Portuguese Version

Year:  2003  Vol. 69   Ed. 6 - (12º)

Artigo Original

Pages: 807 to 812

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Vocal problems in kindergarten and primary school teachers: prevalence and risk factors

Author(s): Vera L. R.Fuess1,
Maria Cecília Lorenz2

Keywords: dysphonia, professional, teacher, associated factors

Abstract:
Dysphonia is a frequent complaint among teachers, an occupation in which the voice is a fundamental tool. Objectives: This study aimed at evaluating the prevalence of dysphonia in pre- and primary school teachers, observing associate symptoms and factors, in order to delineate guidelines for future prevention programs. Study design: Transversal cohorte. Patients and method: This cross-sectional study consisted of a survey that enrolled 451 teachers of 66 primary public schools of Mogi das Cruzes. The teachers answered to a questionnaire that assessed, besides identification and demographic data, their professional activity, dysphonia characteristics, associate symptoms and habits. Thirty teachers that presented constant voice symptoms were submitted to laryngoscopy, and an objective diagnosis was firmed. Results: Dysphonia was present in 80,7% of the studied teachers. There was no significant association between the frequency of dysphonia and age, profession time, class type and the number of non-professional voice abuse factors or smoking. There was significant relation between the frequency of dysphonia and weekly work hours (p < 0,01) and number of pupils per class (p < 0,02). There was also significant association between the frequency of disfonia and the presence of allergic rhinitis (p < 0,001) and/or gastro-esophageal reflux (p < 0,01) symptoms. Conclusions: Dysphonia is a very common symptom among teachers. Prevention programs should include measures of reduction of the working time and the number of pupils per class, as well as the treatment of associate non-professional pathologies.

INTRODUCTION

Voice is a fundamental instrument in the occupational life of a teacher. As an element that should convince and influence the audience, the voice requires precise adaptation of all phonation organs; failure to do so poses the risk that it may present dysphonic symptoms, early or late, harmful to the activity of teaching (Garcia, 1986; Calas, 1989, Penteado, 1999).

Mattiske (1998) carried out a literature review to check whether teachers really form a group of occupational risk for development of dysphonia, what are the types of vocal problems that they present and what are the causes. The author observed difficulty in defining prevalence of vocal disorders in the published studies, owing to much discrepancy among the used definitions, the employed methodology and the results. Literature data showed that one in each two teachers presented vocal symptoms and complaints (Calas, 1989), and that teachers presented twice or three times more complaints than other professionals (Smith, 1998). These data reveal the importance of the problem, which we should try to address in a preventive and curative fashion. The prevention of this affection related to professional vocal use involves identification of the conditions that predispose to dysphonia development (anatomical, infectious, psychological factors) and promotion of opportunities for training in vocal techniques in addition to reduction of noise levels in the school environment and around it (Sarfati, 1987).

The noise at schools hinders good understanding of the message transmitted to students, causing modifications of vocal and psychological behavior in teachers (the mean sound level of speech increases when the environment noise exceeds 30dB SL = Lombard effect) (Sataloff, 1991; Calas, 1989).

According to Smith (19981) and Mattiske (1998), even though it is clear that the teaching activity increases the risk of vocal problems, the specific risk factors for development of dysphonia among teachers are still not defined. The interest in the topic, including the Public Health perspective, as well as lack of local data, motivated this study that aimed at analyzing the prevalence of this symptom in teachers and assessing the associated factors and symptoms so as to define prevention measures of occupational dysphonia.

MATERIAL AND METHODS

This transversal study consisted of a survey conducted by the Local Department of Education of Mogi das Cruzes* by sending questionnaires to all preschool and primary school teachers of 66 local city-owned schools. Among all eligible teachers, only 3 did not answer the questionnaire, amounting to 541 enrollments (448 female teachers and 3 male teachers, mean age of 35.0 +/- 7.0 years).
The questionnaire contained, in addition to identification and demographic data, questions about:

 Professional activity of teachers (time in the job, weekly working hours, number of students per class);
 Type of class in which they teach (preschool, primary school or special education classes);
 Performance of extra-school activities that required vocal strain (singing, small children, religious ceremonies, or any other profession related to voice use);
 Presence of other concomitant symptoms (suggestive of allergic rhinitis and gastroesophageal reflux);
 Presence of smoking.

As to dysphonia, the following data were obtained in the questionnaire:

 Categorization by teacher of constant, frequent, occasional or absent symptoms (indicating the degree of professional/social impairment of dysphonia);
 Symptoms associated (vocal fatigue and pain while speaking);
 Previous diagnoses (referred diagnosis).

All professionals that reported constant vocal problems were invited to undergo laryngeal examination with telescope Karl Storz 8702 D 90°, whose results were recorded by a microcamera Toshiba with videocassette, with all exams conducted by the author. Out of 37 summoned teachers only 30 came and received medical guidance based on the test result.

Statistical methodology included descriptive tools, as well as analysis of variance (ANOVA, used to compare means of quantitative variables) and chi-square test (to check association between categorical variables). The level of significance was 0.05, as advocated for biological trials.

Graph 1. Prevalence of dysphonia in preschool and primary school teachers (n = 451).



Graph 2. Absence of association between frequency of dysphonia and number of extra-professional factors of vocal abuse (p < 0.20).



Graph 3. Distribution of different degrees of vocal fatigue in different frequencies of dysphonia symptoms.



Graph 4. Distribution of different degrees of odynophonia in different frequencies of dysphonia symptoms.



Graph 5. Significant relation between presence of symptoms of allergic rhinitis and frequency of dysphonia (p < 0.001).



Graph 6. Distribution of frequency of dysphonia in patients with and without symptoms of gastroesophageal reflux (p < 0.01).



Graph 7. Distribution of smoking in different frequencies of dysphonia symptoms (p < 0.40).

RESULTS

Prevalence of dysphonia
Out of 451 studied teachers, 87 (19.3%) did not report episodes of dysphonia, 257 (57.0%) reported presence of occasional dysphonia, 70 (15.5%) presented frequent episodes of dysphonia, and 37 (8.2%) reported they were constantly hoarse (Graph 1).

Age, time in the job, weekly working hours and number of students per class
We did not observe statistically significant differences between mean age and time in the job comparing the groups of teachers with different frequency of dysphonia symptoms (constant, frequent, occasional and absent).

We observed statistically significant difference between the groups with distinct frequency of dysphonia concerning mean weekly working hours (P<0.01) and mean number of students per class (p < 0.02) (Table 1). As we observed, groups of teachers with constant and frequent dysphonia presented mean weekly working hours that were high and in teachers with occasional and absent dysphonia, the means were low. The same was observed concerning the mean number of students per class.

Type of class
Even though we observed a tendency of high concentration of preschool teachers among professionals with constant dysphonia, there was no statistically significant difference between type of class and frequency of dysphonia (p < 0.06) (Table 2).

Extra-professional factors of vocal abuse
We did not observe correlation between frequency of dysphonia symptoms and presence or number of extra-professional factors of vocal stress (p < 0.20) (Graph 2).

Associated symptoms

Vocal Fatigue
This symptom was present in 55.6% of the studied teachers, being that 27.7% of them had occasional fatigue and in 27.9% the symptom was constant.

We observed significant association between presence of vocal fatigue and frequency of dysphonia, with absence of symptom in teachers without dysphonia and presence of significant fatigue related to speech in teachers with frequent or constant dysphonia (Graph 3).

Pain while speaking
Odynophonia was present in 28.6% of the interviewed teachers, being occasional (20%) or constant (8.6%).
We also observed association between presence of odynophonia and frequency of dysphonia, and pain proved to be more frequent in teachers with frequent or constant dysphonia (Graph 4).

Symptoms of concomitant affections
Symptoms suggestive of allergic rhinitis were reported by 116 teachers (25.7%) and symptoms suggestive of gastroesophageal reflux were reported by 100 teachers (22.2%). Both categories of symptoms presented simultaneously in 62 teachers (13.7%).

We observed significant association between presence of symptoms of allergic rhinitis and frequency of dysphonia (p<0.001), that is, symptoms of allergic rhinitis proved to be more common in teachers with frequent or constant dysphonia (Graph 5).

We also observed association between presence of gastroesophageal reflux disease and frequency of dysphonia (p<0.01). Here also the symptoms of reflux were more commonly observed in patients with frequent or constant dysphonia (Graph 6).

Smoking
The prevalence of smoking was 8.9% among studied teachers. We did not observe association between smoking and degree of dysphonia (p<0.040) (Graph 7).

Previous diagnosis (referred in the questionnaire)
Previous diagnoses reported by the teachers with occasional, frequent or constant dysphonia (n=105) can be observed in Table 3. The allergic etiology and functional dysphonia proved to be more frequent, followed by vocal fold nodules and the diagnosis of laryngitis by pharyngolaryngeal reflux.

Laryngoscopic diagnosis in teachers with constant dysphonia
The diagnosis defined through laryngeal telescopic examination in 30 teachers with constant dysphonia who came to be tested can be observed in Table 4.

Table 1. Frequency of dysphonia and variables related to occupational activity. We detected association between frequency of dysphonia and weekly working hours (p < 0.01) and number of students per class (p < 0.02).



Table 2. The predominance of preschool teachers among those with constant dysphonia was not statistically significant (p < 0.06).



Table 3. Previous diagnosis referred by some studied teachers (n = 105).



Table 4. Laryngoscopic diagnosis of 30 teachers with constant dysphonia who came to the be examined.

DISCUSSION

The frequency of vocal complaints in studied teachers (80.7%) coincides with international literature data (Gotaas, 1993; Sapir, 1993; Urrutikoetxea, 1995; Smith, 19982).

We observed a clear predominance of women in teaching positions. The literature data suggest that women are more predisposed to dysphonia, especially when they are teachers of preschool children, owing to the reduced dimensions of the larynx and the little difference between their vocal frequency and that of children, which would force them to increase vocal intensity to be heard by children (Calas, 1989).

Sapir (1993) did not observe, differently from us, association between frequency of dysphonia and working hours of teachers. Other studies, such as the one by Urrutikoetxea (1995), did not count on teachers with different working hour schedules. Our findings concerning association between frequency of dysphonia and number of students per class found support in the literature (Sarfati, 1989). It is believed that this direct relation is due to the fact that larger classes are normally noisier, especially at preschool (Calas, 1989).

Differently from what we expected, we did not observe relation between frequency of dysphonia and age or time in the job, as Sapir did (1993). We believe that it is due to the fact that teachers with significant vocal problems are transferred to other activities rather than teaching, or some, in more extreme cases, end up quitting teaching. Urrutikoetxea (1995) stated that as time goes by, teachers grow an auto-feedback so as to develop involuntary self-control, spontaneously improving their vocal technique. It would justify the reduced incidence of vocal nodules as a result of increase in number of years in the profession.

We did not observe association between frequency of dysphonia and type of class. Literature data suggest that teachers of younger children are more prone to vocal disorders (Sarfati, 1989), however, we worked only with preschool and primary school years and we did not observe differences between them concerning frequency of dysphonic symptoms in teachers, who formed a homogenous group concerning vocal use. We observed, however, tendency of higher concentration of preschool teachers among those with constant dysphonia.

A study conducted by Calas (1989) with dysphonic teachers showed that 25% of them presented significant extra-professional vocal activity (choir, political activities, shouting at the kids, sport activities). We did not observe association between number of extra-professional activities and frequency of dysphonia, agreeing with the results presented by Urrutikoetxea (1995).

Among the studied teachers, 55.6% reported vocal fatigue of varied degree. This symptom was found in 80% of the dysphonic teachers (Gotaas, 1993) and in 31% of the population of 1,046 teachers (Urrutikoetxea, 1995), and these values, when associated with vocal occupational disorders, form the so-called Strain-Fatigue Laryngeal Syndrome. This syndrome is characterized by fluctuating vocal quality, worse after physical or emotional stress, associated with inappropriate respiratory support (Koufman, 1988).

The presence of odynophonia showed a significant relation with frequency of dysphonia. In accordance with literature data, 28.6% of the total number of teachers referred this symptom, which apparently represents a symptom from muscle-skeletal tension (Koufman, 1988).

We observed significant association between allergic rhinopathy and frequency of reported dysphonia. The allergic picture has high prevalence in this body region, which can explain the importance it has as a predisposing or aggravating factor for dysphonia in teachers. It is likely that exposure of the larynges to mucosa irritants can alter the delicate vocal mechanism, from which we can deduct the importance of assessing the environment where the teacher works to prevent aggravation of the condition owing to presence of dust or mold (Sataloff, 1991; Penteado,1999).

We also observed the association between symptoms of gastroesophageal reflux and increase in frequency of dysphonic symptoms. We believe that these data should be analyzed to indicate a possible way of preventing and treating dysphonia, which is sometimes purely professional.

The diagnosis defined by laryngeal telescopic examination revealed the occurrence of dysphonia by occupational demand in 50% of the cases (functional dysphonia, nodules), in 20% of the cases we observed congenital lesions (cyst and sulcus) in which the professional vocal use worked as a reinforcement of the underlying lesion, and in 30% of the cases we observed dysphonia of non-occupational etiology (pharyngolaryngeal reflux, laryngitis of allergic or infectious cause, and Reinke's edema). These data agree with those in the literature concerning occupational dysphonia (Garcia, 1986; Calas, 1989; Sarfati, 1989). As to congenital etiology, our figures agreed with those of previous studies (Sarfati, 1989), but they were much higher than others (Calas, 1989; Urrutikoetxea, 1995). Our findings of non-occupational etiology revealed very high prevalence of allergic and pharyngolaryngeal reflux clinical pictures.

CONCLUSION

Dysphonia proved to be high in preschool teachers and in the four first years of primary school. Our study suggested that preventive measures should contemplate the reduction of the working hours and the number of students by class, as well as the treatment of concomitant affections, in addition to having precise laryngoscopic diagnosis. The treatment of respiratory allergy and pharyngolaryngeal reflux can support the prevention and treatment of dysphonia that used to be taken as purely functional.

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1 Discipline of Otorhinolaryngology, Medical School, University of Mogi das Cruzes, SP, Brazil.
2 Clinical Otorhinolaryngology, Hospital das Clínicas, Medical School, University of Sao Paulo, SP, Brazil.
Address correspondence to: Vera Lucia Ribeiro FUESS - Rua Galdino Alves, 220 Mogi das Cruzes SP 08780-250.
Fax (55 11) 4725-9596 - E-mail: nariclin@terra.com.br
Study presented as Free Communication, 36º Congresso Brasileiro de Otorrinolaringologia, Florianópolis, SC.
* The city has 721 Km2 and counts on 330,000 inhabitants, part of an important economic center in the East region of Greater Sao Paulo.
Article submitted on December 18, 2002. Article accepted on September 11, 2003.

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