Quantitative electroencephalography for tinnitus--a means for data collection, analysis, and translation.

Quantitative electroencephalography (QEEG) is the technique whereby brain electrical activity in individuals is recorded as they sit quietly with their eyes closed. The electrical activity is quantified with a variety of statistical measures to characterize the huge variation in combinations of emissions from the brain. Neuroscience research has demonstrated that such resting brain activity measures may be consistently altered in conditions such as depression or dementia. A wide variety of ongoing efforts are attempting to find characterizations that reliably denote other neurological conditions. In research on tinnitus, a variety of groups have been working to characterize QEEG changes related to the presence of the abnormal sensation of sound and to the emotional distress associated with it. QEEG changes related to the tinnitus percept are in the gamma electroencephalography (EEG) band recorded from temporal lobes. Clinical depression has a reliable marker in the depression of posterior cerebral alpha EEG frequency band activity, and this same activity is found in patients with tinnitus of the severe disabling type. In the past, QEEG has suffered from inconsistent recording methods, closed data sets, and noncompatible analytical techniques. Now in the modern era, when reliable data sets are shared and hardware and software are less expensive, regular use of QEEG will be clinically important. Those prepared to make the minor investment in equipment and training will reap the benefit of objective measures of brain activity. Knowing patterns of QEEG activity related to tinnitus and its associated depression will help clinicians better manage these patients.