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Open Access Highly Accessed Research article

Transcranial Magnetic Stimulation for the treatment of tinnitus: Effects on cortical excitability

Berthold Langguth1*, Tobias Kleinjung2, Joerg Marienhagen3, Harald Binder4, Philipp G Sand1, Göran Hajak1 and Peter Eichhammer1

Author Affiliations

1 Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany

2 Department of Otorhinolaryngology and Audiology, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany

3 Department of Nuclear Medicine, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany

4 Department of Medical Biometry and Statistics, University of Freiburg, Stefan-Meier-Strasse 26, 79104 Freiburg, Germany

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BMC Neuroscience 2007, 8:45  doi:10.1186/1471-2202-8-45

Published: 2 July 2007

Abstract

Background

Low frequency repetitive transcranial magnetic stimulation (rTMS) has been proposed as an innovative treatment for chronic tinnitus. The aim of the present study was to elucidate the underlying mechanism and to evaluate the relationship between clinical outcome and changes in cortical excitability. We investigated ten patients with chronic tinnitus who participated in a sham-controlled crossover treatment trial. Magnetic-resonance-imaging and positron-emission-tomography guided 1 Hz rTMS were performed over the auditory cortex on 5 consecutive days. Active and sham treatments were separated by one week. Parameters of cortical excitability (motor thresholds, intracortical inhibition, intracortical facilitation, cortical silent period) were measured serially before and after rTMS treatment by using single- and paired-pulse transcranial magnetic stimulation. Clinical improvement was assessed with a standardized tinnitus-questionnaire.

Results

We noted a significant interaction between treatment response and changes in motor cortex excitability during active rTMS. Specifically, clinical improvement was associated with an increase in intracortical inhibition, intracortical facilitation and a prolongation of the cortical silent period. These results indicate that intraindividual changes in cortical excitability may serve as a correlate of response to rTMS treatment.

Conclusion

The observed alterations of cortical excitability suggest that low frequency rTMS may evoke long-term-depression like effects resulting in an improvement of subcortical inhibitory function.