博士 / 國立成功大學 / 醫學工程研究所碩博士班 / 94 / Subjective tinnitus is a very common symptom in the medical horizon. The prevalence of tinnitus in adults ranges between 10.1 % and 14.5% and evidence shows that tinnitus is positively correlated with age. Despite a variety of therapeutic modalities, quantitative measurement and consistent effective treatment remain elusive in recent years. The phenomenon that tinnitus could be masked with external sounds was initially applied in tinnitus treatment around 1975. The successful masking rate has been reported from 45 % to 69 %. Later, tinnitus retraining therapy (TRT) was introduced to facilitate the process of tinnitus habituation based on the neurophysiological model of tinnitus and neuroplasticity of auditory nerve system. But there is still uncertainty of these two sound therapies about their long-term effects on auditory system, particularly for these modalities to relieve rather than to cure tinnitus and for their lengthy courses of treatment.
This research is motivated by the increasing prevalence of tinnitus worldwide and the lack of quantitative evaluation and prescription of tinnitus treatment. With the advent of computer technology, electronics and digital signal processing, new medical techniques are likely to be developed for quantitative evaluation of tinnitus and for quantitative prescription on noise therapy. Therefore, the purpose of this research is to design and develop a clinical useful system for quantitatively investigating the frequency band and intensity of tinnitus noises. More specifically, this research is aimed to (1) design a PC-based platform for evaluation and rehabilitation on tinnitus; (2) develop a prescription program for tinnitus treatment through quantitatively investigating frequency range and intensity parameters of tinnitus characteristics; (3) comparatively evaluate the clinical efficacy of conventional wide-band noises and customized narrow-band noises on tinnitus treatment. This research is to test the hypothesis that through integrated neurophysiological mechanism of tinnitus, auditory neuroplasticity and modern digital signal processing technology, clinical tinnitus can be measured more objectively and treated more effectively.
This research is divided into two stages of experiments. Experiment stage I is to design a PC-based tinnitus evaluation system through GUI system programming, which contains a clinical database and four functional modules based on clinical procedure and psychoacoustic reaction of tinnitus. Pure tone threshold functional module is designed to generate pure tones for hearing threshold evaluation. Preset narrow-band noise functional module is designed to provide preset band noises for frequency and loudness matching. Tunable band noise functional module is designed to provide fine tuning for the preset narrow-band noise and Customized noise generator functional module is to generate the digital file of the prescribed noise for tinnitus treatment. System calibration and preliminary clinical application to tinnitus subjects are also conducted. Experiment stage II is to quantitatively investigate the effects of tinnitus parameters on tinnitus. Totally 25subjects suffering from persistent tinnitus were recruited from NCKU Hospital and randomly assigned into the exp. Group (13 subjects) who underwent TRT with sound therapy using customized narrow-band noises and the control group (12 subjects) who underwent TRT with sound therapy using conventional wide-band noises for six months. Two-way ANOVA with one factor repeated measurements is used to statistically analyze the MML and MP of tinnitus psychoacoustic parameters in loudness and THI scores of tinnitus severity from questionnaires. The treatment factor includes exp. and control groups, and the time factor includes 4 levels of before treatment, 2 months, 4 months and 6 months after treatment. The results are used to assess comparatively the clinical efficacy of two groups on tinnitus treatment.
In experiment stage I, the PC-based prototype of tinnitus evaluation and prescription system has been completely designed. In the tinnitus matching process, the frequency matching rate is 95% (152 out of 160 subjects) and the self-ranked median score is 7 (ranging from 0 to 10). The overall successful matching rate for both frequency and loudness is 83%. The results of regression analysis indicate that the MML is linear to the MP level statistically ( C.C. =0.9 and p< 0.0001). The tinnitus evaluation system is likely to be useful in the tinnitus matching procedure clinically.
The analytical results of tinnitus psychoacoustic parameters in loudness show that the experiment group has significantly lower both MML and MP dB values than the control group (MML: F=6.7, p=0.016; MP: F= 5.9, p=0.023). The time effects are significant on both MML and MP dB values (p < 0.05). The results from Sheffe’s multiple comparison of post test indicate that the MML dB values of both after four- and six-months treatments are significantly lower than that of before treatment (p < 0.05) for the experiment and control groups. The MP dB value after six-months treatment is significantly lower than that of before treatment in the experiment group, but there is no time effect on the MP value for the control group. There is no interaction between time and treatment factors (MML: F= 0.724, p = 0.541; MP: F= 2.151, p = 0.102).
The THI score of experiment group is not significantly different from that of control group (p > 0.05). The time effects are significant on the THI scores for both groups. The results from Sheffe’s multiple comparison of post test indicate that the THI scores of both after four- and six-months treatments are significantly lower than that of before treatment (p < 0.05) for the experiment and control groups. There was no interaction between time and treatment factors (F= 0.476, p = 0.7). With the help of a digital tinnitus evaluation system with well-developed matching protocol, subjective tinnitus can be more assessed objectively and quantitatively. This system is proved to be reliable and feasible in clinical use. Derived from tinnitus matching parameters in frequency and intensity, customized noise could be applied to the sound therapy for Tinnitus Retraining Therapy. Conclusively, customized narrow-band noises are more effective in lowering tinnitus loudness and may provide a viable treatment option of tinnitus.
| Identifer | oai:union.ndltd.org:TW/094NCKU5530006 |
| Date | January 2005 |
| Creators | Chii-Yuan Huang, 黃啟原 |
| Contributors | Kao-Chi Chung, 鍾高基 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 83 |
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