| Tinnitus is the perception of sound without corresponding external sources.It can influence patients’ sleep,attention,emotion,and then cause a series of problems that are not conducive to the work and life of patients.Due to the complex causes of tinnitus,domestic and foreign experts have not yet found a therapy that is effective for most tinnitus patients.Therefore,the exploration for tinnitus therapy is of great significance.As tinnitus is a kind of sound perception,external sound sources are usually applied in tinnitus sound therapy(TST)to change the perception and/or the response of patients to tinnitus in clinical research,so as to relieve tinnitus.The sound sources used in TST are usually noise(such as narrow-band noise or white noise)and music.Among them,TST that use noise-based sound sources have defects,such as uncomfortable auditory experience,limited scope of application,and inability to meet individualized and diversified requirements of patients.They affect feasibility of these therapies in clinic,so that the universal effectiveness of these therapies is low.To improve the comfort level of TST,scholars have proposed to use music to relieve tinnitus recently,which is music-tinnitus sound therapy(Music-TST).As a commonly used way of relaxation and decompression,music is safe and has no side effects.It is another way for TST.However,music used in current Music-TST is played repeatedly,which may cause bad memory and potentially negative emotions of patients.On the other hand,music in most Music-TST could not satisfy individualized preference requirements of tinnitus patients,which is not conducive to relaxation and decompression.Thus,the above-mentioned shortcomings affect the effective implementation of Music-TST.In recent years,the rapid development of signal processing,artificial intelligence,clinical medicine and inter-disciplinary research has brought new opportunities for the in-depth research of TST.Therefore,it is possible to explore a Music-TST that satisfies not only clinical requirements,but also individualized preference requirements of each patient.As mentioned above,Music-TST requires a specific music that is time-unlimited and not played repeatedly.At the same time,the specific music should also satisify individualized preference requirements of tinnitus patients,which is specific and preferred music(SPM).Herein,we propose a new Music-TST,which combines SPM and educational counseling to relieve tinnitus and is called specific and preferred music-tinnitus sound therapy(SPM-TST).Based on it,the following research is carried out with corresponding results obtained,which include:(1)A new automated method for developing SPM based on long short-term memory(LSTM)was proposed.Based on the specific and preferred requirements of Music-TST,and the shortcomings of existing methods for synthesizing specific music – pitch mutation and long pitch duration,a new method to automatically develop SPM based on LSTM was proposed.Predominant melody extraction technology was first applied to extract predominant melody of original music.Then the original music was segmented into music segments based on pre-set rules.Pitch value and pitch trend sequences of each music segment were extracted after that.LSTM was applied to learn the development laws of pitch and pitch trend in original music,train models to predict the development trends of subsequent music segments.At last,specific music was developed according to the predicted music segments.Based on different types of original music,the method could get corresponding type of specific music to meet individualized preference requirements of tinnitus patients,namely SPM.Results indicated that music developed by this new method could satisfy the specific and preferred requirements of Music-TST,avoid defects as mentioned above effectively,and have higher dynamic characteristics,which could be used in a clinical trial to verify the effectiveness in tinnitus relief.(2)A clinical trial was designed and carried out.Due to the shortcomings of specific music synthesized by previous methods,and the high complexity and long cycle of clinical trial itself,there was no clinical research about using SPM to relieve tinnitus.On the basis of satisfying the specific and preferred requirements of Music-TST for music,a new Music-TST was proposed,which was SPM-TST.Based on it,a clinical trial plan was designed,tinnitus patients were recruited,and a clinical trial was conducted.The clinical trial was approved by the Ethics Committee of West China Hospital of Sichuan University and registered with Chinese Clinical Trial Registry network.After that,the clinical trial was officially launched.In order to verify the effectiveness of SPM-TST on tinnitus relief,the clinical trial plan was set as follows.There were two observation groups,among which the intervention of experimental group was the combination of SPM and educational counseling(SPM-TST),and the intervention of control group was only educational counseling.The observation period of the two groups was three weeks.Before trial,tinnitus patients in the two groups received audiological tests.During observation,four tinnitus evaluations were conducted for tinnitus patients in the two groups.In addition,four physiological signal measurements were conducted for tinnitus patients in the experimental group.Finally,a total of 60 tinnitus patients were recruited to participate and complete the clinical trial,which lasted from April 2019 to January 2020.(3)Research on the effectiveness of SPM on tinnitus relief.Clinical audiology testing and tinnitus evaluation technology were applied to verify the effectiveness of SPM on tinnitus relief through clinical trial.Firstly,baseline data of tinnitus patients in the two groups before treatment were analyzed and compared.Results indicated that there was no statistical difference between the two groups,so as to eliminate the interference caused by difference in basedline data to results.Then tinnitus evaluation technology was applied to analyze tinnitus severity in different periods.After that,categories of tinnitus patients’ preferred music and the corresponding emotional evaluations were also analyzed.Results showed that SPM-TST was beneficial to tinnitus relief,and the benefit came not only from educational counseling,but also from SPM.At the same time,it was found that the efficacy was not related to a special category of music,which further comfirmed the importance of individualized preference satisfication in Music-TST.After intervention of SPM,tinnitus patients could perceive feelings that were conducive to tinnitus relief,reduce emotional distress,and then relieve tinnitus,which laid foundation for the research of SPM development methods,and provided evidence for the effectiveness of SPM in tinnitus relief.(4)Research on the physiological effect of SPM on tinnitus patients based on signal processing.Although SPM had been proven to be effective in tinnitus relief,its objective effect on physiology of tinnitus patients was still unclear.Thus,signal processing technology was applied to process and analyze various physiological signals(electrocardiogram,photoplethysmogram,respiration,and electromyogram signals),in an attempt to further observe the influence of SPM on physiological responses of tinnitus patients.Firstly,collected physiological signals were preprocessed,such as filtering out motion interference in electrocardiogram signals and electrocardiogram interference in electromyogram signals.Then various physiological signal features were extracted,such as heart rate,heart rate variability related features,pulse transit time,and the amplitude feature in electromyogram signals.After that,by comparing corresponding physiological features of tinnitus patients in different stages,under different types of SPM stimulation,and with different severity,the physiological effect of SPM on tinnitus patients was explored.Results indicated that SPM could relieve tinnitus by enhancing activities of parasympathetic nervous system,increasing overall heart rate variability,and reducing mental stress,which also provided additional support for the benefit of SPM for tinnitus relief.(5)A preferred music recommendation method based on acoustic signal feature extraction was proposed.Catering to the needs of long-term tinnitus treatment,a preferred music recommendation method for SPM-TST was proposed based on acoustic signal feature extraction.The aim of this method was to provide music that better matched individualized preference requirements of tinnitus patients in the follow-up and long-term treatment.Firstly,signal processing technology was applied to extract musical features from various aspects.Then Relief F algorithm was used to calculate the importance of musical features according to individualized preferences of different tinnitus patients.After that,musical features were sorted in a descending order of importance.Musical features that were effective for distinguishing preferred music were filterd according to the importance of features and correlations between features.At last,random forest and filterd musical features were used to train classification models to estimate the preference degree of unknown music.Results indicated that the preference degree of unknown music could be estimated in advance and audition time in SPM-TST could be effectively reduced by the proposed method,which was helpful to recommend and develop SPM for tinnitus patients in the long-term treatment,and implement SPM-TST more effectively.To the best of our knowledge,this thesis is the first systematic research on tinnitus treatment with SPM.Focusing on the specific and preferred requirements of Music-TST,signal processing technology,artificial intelligence technology,clinical audiology testing and tinnitus evaluation technology were applied to carry out a series of cross-disciplinary explorations.This thesis could not only effectively help patients alleviate tinnitus,but also help to reveal physiological effect of SPM on tinnitus patients.It laid a foundation for the effective implementation of SPM-TST.At the same time,this thesis was of great academic,practical and social significance,not only in aspects of acoustic signal processing,analysis and synthesis methods,but also in the sustainable and in-depth research on the intersection of signal processing technology and clinical research. |
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