Quantitative electroencephalography power analysis in subjective idiopathic tinnitus patients: a clinical paradigm shift in the understanding of tinnitus, an electrophysiological correlate.Int Tinnitus J. 2006; 12(2):121-31.IT
We report a descriptive analysis-interpretation of quantitative electroencephalography (QEEG) data for the metric of power in patients with tinnitus of the severe disabling type (N = 61). The results are based on a statistical analysis of the data compared to a normative database as calculated in Z scores, controlling for the factors of age, gender, IQ, and the like.
We analyzed the QEEG data for the metric of power to measure (1) the number of significant recordings, normal and abnormal; (2) the significant recordings by electrode recording sites; (3) distribution of the electroencephalographic (EEG) frequency bands; and (4) occurrence of the EEG frequency bands correlated with the electrode recording sites. In the analysis of the occurrence of the EEG frequency bands by electrode recording area, we corrected for the number of recording sites.
We recorded normal power recordings in 20 of 61 patients (32.8%) and abnormal power recordings in 41 of 61 patients (67.2%); power distribution by frequency band in 41 of 61 patients,revealing the number of significant recordings of delta (119), alpha (69), beta (91), and theta (17); and the power distribution by location for all frequencies, which were revealed as recording site activity in the frontal greater than in the temporal sites, which in turn was greater than in the parietal site, and equal activity in parietal, occipital, and central sites. The analysis of the occurrence of the EEG frequency bands by electrode recording area as corrected for the number of recording sites reinforced our initial results.
Z-score analyses of QEEG recordings--based on a large normative database--for the metric of power for patients having tinnitus of the severe disabling type (N = 61) revealed statistically significant abnormalities in frontal greater than temporal electrode recording sites. We reported no difference between male and female tinnitus patients in the number of abnormal power QEEG recordings. However, we observed significant differences in the average Z scores between males and females in the alpha and theta bands. The results suggest multiple central electrophysiological correlates for different clinical types of tinnitus identifiable with QEEG, for the metric of power, by frequencies of brain activity of delta greater than beta greater than alpha greater than theta bands of activity, reflecting physiologically the individuality of brain function and clinically the heterogeneity of the symptom of tinnitus for tinnitus patients. Clinical interpretation of the QEEG data in terms of brain function in a tinnitus patient, with a focus on theories of a neuroanatomical homeostatic system that regulates baseline levels of local synchrony in multiple neuronal assemblies and on theories of consciousness, introduces a paradigm switch in our clinical understanding of the symptom of tinnitus and an application for tinnitus diagnosis and treatment.