ABSTRACT
BACKGROUND AND OBJECTIVES: Mutational dysphonia, also referred to as mutational falsetto, is defined as the dysphonia that continuously have high pitch after adolescence. The aims of this study were to investigate the acoustic and electroglottographic characteristics of mutational dysphonia before and after voice therapy and to identify the factors that may be of help in its treatment. SUBJECTS AND METHOD: The clinical records of 15 patients with mutational dysphonia were reviewed, and analyses of their voice records were carried out with the help of Lx Speech Studio studio (Laryngograph Ltd, London, UK) program. RESULTS: After voice therapy was combined with manual compression method, the voices of the subjects were lowered in pitch and also improved in voice quality. Furthermore, we were able to classify the mutational dysphonia into 4 categories according to diplophonia and closed quotients. The most common type among the categories was bimodal distribution of fundamental frequency, or so-called diplophonic, accompanied with low closed quotient-falsetto voice-at high frequency area. However, the results also showed that all cases of mutational dysphonia can not be generalized simply as falsetto voice. The effect of the therapy for each type was different, and we could assume that in the cases with diplophonia accompanied with non-trained falsetto voice, it is expected that it can be treated readily. CONCLUSION: The diplophonia and closed quotient, which were easily analyzed by using Lx Speech Studio program, are important factors which help to classify the mutational dysphonia, choose the treatment options, monitor the efficacy of therapy, and estimate the prognosis of diseases.