The effects of size and type of vocal fold polyp on some acoustic voice parameters

Background: Vocal abuse and misuse would result in vocal fold polyp. Certain features define the extent of vocal folds polyp effects on voice acoustic parameters. The present study aimed to define the effects of polyp size on acoustic voice parameters, and compare these parameters in hemorrhagic and non-hemorrhagic polyps. Methods: In the present retrospective study, 28 individuals with hemorrhagic or non-hemorrhagic polyps of the true vocal folds were recruited to investigate acoustic voice parameters of vowel/ æ/ computed by the Praat software. The data were analyzed using the SPSS software, version 17.0. According to the type and size of polyps, mean acoustic differences and correlations were analyzed by the statistical t test and Pearson correlation test, respectively; with significance level below 0.05. Results: The results indicated that jitter and the harmonics-to-noise ratio had a significant positive and negative correlation with the polyp size (P=0.01), respectively. In addition, both mentioned parameters were significantly different between the two types of the investigated polyps. Conclusion: Both the type and size of polyps have effects on acoustic voice characteristics. In the present study, a novel method to measure polyp size was introduced. Further confirmation of this method as a tool to compare polyp sizes requires additional investigations. © 2018, Shiraz University of Medical Sciences. All rights reserved

The effects of size and type of vocal fold polyp on some acoustic voice parameters

Background: Vocal abuse and misuse would result in vocal fold polyp. Certain features define the extent of vocal folds polyp effects on voice acoustic parameters. The present study aimed to define the effects of polyp size on acoustic voice parameters, and compare these parameters in hemorrhagic and non-hemorrhagic polyps. Methods: In the present retrospective study, 28 individuals with hemorrhagic or non-hemorrhagic polyps of the true vocal folds were recruited to investigate acoustic voice parameters of vowel/ æ/ computed by the Praat software. The data were analyzed using the SPSS software, version 17.0. According to the type and size of polyps, mean acoustic differences and correlations were analyzed by the statistical t test and Pearson correlation test, respectively; with significance level below 0.05. Results: The results indicated that jitter and the harmonics-to-noise ratio had a significant positive and negative correlation with the polyp size (P=0.01), respectively. In addition, both mentioned parameters were significantly different between the two types of the investigated polyps. Conclusion: Both the type and size of polyps have effects on acoustic voice characteristics. In the present study, a novel method to measure polyp size was introduced. Further confirmation of this method as a tool to compare polyp sizes requires additional investigations. © 2018, Shiraz University of Medical Sciences. All rights reserved

Role of the internal superior laryngeal nerve in the motor responses of vocal cords and the related voice acoustic changes

Background: Repeated efforts by researchers to impose voice changes by laryngeal surface electrical stimulation (SES) have come to no avail. This present pre-experimental study employed a novel method for SES application so as to evoke the motor potential of the internal superior laryngeal nerve (ISLN) and create voice changes. Methods: Thirty-two normal individuals (22 females and 10 males) participated in this study. The subjects were selected from the students of Iran University of Medical Sciences in 2014. Two monopolar active electrodes were placed on the thyrohyoid space at the location of the ISLN entrance to the larynx and 1 dispersive electrode was positioned on the back of the neck. A current with special programmed parameters was applied to stimulate the ISLN via the active electrodes and simultaneously the resultant acoustic changes were evaluated. All the means of the acoustic parameters during SES and rest periods were compared using the paired t-test. Results: The findings indicated significant changes (P=0.00) in most of the acoustic parameters during SES presentation compared to them at rest. The mean of fundamental frequency standard deviation (SD F0) at rest was 1.54 (SD=0.55) versus 4.15 (SD=3.00) for the SES period. The other investigated parameters comprised fundamental frequency (F0), minimum F0, jitter, shimmer, harmonic-to-noise ratio (HNR), mean intensity, and minimum intensity. Conclusion: These findings demonstrated significant changes in most of the important acoustic features, suggesting that the stimulation of the ISLN via SES could induce motor changes in the vocal folds. The clinical applicability of the method utilized in the current study in patients with vocal fold paralysis requires further research. © 2016, Shiraz University of Medical Sciences. All rights reserved

Local discriminant wavelet packet basis for voice pathology classification

Diagnosis of pathological voice is one of the most important issues in biomedical applications of speech technology. There are some approaches for separating pathological from normal voice signals but a few ones are sophisticated to separate two or more kinds of speech pathologies from each other. This paper introduces an algorithm to discriminate voice pathologies signals from each other via adaptive growth of wavelet packet tree, based on the criterion of local discriminant bases (LDB). Moreover, genetic algorithm is employed for selecting the best feature set and Support Vector Machines as classifier to obtain as much as possible better results. To evaluate the proposed approach, we apply our algorithm to separate polyp from some other pathologies like keratosis leukoplakia, adductor spasmodic dysphonia and etc. Experimental results show the superior performance of this combinational approach against its incomplete versions, i.e. in the case of separating polyp and nodule, the proposed approach leads to 85% performance against 80% for where only complete wavelet packet features without applying GA algorithm are use

Prevalence of Voice Disorders and Associated Risk Factors in Teachers and Nonteachers in Iran

Objectives Teachers are at increased risk for development of voice disorders. Because there is no published study on Iranian teachers, the aim of this study was to compare the prevalence of voice disorders among teachers and nonteachers in Iran and define the causing risk factors. Methods In the present study, 104 teachers and 41 nonteacher participants, whose jobs did not involve vocal effort, completed a questionnaire regarding to vocal complaint and four relevant risk factors. Results According to our gained data, 54.6 of teachers experienced vocal complaints during their work, although this value was 21.1 for the nonteacher group (P < 0.001). Moreover, investigating the prevalence of voice disorders during other periods of life was performed. Analyzing the questionnaire data indicated a significant higher vocal load risk factor for teachers (70.77; standard deviation SD, 29.48), in comparison with their nonteacher counterparts (27.44%; SD, 37.83; P < 0.001). In addition, our study revealed the significance of vocal load, as well as physical and environmental risk factors in the development of voice disorders in teachers with voice complaints. Conclusions Present findings indicated a higher epidemiology of voice problems among teachers in comparison with nonteacher individuals and introduced vocal load as the most important risk factor in development of voice disorder in Iranian teachers. Accordingly, it is recommended to pay special attention to negative effects of vocal load, although environmental and physical factors are also of importance. © 2016 The Voice Foundatio