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 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 30  |  Issue : 3  |  Page : 272-278

Dysphonia in teachers: is it only a matter of voice misuse?


1 Phoniatrics Department, Phoniatric Unit, Kasr Al-Aini Hospital, Cairo University, Ismailia governerate, Cairo, Egypt
2 Department of ENT, Suez Canal University, Ismailia Governorate, Egypt
3 Department of Phoniatrics, Suez Canal University, Ismailia Governorate, Egypt

Date of Submission26-Oct-2013
Date of Acceptance17-Feb-2014
Date of Web Publication12-Aug-2014

Correspondence Address:
Asmaa Ahmed Abdel Hamid
5th Bakry Street, Haram, Giza
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1012-5574.138494

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  Abstract 

Background
Teaching is considered among the most demanding tasks for voice;
Aim
This study investigated dysphonia in a sample of Egyptian teachers and determined the prevalence of dysphonia in the sample under study.
Patients and methods
The study was carried out by applying a questionnaire to 250 primary school teachers in Fayed city. The questionnaire included three main groups of questions that indicate the presence or absence of dysphonia, gastric reflux, and allergy, in addition to questions about personal and teaching data. The participants who reported that they suffer from dysphonia were transmitted to the second step of the study, which is acoustic analysis for their voices and laryngoscopic examination for their larynges.
Results
The present study revealed that the prevalence of dysphonia in the study sample is 23.2%. The dysphonia was based on the participants self-impression and was emphasized by the acoustic analysis; in addition, this study showed a significant correlation between dysphonia and both allergy and reflux.
Conclusion
The study revealed that prevalence of dysphonia in the sample under study which contains primary school teachers is 23.2%. A positive correlation between teaching hours/week, allergy and reflux with dysphonia with presence of pathological lesions and subclinical finding detected by acoustic analysis changes.

Keywords: acoustic analysis, dysphonia, gastric reflux


How to cite this article:
Abdel Hamid AA, Eldessouky HM, Iskender NM, Hassan EM. Dysphonia in teachers: is it only a matter of voice misuse?. Egypt J Otolaryngol 2014;30:272-8

How to cite this URL:
Abdel Hamid AA, Eldessouky HM, Iskender NM, Hassan EM. Dysphonia in teachers: is it only a matter of voice misuse?. Egypt J Otolaryngol [serial online] 2014 [cited 2019 Nov 22];30:272-8. Available from: http://www.ejo.eg.net/text.asp?2014/30/3/272/138494


  Introduction Top


Voice serves an important function of regulating social communication and interactions [1]. Dysphonia is expressed as any difficulty or change in voice emission that interferes with natural voice [2].

There has been growing interest during recent years in studying the relationship between dysphonia and teaching work. Prior research indicates that teachers represent a high-risk group with respect to the development of voice problems [3].

The vocal loading that occurs in the daily life of teachers has several causes; long teaching hours, poor room acoustics, and bad air quality are seen as the leading causes of voice problems in teachers. Psychological and emotional aspects may also contribute to voice disorders [4,5].

Allergies may cause excessive mucous and edema of the vocal folds; edema and excessive mucous on the vocal folds have a negative effect on the voice quality [6]. In addition, it causes an increased need for throat clearing and coughing [7]. Similarly, Issing et al. [8] has evaluated and reported negative effects of pathological acid reflux on the mucosa of the larynx.


  Aim Top


The aim of this study was to answer the study question whether dysphonia in teachers is due to voice misuse only or there are other underlying factors and to determine the prevalence of dysphonia in the study sample and laryngeal pathology underlying dysphonia in teachers.


  Patients and methods Top


Patients

Population of study was 250 teachers working in primary schools in Fayed Educational Management, which are governmental schools. Both male and female teachers were included. They were involved in the active teaching process and had spent in this teaching process at least 1 year. Their age ranged from 22 to 50 years (mean age 36.12 years). In addition, 30 normal age-matched and sex-matched individuals were taken as the control group for acoustic measurements.

Inclusion criteria

(1) Teachers with almost similar voice misuse during teaching hours/day (4-6 h), with a teaching period more than 1 year.

(2) The same type of schools (governmental), the same teaching stage (primary schools), and nearly the same environmental conditions.

Exclusion criteria

(1) Smokers.

(2) Teachers with known autoimmune, endocrinal disease, neurological disorders, diabetes, hypertension, or under long medical treatment.

Methods

The study was a descriptive, cross-sectional study conducted in primary school teachers in Fayed city, Ismailia governorate (Governmental Primary Schools that belong to Fayed Educational Management at Ismailia governorate). The study was performed during the period between April 2012 and May 2013.

Study sample

Sample type
: Simple random sample was selected by choosing teachers from a given list (every even number), obtained from records of directorate of upbringing and education of Ismailia, then the schools where they work were identified to reach them through school visits.

Sample size: A sample of 250 primary school teachers was included, 39 (15.6%) male teachers and 211 (84.4%) female teachers. The sample size was obtained through the following statistical equation:

SS = (Z0α/2/E) 2 × P (1-P)

where Zα/2 is 1.96 for 95% confidence level, P is the prevalence of dysphonia (28.8%), and E = SE × P × Zα/2 [standard error (SE) = 0.1].

Data collection

Data were collected through the following:

(1) Protocol of voice assessment applied in Kasr Al-Aini Hospital was carried out for those participants who reported that they are dysphonic by the applied questionnaire. It included:

(a) Elementary diagnostic procedures:

(1) Patient interview and thorough personal history taking, including age, sex, occupation, highlighting the duration of teaching experience in years and number of teaching hours/week.

(2) Searching for etiological factors: abuse and misuse of voice, exposure to dust and fumes, allergy, reflux, medications, recurrent respiratory tract infection, and previous surgeries.

(3) Complaint and analysis of symptoms by asking about the duration, onset, and course and by asking about phonathenic symptoms, which include throat dryness, soreness, tenderness, frequent throat clearing, difficulty in swallowing, and sticky throat mucous.

(4) Searching for etiological factors: abuse and misuse of voice, dust, fumes, allergy, reflux, medications, recurrent respiratory tract infection, and previous surgeries.

(b) Use of questionnaire: These are questions related to allergic rhinitis symptoms that have been identified in the peer-reviewed literature as having the greatest diagnostic value. It will not produce a definitive diagnosis, but they are highly suggestive of allergic rhinitis [9]. Questions that indicate presence or absence of gastric reflux were obtained from the reflux symptom index (RSI) by Belafsky et al. [10] who consider an RSI greater than 13 to be abnormal. Hence, in the present study, the teacher is considered positive for reflux when he or she has a RSI score greater than 13.

(c) Auditory perceptual assessment (APA) was performed by two phoniatricians using the 'modified GRBAS scale' [11] as following:

Dysphonia: overall grade, character (strained, leaky, breathy, or rough), pitch (overall increase, overall decreased, or diplophonia), register (habitual register, register break, or tendency of vocal fry at the end of phrases), loudness (excessively loud, excessively soft, or fluctuating), glottal attack (normal, hard, or soft), associated laryngeal functions (cough, whisper, and laughter, which may be affected).



The APA was documented by voice recording, which was carried out in a sound-treated room with a high fidelity computerized audio recording system.

(2) Clinical diagnostic aids:

A laryngeal videoendoscopy was carried out using 90° rigid endoscope of a Karl Storz endoscopic set (Germany). It was performed for dysphonic participants to find out why are they dysphonic.

(3) Additional instrumental measures:

Acoustic analysis: the acoustic analysis was performed using the voice analysis software Praat version 5.3.40 (Paul Boersma and David Weenink, The University of Amsterdam, The Netherlands) [12]. [Praat (the Dutch word for 'talk') is a scientific computer software package] after optimizing it for voice analysis. Jitter (%), shimmer (dB), and harmonic-to-noise ratio were obtained.

Data management and statistical analysis

The collected data were revised, summarized, and then analyzed by statistical package for the social science (SPSS, version 16; SPSS Inc., Chicago, Illinois, USA).

Data were calculated and presented with corresponding 95% confidence intervals. Parametric data were expressed as mean ± SD and nonparametric data were expressed as number and percentage of the total. The analyzed data were then presented into tables and graphs.

Ethical considerations

Our study was ethically approved by obtaining the agreement of the following:

(1) Postgraduate and ENT Department.

(2) Ministry of Upbringing and Education.

(3) Central Agency for Public Mobilisation and Statistics of Arab Republic of Egypt.

(4) Directorate of Upbringing and Education of Ismailia.

(5) Management of Upbringing and Education of Fayed.

(6) Managers and teachers of the schools studied.


  Results Top


Data of this study were analyzed statistically and they show the following results:

(1) Data of the participants included age, sex [Figure 1], teaching years, and teaching hours [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7].

(2) Dysphonia distribution and its relationship with age and sex [Table 8], [Table 9], [Table 10].
Figure 1: Sex distribution among subjects

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(3) Allergy distribution and its correlation with dysphonia [Table 11] and [Table 12].

(4) Reflux distribution and its correlation with dysphonia [Table 13] and [Table 14].
Table 1 Statistical description of age of participants

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Table 2 Statistical description of teaching years among participants

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Table 3 Comparison of mean and SD of teaching years between male and female teachers

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Table 4 Statistical description of teaching hours/week among participants

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Table 5 Comparison of teaching hours/week between male and female participants

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Table 6 Comparison of teaching hours/week between dysphonic and nondysphonic participants

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Table 7 Comparison of teaching years between dysphonic and nondysphonic participants

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Table 8 Distribution of dysphonia (according to selfimpression of participants)

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Table 9 Correlation between dysphonia and sex

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Table 10 Comparison of age between the dysphonic and nondysphonic groups

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Table 11 Distribution of allergy (according to self-impression of participants)

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Table 12 Correlation between dysphonia and allergy

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Table 13 Distribution of refl ux (according to self-impression of participants)

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Table 14 Correlation between dysphonia and refl ux

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(5) Videoendoscopic results of dysphonic participants: distribution and types of vocal fold pathology among examined participants [Table 15] and [Table 16] and [Figure 2], [Figure 2], [Figure 3], [Figure 4], [Figure 5].
Table 15 Distribution of vocal fold pathology among examined participants

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Table 16 Description of the pathological lesions

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Figure 2: Vocal fold nodules

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Figure 3: Vocal fold polyp

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Figure 4: Vocal fold hemorrahge

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Figure 5: Phonatory gap

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(6) Comparison between acoustic analysis results of the control and dysphonic groups [Table 17].
Table 17 Comparison between the jitter, shimmer, and harmonic-to-noise ratio () of the control and dysphonic group

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  Discussion Top


Voice function is a complex phenomenon and has an undisputable relationship with the voice load and occupational demands [13].

In this study, there were 250 teachers in total, consisting of 84.4% female teachers and 15.6% male teachers [Figure 1], which is in agreement with the study by Laukkanen and colleagues who stated that female teachers are a majority in the teaching profession.

This study shows that the prevalence of dysphonia in the sample under study - according to self-subjective impression of teachers - is 23.2%, which is a relatively high prevalence [Table 8]. The reason is because teachers often spend a long time talking loudly in noisy environments and in stressful situations [14]. In addition, there is a general agreement that vocal load is the major cause of voice problems in the teaching staff [2].

Different studies conducted have shown that the prevalence of voice fatigue in teachers varies from 18 to 32% [3, 15, 16]. The prevalence of dysphonia is quiet close to that of the present study.

The prevalence in other studies ranges from 50 to 88% [17]. This is so far much higher than that of the present study. Varying results in these papers may be explained by differences in defining duration of the condition, frequency of symptoms, and differences in sample size.

APA of teachers with complaint of dysphonia revealed variable degrees of dysphonia. Acoustic analysis confirmed APA finding by abnormal jitter, shimmer, and mean harmonic-to-noise ratio values as compared with the control group [Table 17].

Videolaryngoscopic examination was performed in those participants who consider themselves to be dysphonic - by questionnaire - to find out why are they dysphonic. It shows that 86.2% of dysphonic patients show pathological lesions in their vocal folds, whereas 13.8% of them show free vocal folds [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6] and [Table 16].
Figure 6: Arytenoid edema and vocal fold erythema

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The presence of acoustic analysis changes even without the presence of structural pathology could be explained by that dysphonia in the absence of laryngeal structural pathology may precede laryngeal structural pathology [18]. In addition, what may seem to be functional dysphonia on evaluation has been suggested by some studies to possibly be secondary to microorganic disease instead (organic disease not detectable on examination) [19].

The explanation for this dysphonia is because teachers often spend a long time talking loudly in noisy environments and in stressful situations [14]. These talking styles lead to increased glottal closure, which elevate vocal fold impact stress resulting in functional voice problems and vocal fold pathologies, especially vocal fold nodules [20].

These are the same reasons for Tavares and Martins [21], who stated that vocal overuse or misuse during teaching over a period of time is a primary cause of voice disorders and vocal fold pathologies. This result is in concordance with another study, which showed that teachers are more susceptible to aphonia, edema, polyps, and nodules than nonvocal professionals [22].

This study revealed that teaching years has no relationship with the development of dysphonia [Table 7]. This could be explained by that younger teachers reported greater vocal difficulties due to working longer hours and having poorer vocal hygiene techniques than their older, more experienced peers [23]. This result agree with the study conducted by Simberg et al. [24], who reported that length of teaching experience has little correlation with the frequency of voice disorders. In addition, other studies reported that old age is not a risk factor for dysphonia [22]. However, this result disagrees with studies showing that one of the risk factors for the development of dysphonia is being older or having more years of teaching experience [3,25].

This study revealed that there is a positive correlation between teaching hours/week and presence or absence of dysphonia [Table 6]. This could be because of cumulative voice use [16]. As the vocal loading that occurs in the daily life of teachers has several causes, one of them is long teaching hours [4].

Concerning sex, this study revealed that there is no correlation between sex and development of dysphonia, which is unexpected [Table 9], as women have some physiological factors that predispose them to the development of voice problems, such as a glottic configuration favoring bowing, hormonal influence on vocal qualities, and higher incidence of endocrinological diseases; in addition, women have shorter vocal folds and produce voice at a higher fundamental frequency. In addition, there is less tissue mass to dampen a larger amount of vibrations and lower levels of hyaluronic acid in the superficial layers of lamina propria, which decreases the tissue viscosity of the vocal folds and their shock-absorbing capabilities [21]. This result may be due to difference between male and female teachers included in this study with respect to number of teaching hours/week and number of teaching years.

This result disagrees with the study conducted by Smith et al. [22], who reported female sex as one of the risk factors for dysphonia, in addition to the study conducted by Laukkanen et al. [26], who revealed that female individuals have about twice as many voice problems as male individuals.

It also disagrees with previous studies that have been consistently reporting that female teachers have significantly more voice problems than their male colleagues [17,27].

With respect to allergy, this study shows that there is a positive correlation between allergy and dysphonia [Table 12]. It can be explained by that the mucous is heavier and more tenacious in allergic persons than in persons without allergy and interferes with the mucosal wave in the vocal folds [28]. This result agrees with the results of a survey by Roy et al. [3], who showed that the patients who had voice disorders reported respiratory allergies significantly more often than those who did not have voice disorders. In addition, the results of two questionnaire studies showed that allergic patients have more frequently occurring vocal symptoms than patients in the control group [24,29]. However, this disagrees with the study by King et al. [6], who reported that the larynx of allergic patients is often normal.

This study showed that reflux also has positive correlation with dysphonia [Table 14]. This table shows that 60.3% of dysphonic patients are positive for reflux. The explanation is that the delicate ciliated respiratory epithelium of the posterior larynx that normally functions to clear mucus from the tracheobronchial tree is altered by the gastric refluxate, and the resultant ciliary dysfunction causes mucus stasis. The subsequent accumulation of mucus produces postnasal drip sensation and provokes throat clearing [30].

In addition, the direct refluxate irritation can cause coughing and choking (laryngospasm) because of sensitivity inflammation [30]. This combination of factors can lead to vocal fold edema, contact ulcers, and granulomas that cause laryngopharyngeal reflux (LPR)-associated symptoms such as sore throat, globus pharyngeus, and dysphonia [31].

This result agrees with the results of Ross et al. [32] who reported that all patients with suspected LPR had significantly increased abnormal perceptual voice characteristics in the form of musculoskeletal tension, hard glottal attack, glottal fry, restricted tone placement, and dysphonia.

In addition, Pribuisiene et al. [33] had reported that parameters including jitter, shimmer, normalized noise energy, voice handicap index, and phonetogram parameters were significantly different in patients with LPR.

In contrast, different authors have shown that laryngeal findings commonly attributed to reflux laryngitis can be visualized in up to 64-86% of normal controls [34,35]. In addition, a structured review of randomized controlled trials has failed to detect a significant advantage of proton pump inhibitors over placebo in the treatment of patients with reflux laryngitis, which indirectly make the role of reflux in dysphonia questionable [36].


  Acknowledgements Top


 
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12], [Table 13], [Table 14], [Table 15], [Table 16], [Table 17]


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