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Recent advances in functional imaging have opened new possibilities for understanding tinnitus. Especially, positron emission tomography (PET) has been increasingly used in the last two decades to identify cortical networks, which are involved in the generation of various forms of chronic tinnitus. PET studies have confirmed that the anatomical location of the anomalies that cause many forms of tinnitus are regions of the brain that are normally involved in auditory processing as well as regions engaged in emotional processing. These findings have contributed to the development of new more causally oriented treatment strategies. In particular, identification of increased activity of the auditory cortex by PET has prompted the use of focal brain stimulation techniques such as electrical or transcranial magnetic stimulation in treatment of tinnitus. PET studies that map distinct neurochemical pathways and receptors by the use of specific ligands may in the future provide new possibilities for pharmacologically based treatment of some forms of tinnitus.

A growing number of self-report measures for the evaluation of tinnitus severity has become available to research and clinical practice. This has led to an increased awareness of depression and personality as predictors of tinnitus severity in addition to loudness and other psychoacoustic measures. However, the net impact of personality dimensions on tinnitus ratings has not been investigated when the effect of depressed mood is controlled. In the present study, we demonstrate the role of the big five personality traits, 'Neuroticism', 'Extraversion', 'Openness', 'Agreeableness', and 'Conscientiousness', in affecting scores on two standard instruments for grading tinnitus-related complaints, the tinnitus handicap inventory (THI), and the tinnitus questionnaire (TQ). When 72 individuals with chronic tinnitus were examined, 'Agreeableness' negatively correlated with THI scores (p=.003), whereas the anxiety trait 'Neuroticism' correlated both with depressive symptomatology (p

Results of neurophysiological and neuroimaging studies suggest that some forms of chronic tinnitus can be regarded to be "hyperexcitability syndromes", caused by abnormal focal brain activity. Low frequency repetitive magnetic stimulation (rTMS) is an efficient method to selectively reduce the abnormally increased activity in distinct cortical areas. An increasing amount of clinical data suggest that low frequency rTMS might be an effective therapy that is directed at the cause of some forms of chronic tinnitus. To further explore the underlying neurobiological mechanisms we investigated the effect of rTMS on cortical excitability in healthy human subjects using the protocol, which has been successfully used for the treatment of tinnitus. We determined different parameters of motor cortex excitability (resting motor threshold, RMT; active motor threshold, AMT; short intracortical inhibition, ICI; short intracortical facilitation, ICF; and the duration of the cortical silent period, CSP) before and after 5 days of low frequency rTMS (2000 stimuli/day at 110% of RMT) over the left auditory cortex. Five sessions of low frequency rTMS resulted in a significant prolongation of the CSP. All other signs of cortical excitability that we studied remained unchanged. These findings suggest, that low frequency rTMS may evoke long-term depression (LTD)-like effects resulting in enhancement of subcortical inhibition.