Arthur Peter Wunderlich PhD, Presenter: Nothing to Disclose

Carlos Schönfeldt-Lecuona MD, Abstract Co-Author: Nothing to Disclose

Kristina Liener MD, Abstract Co-Author: Nothing to Disclose

Edgar Bachor, Abstract Co-Author: Nothing to Disclose

Wolfgang Freund MD, Abstract Co-Author: Nothing to Disclose

To study cerebral processes related to tinnitus by comparing fMRI activation patterns of a frequency discrimination task in tinnitus patients and age-matched healthy volunteers.

Seventeen tinnitus patients and nine healthy, normally hearing volunteers were scanned with fMRI. Tones of 3 kHz as well as 2 % above or below this center frequency were presented as 50 ms beeps at a rate of 5 per second blockwise together with silence blocks of identical length in pseudorandomized order. Subjects’ attention was directed to the tones by the task of discriminating tones by frequency. On a Siemens Magnetom Vision MR scanner at 1.5 T, we got 37 slices covering the whole brain with single-shot EPI at TE/TA 66/4000 ms. Data processing and analysis was performed with SPM 99. In each subject, all tones were contrasted against silence at p=0.05 corrected. A group analysis was performed to visualize main effects of both groups as well as differential effects between groups (p<0.001 uncorrected).

Subjects of both groups showed activation not only in primary and secondary auditory cortex but also in lateral parts of right prefrontal and left parietal areas, Brodmann Areas (BA) 6 and BA 3. For healthy subjects, prefrontal activation was less pronounced than in patients. The location of prefrontal activation was variable in patients, therefore, the patient’s group analysis showed only activation of the parietal lobe and secondary auditory areas. Prefrontal activation in controls was significant in group analysis. The differential contrast controls minus patient group revealed activation of subcortical areas corresponding to caudate nucleus to be superior in healthy controls. The opposite contrast demonstrated higher activation levels for patients in mainly two left-hemispheric regions: a parietal region, BA 3 or primary sensory cortex SI, and the fusiform gyrus, BA 19, which has been implicated in discrimination tasks and fear specific activation.

By presenting intermittent tones at different frequencies, we were able to detect activations beside primary auditory areas in single subjects as well as group differences between normal hearing subjects and tinnitus patients.

Wunderlich, A, Schönfeldt-Lecuona, C, Liener, K, Bachor, E, Freund, W, Tinnitus-specific Activations Revealed by fMRI.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4413721.html