Temporo-insular enhancement of EEG low and high frequencies in patients with chronic tinnitus. QEEG study of chronic tinnitus patients
1 Institute of Neuroinformatics, ETHZ/UNIZH, Winterthurerstrasse 190, 8057 Zurich, Switzerland
2 University Hospital Zurich, Laboratory for Functional Neurosurgery, CH-8091 Zurich, Switzerland
3 Department of Psychology, University of Konstanz, D-78464 Konstanz, Germany
4 Center for Integrative Human Physiology, University of Zurich, CH-0857 Zurich, Switzerland
BMC Neuroscience 2010, 11:40 doi:10.1186/1471-2202-11-40Published: 24 March 2010
The physiopathological mechanism underlying the tinnitus phenomenon is still the subject of an ongoing debate. Since oscillatory EEG activity is increasingly recognized as a fundamental hallmark of cortical integrative functions, this study investigates deviations from the norm of different resting EEG parameters in patients suffering from chronic tinnitus.
Spectral parameters of resting EEG of male tinnitus patients (n = 8, mean age 54 years) were compared to those of age-matched healthy males (n = 15, mean age 58.8 years). On average, the patient group exhibited higher spectral power over the frequency range of 2-100 Hz. Using LORETA source analysis, the generators of delta, theta, alpha and beta power increases were localized dominantly to left auditory (Brodmann Areas (BA) 41,42, 22), temporo-parietal, insular posterior, cingulate anterior and parahippocampal cortical areas.
Tinnitus patients show a deviation from the norm of different resting EEG parameters, characterized by an overproduction of resting state delta, theta and beta brain activities, providing further support for the microphysiological and magnetoencephalographic evidence pointing to a thalamocortical dysrhythmic process at the source of tinnitus. These results also provide further confirmation that reciprocal involvements of both auditory and associative/paralimbic areas are essential in the generation of tinnitus.