Systematic review of the treatment of functional dysphonia and prevention of voice disorders.

OBJECTIVE: To evaluate the effectiveness of interventions for treating functional dysphonia or preventing voice disorders in adults. DATA SOURCES: We searched MEDLINE (1950 to 2006), EMBASE (1974 to 2006), CENTRAL (Issue 2 2006), CINAHL (1983 to 2006), PsychINFO (1967 to 2006), Science Citation Index (1986 to 2006), and the Occupational Health databases OSH-ROM (February 2006). REVIEW METHODS: Systematic review and meta-analysis of randomized controlled trials. Included studies evaluated the effectiveness of interventions for 1) treating functional/nonorganic dysphonia or 2) preventing voice disorders. We identified six randomized controlled trials about treatment and two about prevention. Two authors independently extracted data and assessed trial quality. RESULTS: A combination of direct and indirect voice therapy, compared with no intervention, improves self-reported (standardized mean difference -1.07; 95% CI -1.94 to -0.19), observer-rated (weighted mean difference [WMD] -13.00; 95% CI -17.92 to -8.08), and instrumentally assessed vocal functioning (WMD -1.20; 95% CI -2.37 to -0.03) in adults with functional dysphonia. Effects are reported to remain for at least 14 weeks. Effects are similar in patients and in teachers and student teachers screened for voice problems. We found two studies that did not show voice training, compared with no intervention, to have a preventive effective in improving self-reported vocal functioning. Assessment of publication bias showed that the real effect sizes are probably smaller. CONCLUSION: Comprehensive voice therapy is effective in improving vocal performance in adults with functional dysphonia. There is no evidence of effectiveness of voice training in preventing voice disorders.

Changes in objective acoustic measurements and subjective voice complaints in call center customer-service advisors during one working day.

SUMMARY: The aim of this study was to investigate how different acoustic parameters, extracted both from speech pressure waveforms and glottal flows, can be used in measuring vocal loading in modern working environments and how these parameters reflect the possible changes in the vocal function during a working day. In addition, correlations between objective acoustic parameters and subjective voice symptoms were addressed. The subjects were 24 female and 8 male customer-service advisors, who mainly use telephone during their working hours. Speech samples were recorded from continuous speech four times during a working day and voice symptom questionnaires were completed simultaneously. Among the various objective parameters, only F0 resulted in a statistically significant increase for both genders. No correlations between the changes in objective and subjective parameters appeared. However, the results encourage researchers within the field of occupational voice use to apply versatile measurement techniques in studying occupational voice loading.

Comparison of two inverse filtering methods in parameterization of the glottal closing phase characteristics in different phonation types.

SUMMARY: Inverse filtering (IF) is a common method used to estimate the source of voiced speech, the glottal flow. This investigation aims to compare two IF methods: one manual and the other semiautomatic. Glottal flows were estimated from speech pressure waveforms of six female and seven male subjects producing sustained vole /a/ in breathy, normal, and pressed phonation. The closing phase characteristics of the glottal pulse were parameterized using two time-based parameters: the closing quotient (C1Q) and the normalized amplitude quotient (NAQ). The information given by these two parameters indicates a strong correlation between the two IF methods. The results are encouraging in showing that the parameterization of the voice source in different speech sounds can be performed independently of the technique used for inverse filtering.

Occupational voice complaints and objective acoustic measurements-do they correlate?

To enable the development of appropriate diagnostics and treatment for occupational voice disorders, this study addresses connections between subjective voice complaints and objective observations. The subjects of this study were 24 female customer advisors, who mainly use the telephone during their working hours. During one working day, at four different times, speech samples covering 20 minutes of telephone conversation by the customer service advisors (CSAs) were recorded. In addition, the CSAs filled in a questionnaire (visual analogue scale) concerning their voice problems. To represent the vocal symptoms three variables were used: vocal fatigue, hoarseness and a general sum-variable. A 5-minute sample was taken from recordings for further analyses. This included fundamental frequency, sound pressure level, alpha ratio (the ratio between the spectral energy below and above 1000 Hz) and number of vocal fold vibrations. In the objective acoustic measurements, it was found that fundamental frequency (F0) rose significantly during the working day. Also the self-reported voice symptoms increased significantly during the working day. However, correlations between vocal symptoms and acoustic measures were not found.

Voice symptoms of call-centre customer service advisers experienced during a work-day and effects of a short vocal training course.

Occupational voice users often suffer from voice symptoms to varying extents. The first goal of this study was to find out how telephone customer service advisers experience voice symptoms at different moments of the working day. The second goal was to investigate the effects of a short vocal training course arranged for telephone workers. The results indicate that although the subjects did not suffer from severe voice problems, the short vocal training course significantly reduced some of the vocal symptoms they had experienced. The results suggest that systematic consultation and training for occupational voice users in the field of occupational voice care would be advantageous.

Automatic pre-segmentation of running speech improves the robustness of several acoustic voice measures.

In order to study vocal loading, we developed a speech analysis environment for continuous speech. The objective was to build a robust system capable of handling large amounts of data while minimizing the amount of user-intervention required. The current version of the system can analyze up to five-minute recordings of speech at a time. Through a semiautomatic process it will classify a speech signal into segments of silence, voiced speech and unvoiced speech. Parameters extracted from the input signal include fundamental frequency, sound pressure level, alpha-ratio and speech segment information such as the ratio of speech to silence. This paper presents results from the performance evaluation of the system, which shows that the analysis environment is able to perform robust and consistent measurements of continuous speech.

Longstanding recurrent laryngeal papillomatosis: impact on voice quality.

Human papilloma virus (HPV) infection in the larynx often requires frequent surgical procedures in order to keep voice quality reasonable. The purpose of this study was to evaluate the speaking voice quality of patients with longstanding recurrent laryngeal papillomatosis (RLP). The patients were seven males with adult-onset RLP whose disease had lasted over 5 years, and who were free of papilloma at the time of examination. Each patient had an age- and gender-matched control with similar smoking habits. Voice samples were recorded and acoustic analysis as well as perceptual listening test were performed. In our series a perceptual test discriminates between normal and pathological voice quality more precisely than acoustical voice analysis. It appears that the voice of the papilloma patient, even after frequent phonosurgical operations, is not deviant from the normal when analyzed acoustically, but perceptual assessment shows that overall quality is less than optimal, and roughness and breathiness are increased.

Experiences of a short vocal training course for call-centre customer service advisors.

It is commonly known that occupational voice users suffer from voice symptoms to varying extents. The purpose of this study was to find out the effects of a short (2-day) vocal training course on professional speakers' voice. The subjects were 38 female and 10 male customer advisors, who mainly use the telephone during their working hours at a call centre. The findings showed that although the subjects did not suffer from severe voice problems, they reported that the short vocal training course had an effect of some of the vocal symptoms they had experienced. More than 50% of the females and males reported a decrease in the feeling of mucus and the consequent need to clear the throat, and diminished worsening of their voice. Over 60% thought that voice training had improved their vocal habits and none reported a negative influence of the course on their voice. Females also reported a reduction of vocal fatigue. The subjects were further asked to respond to 23 statements on how they experienced the voice training in general. The statements 'I learned things that I didn't know about the use of voice in general' and 'I got useful and important knowledge concerning my work' were highly assessed by both females and males. The results suggest that even a short vocal training course might affect positively the self-reported well-being of persons working in a vocally loading occupation. However, to find out the long-term effects of a short training course, a follow-up study would need to be carried out.

Intervenciones para el tratamiento de la disfonía funcional en adultos / Interventions for treating functional dysphonia in adults

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