Tinnitus is a common experience with up to one third of the adult population experiencing it at some time in their life. Less than 1% of the adult population have tinnitus of sufficient severity to affect their quality of life seriously (although up to 8% may seek medical advice about it). Much of the severity of tinnitus relates to the individuals' psychological response to the abnormal tinnitus signal. The prevalence of tinnitus increases in association with high frequency hearing loss. There is, unfortunately, no diagnostic test that either confirms the presence of tinnitus or its severity. Currently there is no satisfactory severity grading system. A five-point severity grading scheme is therefore proposed and the entry criteria detailed. The five severity points are: slight, mild, moderate, severe and catastrophic. Categorization as 'severe' or 'catastrophic' should be, by epidemiological definition, very rare. General guidance, theory and evidential support are contained within.

Many people who complain of tinnitus say that the noises impair their mental concentration. This complaint was investigated by self-report (primarily the Cognitive Failures Questionnaire) and by means of five cognitive tasks, four presented via laptop computer and one given manually. The tasks measured performance under single- and dual-task conditions and included tests of sustained attention, reaction time, verbal fluency and immediate and delayed memory. Two groups of outpatients attending audiological clinics (tinnitus, n = 43; hearing impairment, n = 17) were compared with non-clinical volunteers (n = 32). The results replicated earlier findings that tinnitus outpatients report significantly more everyday cognitive failures than do controls. The tinnitus group responded significantly more slowly than the two control groups on the variable fore-period reaction time task under dual-task conditions. In general, comparisons between the groups on other tasks showed equivalent performance, but both clinical groups performed more poorly than non-clinical controls on verbal fluency. We conclude that cognitive inefficiency in tinnitus participants is related to the control of attentional processes, consistent with our earlier theoretical speculation about the nature of tinnitus complaint and with published findings on the effects of chronic pain on cognitive processes.

The importance of psychological factors in tinnitus distress has been formally recognized for almost three decades. The psychological understanding of why tinnitus can be a distressing condition posits that it becomes problematic when it acquires an emotive significance through cognitive processes. Principle therapeutic efforts are directed at reducing or removing the cognitive (and behavioral) obstacles to habituation. Here, the evidence relevant to a new psychological model of tinnitus is critically reviewed. The model posits that patients’ interpretations of tinnitus and the changes in behavior that result are given a central role in creating and maintaining distress. The importance of selective attention and the possibility that this leads to distorted perception of tinnitus is highlighted. From this body of evidence, we propose a coherent cognitive-behavioral model of tinnitus distress that is more in keeping with contemporary psychological theories of clinical problems (particularly that of insomnia) and which postulates a number of behavioral processes that are seen as cognitively mediated. This new model provides testable hypotheses to guide future research to unravel the complex mechanisms underpinning tinnitus distress. It is also well suited to define individual symptomatology and to provide a framework for the delivery of cognitive-behavioral therapy.

There are yet relatively few published studies on cognitive functioning in tinnitus patients. Most research has been conducted by a few separate research groups. However, the available studies clearly implicate an important role of cognitive processes at different levels from basic cognitive function to more conscious appraisal of the consequences of tinnitus. Finally, a tentative model of the road from tinnitus generation to annoyance via cognitive function is suggested.