Association between occupational voice use and occurrence of voice disorders: a meta-analysis

Purpose: This meta-analysis has two aims: 1) to provide a quantitative assessment of the occurrence of voice disorders among different occupational voice users, 2) and to determine whether being an occupational voice user (teacher, broadcaster, call-center worker, etc.) is associated with an increased occurrence of voice disorders. Method: A random-effect meta-analysis of the available scientific literature was conducted on the occurrence of voice disorders among occupational voice users. Comprehensive literature searches were conducted using two computerized databases: PubMed/MEDLINE, and Scielo. As a measure of association, the odds ratio (OR) with corresponding 95% confidence interval (95% CI) was used. Heterogeneity was assessed by chi-square and I2 and draw in forest plots. Results: Voice disorders are related with occupational voice use independently of type of prevalence with a pool OR of 2.39 for current voice disorders, 1.88 for 12-months prevalence, and 2.43 for life-time and unspecified recall period. Heterogeneity test (I2) among these articles is 68% for current voice disorders, 0% for 12-months voice disorders, and 66% for life-time and unspecified recall period. Although around 70% of the total number of included publications assessed the occurrence of voice disorders among teachers as occupational voice users, an analysis per occupation was performed to identify possible influence of this factor in the occurrence of voice disorders. Studies that include just teachers as the group of occupational voice users (n=12) reported ORs ranging from 1.20 to 4.61. Heterogeneity test (I2) among these articles is 17%. Studies that include telemarketers, newsreaders, and sellers as the group of occupational voice users (n=6) reported ORs ranging from 0.85 when future vocal professionals were compared future non-vocal professionals to 4.58 when newsreaders were compared with non-newsreaders. Heterogeneity test (I2) among these articles is 40%. Conclusion: Occupational voice users have a higher likelihood of having voice disorders. Results of this meta-analysis show that teachers had a slightly lower likelihood (pool OR=1.95) than telemarketers, broadcasters, and sellers (pool OR=2.75) for having a voice disorder regardless the type of prevalence. Nevertheless, due the weak to moderate quality of the included studies, the results should be taken with caution.

Akustičke značajke vokalnoga zamora

Vocal fatigue is characterized by self-perceived increased laryngeal strain and voice quality changes. The condition can have organic or/and functional causes. Typically, it affects vocal professionals, and teachers are most numerous among them. Despite great number of studies, many questions about vocal fatigue such as its acoustic characterstics are still open. The hypothesis of the present study conducted on female teachers was that there are significant differences in acoustic variables between vocally fatigued teachers (N=23) and teachers without it (N=27). Running speech and prolonged phonation of the vowel /a/ were analyzed in PRAAT software calculating the long-term average speech spectrum LTASS and harmonic spectrum. The average speech F0 and series of spectral variables were calculated: the strength of the strongest spectral peak L0, the α ratio of the level difference above and bellow 1 kHz for the 0-5 kHz range analyzed, and the variables Δ1, Δ2, Δ3 and Δ4 showing the ratios of the respective spectral energy bands of 1-2 kHz, 2-3 kHz, 3-4 kHz and 4-5 kHz relative to the 0-1 kHz reference. The average H1/H2 ratio based on harmonic spectrum of three samples of the prolonged vowel /a/ production was calculated as well. The hypothesis was tested by multivariate and univariate analyzes of variance and discriminant analysis. The results showed that there are no significant differences in the set of acoustic variables between the two teacher groups, thus the hypothesis was rejected. However, the average speech F0 showed to be strong single discriminator. Its mean value in the group of teachers with vocal fatigue, that is 176 Hz, suggests dysfunction. Several factors may explain the absence of acoustic differences between the two groups, one of the most compelling of which is the fact that both groups reported similar numbers of subjective vocal and physical complaints. The results confirm the complex phenomenology of vocal fatigue syndrome, and suggest that acoustic analysis may have limited power to detect it.

Voice Disorders in Occupations with Vocal Load in Slovenia / Glasovne Težave V Poklicih Z Glasovno Obremenitvijo V Sloveniji

Aim. The aim of this paper is to compare the prevalence of voice disorders and the risk factors for them in different occupations with a vocal load in Slovenia. Methods. A meta-analysis of six different Slovenian studies involving teachers, physicians, salespeople, catholic priests, nurses and speech-and-language therapists (SLTs) was performed. In all six studies, similar questions about the prevalence of voice disorders and the causes for them were included. Results. The comparison of the six studies showed that more than 82% of the 2347 included subjects had voice problems at some time during their career. The teachers were the most affected by voice problems. The prevalent cause of voice problems was the vocal load in teachers and salespeople and respiratory-tract infections in all the other occupational groups. When the occupational groups were compared, it was stated that the teachers had more voice problems and showed less care for their voices than the priests. The physicians had more voice problems and showed better consideration of vocal hygiene rules than the SLTs. The majority of all the included subjects did not receive instructions about voice care during education. Conclusions. In order to decrease the prevalence of voice disorders in vocal professionals, a screening program is recommended before the beginning of their studies. Regular courses on voice care and proper vocal technique should be obligatory for all professional voice users during their career. The inclusion of dysphonia in the list of occupational diseases should be considered in Slovenia as it is in some European countries.

Vocal therapy of hyperkinetic dysphonia

Introduction. Hyperkinetic (hyperfunctional) dysphonia is a common pathology. The disorder is often found in vocal professionals faced with high vocal requirements. Objective. The objective of this study was to evaluate the effects of vocal therapy on voice condition characterized by hyperkinetic dysphonia with prenodular lesions and soft nodules. Methods. The study included 100 adult patients and 27 children aged 4-16 years with prenodular lesions and soft nodules. A subjective acoustic analysis using the GIRBAS scale was performed prior to and after vocal therapy. Twenty adult patients and 10 children underwent objective acoustic analysis including several acoustic parameters. Pathological vocal qualities (hoarse, harsh and breathy voice) were also obtained by computer analysis. Results. The subjective acoustic analysis revealed a significant (p<0.01) reduction in all dysphonia parameters after vocal treatment in adults and children. After treatment, all levels of dysphonia were lowered in 85% (85/100) of adult patients and 29% (29/100) had a normal voice. Before vocal therapy 9 children had severe, 13 had moderate and 8 slight dysphonia. After vocal therapy only 1 child had severe dysphonia, 7 had moderate, 10 had slight levels of dysphonia and 9 were without voice disorder. The objective acoustic analysis in adults revealed a significant improvement (p?0.025) in all dysphonia parameters except SD F0 and jitter %. In children, the acoustic parameters SD F0, jitter % and NNE (normal noise energy) were significantly improved (p=0.003-0.03). Pathological voice qualities were also improved in adults and children (p<0.05). Conclusion. Vocal therapy effectively improves the voice in hyperkinetic dysphonia with prenodular lesions and soft nodules in both adults and children, affecting diverse acoustic parameters.

Perioperative Voice Recovery and the Vocal Folds: Perspectives From the Voice Care Team

Information regarding the significance of wound healing in laryngology is steadily increasing. Vocal fold tissue may be injured by phonotrauma (excessive impact from the opposing vocal fold), chemical agents (e.g., stomach acid), trauma, or iatrogenic causes (i.e., intubation, vocal fold surgery). Following injury, the affected area becomes inflamed. The body initiates cell proliferation and matrix deposition to begin the process of healing. Matrix remodeling during the healing process determines the degree of scar formation. Vocal fold scar has well-documented structural and functional consequences, and is notoriously difficult to manage (Hirano, 2005). Our roles as vocal professionals in relationship to the stages of wound healing change at key time points: before creating a wound, when making a wound, acute management (0–2 weeks), subacute management (2–8 weeks), and late management (8 weeks and beyond)..

Risk factors for the appearance of minimal pathologic lesions on vocal folds in vocal professionals

Background/Aim. An excessive use or misuse of voice by vocal professionals may result in symptoms such are husky voice, hoarse voice, total loss of voice, or even organic changes taking place on vocal folds - minimal pathological lesions - MAPLs. The purpose of this study was to identify the type of MAPLs which affects vocal professionals, as well as to identify the risk factors that bring about these changes. Methods. There were 94 vocal professionals who were examined altogether, out of whom 46 were affected by MAPLs, whereas 48 of them were diagnosed with no MAPLs, so that they served as the control group. All these patients were clinically examined (anamnesis, clinical examination, bacteoriological examination of nose and pharynx, radiography of paranasal cavities, allergological processing, phoniatric examination, endo-video-stroboscopic examination, as well as gastroenterologic examination, and finally endocrinological and pulmological analyses). Results. The changes that occurred most often were identified as nodules (50%; n = 23/46) and polyps (24%; n = 11/46). Risk factors causing MAPLs in vocal professionals were as follows: age, which reduced the risk by 23.9% [OR 0.861 (0.786-0.942)] whereas the years of career increase the risk [OR 1.114 (1.000-1.241)], as well as the presence of a chronic respiratory disease [OR 7.310 (1.712- 31.218)], and the presence of gastro-oesophageal reflux disease [OR 4.542 (1.263-16.334)]. The following factors did not contribute to development of MAPLs in vocal professionals: sex, a place of residence, irritation, smoking, endocrinologic disease and the presence of poly-sinusitis. Conclusion. It is necessary to introduce comprehensive procedures for prevention of MAPLs, particularly in high-risk groups. Identification of the risk factors for MAPLs and prevention of their influence on vocal professionals (given that their income depends on their vocal ability) is of the highest importance.