 
Organisation University of Nottingham
Department School of Physics and Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution Provision of data and collaboration on data analysis
Collaborator Contribution Suggestion of methods for data analysis
Impact Accepted Abstract to ARO; Research paper in Hearing Research (2013) and a review in 2014. Functional brain imaging with MEG and structural MRI.
Start Year 2009
 
Description Invited lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact This was part of a relaunch event at the Brain and Body Centre at the University of Nottingham

Allowed interaction with other scientists and inspired a potential collaboration for the future.
Year(s) Of Engagement Activity 2012