Clinical Aspects of Tinnitus- Course, Cognition, PET, and the Internet
Abstract: The purpose of this thesis was to develop novel ways to study tinnitus, to investigate the course of tinnitus, and to study the effects of cognitive-behaviour therapy on tinnitus related distress. Data from 377 tinnitus patients were collected.A group of 216 patients completed audiological measures and were assessed in a structured interview. The Klockhoff and Lindblom's grading system was used and its inter-rater reliability assessed in a subsample showing a high degree of correspondence. A discriminant analysis showed that a substantial proportion of patients could be correctly classified into grade II or III, by measures of pitch, minimal masking level of tinnitus, avoidance of situations because of tinnitus, and tolerance in relation to onset.Using tests developed in cognitive psychology, it was found that tinnitus patients had impaired performance. There was no evidence for an attentional bias towards tinnitus related words using a computerized emotional Stroop task, but masking sounds of an "on-and-off" character were more disruptive than constant masking when patients performed the digit-symbol test. It is suggested that tinnitus distress may be increased by the 'changing-state' character of the tinnitus signal, or alternatively by intermittent masking sounds.In a case-study a patient received an i.v. injection of lidocaine while Positron Emission Tomograpy was conducted. The brain activity associated with tinnitus included the left primary, secondary and integrative auditory brain areas, as well as right paralimbic areas related to negative feelings. The precuneus (Brodmann area 7) might be a brain area involved in the aversiveness associated with tinnitus.Using a tinnitus questionnaire as the dependent measure it was found that tinnitus maskability at admission predicted distress at follow-up for an average of five years following admission. Some improvement in tinnitus occurred over time, but this was more evident in patients who had received a cognitive-behavioural treatment program.The effect of an Internet based cognitive-behavioural self-help treatment program for tinnitus was investigated showing a high dropout rate, but with positive results in that the treated patients improved.
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