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Risk Factors and Effects of Voice Problems for Teachers
Risk Factors and Effects of Voice Problems for Teachers *Sheng Hwa Chen, †Shu-Chiung Chiang, ‡Yuh-Mei Chung, §Li-Chun Hsiao, and kTzu-Yu Hsiao, Taipei, Taiwan Summary: The objective of this study was to investigate risk factors of voice problems for teachers with voice disorders as compared to teachers without voice disorders. Many studies have reported risk factors and effects of teachers’ voice problems from different professions. Few researchers have investigated these phenomena among people of the same occupation. The purposes of the study are (1) to investigate risk factors of voice problems for Taiwanese teachers with voice disorders as compared to teachers without voice disorders; and (2) to investigate effects of voice problems on daily life in the two groups. A prospective study was designed for this research. One hundred and seventeen questionnaires were collected from schoolteachers. The subjects were divided into a voice disorder group (VD group) and a no voice disorder group (NVD group) from questionnaires. The Chi-square test was used to examine the significant differences of VD and NVD groups in demographic characteristics, living habits, teaching characteristics, health condition, voice symptoms, physical discomfort, and daily life. Logistic regression was used to find risk factors and effects of voice problems for teachers. Subjects in the VD group were at significantly higher risk of using a loud voice in teaching than the subjects in the NVD group. Subjects in the VD group had significantly greater effects in changing overall job opinions, reduction of overall communicative ability, decreasing phone calls, reduction of overall social ability, influence on overall emotional state, and the frequency of being upset than subjects in the NVD group. These results imply the need for a preventive voice care program for teachers. Key Words: Teachers–Voice problems–Voice disorders–Questionnaires–Risk factors–Effects. INTRODUCTION Almost 300,000 schoolteachers in Taiwan use their voice as a primary tool of employment.1 Teachers are the most likely to develop voice problems of any professional group.2,3 Eleven to 89% of teachers have been reportedly experienced a variety of vocal symptoms such as vocal fatigue, dysphonia, increased phonation effort, dry throat, tightness, sore throat, etc.4–12 This is due to the fact that teachers often spend long periods of time talking loudly in noisy environments and in stressful situations.7,10,13–15 Also, they are reported to speak with increased vocal effort and incorrect phonation techniques, and often show a psychological predisposition to voice disorders.4,10–12 These factors lead to vocal fatigue and eventually vocal fold tissue damage.4,10,16 Voice problems have adverse effects on teaching activities, teaching performance, communicative ability, and emotion. These lead to a lesser quality of teaching and increased absenteeism.5,8,11,17 Teachers may even be forced to end their career because of vocal difficulties.5,18 Many researchers have been trying to develop prevention programs for teachers with risk factors and ones that have already experienced voice difficulties. However, these research findings were mostly based on comparisons between teachers and nonteachers.4,5,10,18–20 Only a few of them were from within teachers’ groups.11,12,17 The inherently different vocal loading Accepted for publication July 30, 2008. From the *Department of Speech and Hearing Disorders and Sciences, National Taipei College of Nursing, Taipei, Taiwan; yDepartment of Informatics, Veterans General Hospital-Taipei, Taipei, Taiwan; zDivision of Speech Pathology, Department of Rehabilitation Medicine, Veterans General Hospital-Taipei, Taipei, Taiwan; xDepartment of Otolaryngology, Tri-Service General Hospital, Taipei, Taiwan; and the kDepartment of Otolaryngology, National Taiwan University, Taipei, Taiwan. Address correspondence and reprint requests to Sheng Hwa Chen, PhD, CCC-SLP, Department of Speech and Hearing Disorders and Sciences, National Taipei College of Nursing, 7F, #31, Alley52, Lane117, Tien-Mu West Road, Peitou, Taipei 112, Taiwan. E-mail: [email protected] Journal of Voice, Vol. 24, No. 2, pp. 183-192 0892-1997/$36.00 Ó 2010 The Voice Foundation doi:10.1016/j.jvoice.2008.07.008
between teaching and nonteaching groups makes their respective voice-related problems fundamentally different. The use of this method allows us to analyze the influence of different teaching characteristics, such as years in occupation, courses taught, vocal loudness in the classroom, etc on voice problems for teachers. Also, previous studies did not seek to include the influence of demography, living habits, and health condition on voice problems for people of the same occupation. Moreover, it is difficult to determine the job-related effects of voice problems on psychosocial aspects for teachers. The objectives of the study are (1) to investigate risk factors of voice problems for teachers with voice disorders as compared to teachers without voice disorders, and (2) to investigate the effects of voice problems on daily life in the two groups. These results could help to develop preventive voice care programs in schools to reduce the frequency and severity of voice problems, the impact of voice disorders, and overall intervention cost. METHODS Subjects Five elementary, middle, and high schools in Taipei City were randomly selected for the study. All 254 teachers in these schools were given a self-reporting questionnaire. One hundred and fifty-two questionnaires were returned, of which only 117 questionnaires were correctly filled out, creating a response rate of 46%. The investigators divided the subjects into two groups based on the frequency of voice problems in the questionnaires. A four-point scale was used to rate the answer by the subjects, where ‘‘0 ¼ never,’’ ‘‘1 ¼ sometimes,’’ ‘‘2 ¼ often,’’ and ‘‘3 ¼ always.’’ Subjects whose score was equal to or higher than ‘‘2’’ in the questions were placed into a voice disorder group (VD group); the others were placed into the no voice disorder group (NVD group). The VD group consisted of 59 subjects with a mean age of 40.5 years. The
184 NVD group consisted of 58 subjects with a mean age of 42.2 years. Questionnaire The questionnaire in the study was designed based on the investigators’ clinical experiences and other reports in professional voice disorder literature (Appendix).5,8,10,18,19,21,22 The information elicited in the questionnaire was (1) demographic characteristics of gender and age, (2) living habits such as smoking, consumption of alcohol and caffeine, etc, (3) teaching characteristics such as years in occupation, grades taught, self-reported vocal loudness, etc, (4) health condition associated with voice problems such as upper respiratory infection, nasal allergy, gastrointestinal reflux, etc, (5) experience voice symptoms such as hoarseness, breathiness, tired voice, etc, (6) experience physical discomfort associated with voice problems such as dryness, strain, ache, etc, and (7) adverse effects of voice problems on daily life. Demographics, living habits, teaching characteristics, and health condition in the questionnaires may represent risk factors for voice problems of the subjects. Adverse effects of voice problems on daily life may determine functional impact of voice problems on teaching aspects, job opinions, communicative ability, social ability, and emotion. Statistical analysis The Pearson chi-square test was used to examine the significant differences of VD and NVD groups with respect to demographic characteristics, living habits, teaching characteristics, health condition, voice symptoms, physical discomfort, and daily life. Multivariate logistic regression was used to evaluate the odds ratios (ORs) and 95% confidence intervals (CIs) between VD and NVD groups, and demographic characteristics, living habits, teaching characteristics, and health condition to find risk factors for voice problems. The NVD group was considered the reference, or low risk group, compared to the VD group. Univariate logistic regression was used to evaluate the effects of voice problems between teaching style, job opinions, communicative ability, social ability, and emotion, and VD and NVD groups. The negative findings in teaching style, job opinions, communicative ability, and emotion are considered the reference group, compared to the positive findings of these variables. All calculations were conducted using the SPSS 12.0 (SPSS Inc., Chicago, IL). RESULTS Demographic characteristics and living habits More females than males participated in the study, of which 98 were females and 19 were males. Demography, living habits, and chi-square test of the VD and NVD groups are reported in Table 1. Although no significant difference was found in age groups between VD and NVD, the subjects in the 20–29year range had a higher rate of being in the NVD group than the VD group. VD and NVD groups had approximately equal numbers of subjects in alcohol and caffeine consumption, and number of vices. However, the VD group had significantly more subjects taking medicine than the NVD group (c2 (1) ¼ 9.01, P ¼ 0.001).
Journal of Voice, Vol. 24, No. 2, 2010
TABLE 1. Demography and Living Habits of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups VD (n ¼ 59)
Age (yr) 20–29 30–39 40–49 50–59 60 Smoking Alcohol Caffeinated drinks Medication No. of bad habits 0 1–2 3
NVD (n ¼ 58)
%
N
%
N
5.4 54.1 29.7 8.1 2.7
2 20 11 3 1
17.2 37.9 31.0 12.1 1.7
10 22 18 7 1
1.7 6.8 66.1 33.3
1 4 37 18
3.4 8.6 74.1 8.6
2 5 43 5
27.1 69.5 3.4
16 41 2
22.4 74.1 3.4
13 43 2
P 0.369
0.549 0.709 0.347 0.001* 0.840
*P < 0.05.
Teaching characteristics Teaching characteristics and chi-square test of the VD and NVD groups are reported in Table 2. There were no significant differences between the VD and NVD groups in years of teaching, grades taught, and courses taught. A significantly higher rate of subjects in the VD group reported to use a loud voice in teaching than those in the NVD group (c2 (1) ¼ 9.76, P ¼ 0.001). The VD group had significantly more subjects using amplification in the classroom, such as a microphone, after they began experiencing voice problems than the NVD group (c2 (1) ¼ 6.17, P ¼ 0.007). Health condition Health condition and chi-square test of the VD and NVD groups are reported in Table 3. Significantly more subjects in the VD group had experienced upper respiratory infection, stress, and anxiety than those in the NVD group (c2 (1) ¼ 7.82 < 0.05; c2 (1) ¼ 3.30, P ¼ 0.002; c2 (1) ¼ 4.19, P ¼ 0.039; and c2 (1) ¼ 9.76, P ¼ 0.019, respectively). Among them, no subjects in the NVD group complained of anxiety, whereas 31.1% of the subjects in the VD group had this problem. The relative frequency distributions of numbers of diseases significantly differ for the two groups (c2 (1) ¼ 6.70, P ¼ 0.035). Subjects in the VD group were more likely to experience greater than or equal to three diseases, whereas subjects in the NVD group were more likely to experience two or fewer diseases. These health issues could have either contributed to or been the result of voice disorders. Voice symptoms and physical discomfort Voice symptoms, physical discomfort, and chi-square test of the VD and NVD groups are shown in Table 4. More subjects in the VD group reported having voice symptoms such as hoarseness and low-pitched speaking voice than those in the
Sheng Hwa Chen, et al
TABLE 2. Teaching Characteristics of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups
TABLE 4. Voice Symptoms and Physical Discomfort of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups
VD (n ¼ 59) NVD (n ¼ 58) Characteristics
%
N
%
N
Years in occupation 5 6–10 11–20 21
45.8 20.3 15.3 18.6
27 12 9 11
27.6 2 25.9 22.4 24.1
16 15 13 14
Grade taught 1–3 4–6 7–9 10–12
28.8 17.3 42.3 11.5
15 9 22 6
19.6 17.9 35.7 26.8
11 10 20 15
School courses Biology/Chemistry 3.8 Physics/Maths 13.2 Social Science 20.8 Elementary education 3.8 Special education 3.8 Music/Drama/Art 9.4 Language 34.0 Vocational education 5.7 Physical education 5.7
2 7 11 2 2 5 18 3 3
7.3 18.2 12.7 1.8 9.1 3.6 38.2 1.8 7.3
4 10 7 1 5 2 21 1 4
Loud voice Use amplification
39 48
46.8 58.6
22 0.001* 34 0.007*
P
0.214
0.610
79.6 81.4
NVD group (c2 (1) ¼ 7.16, P ¼ 0.004 and c2 (1) ¼ 4.19, P ¼ 0.000, respectively). The relative frequency distributions of number of voice symptoms significantly differ for the two groups (c2 (1) ¼ 57.31, P ¼ 0.000). Subjects in the VD group
TABLE 3. Health Condition of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups
Upper respiratory infection Nasal allergy Nasal septum deviation Hormonal problems Gastrointestinal reflux Stress Anxiety Head and neck surgery No. of diseases 0 1–2 3
VD (n ¼ 59)
NVD (n ¼ 58) %
%
N
33.3 41.2 9.8 3.9 11.8 47.5 32.1 27.6
14 21 5 2 6 19 9 16
12.5 30.4 57.1
7 17 32
N
P
3.3 1 0.002* 31.7 13 0.350 7.3 3 0.674 0.0 0 0.200 9.8 4 0.758 7.4 2 0.039* 0.0 0 0.019* 17.2 10 0.182 0.035* 28.1 16 36.8 21 35.1 20
VD (n ¼ 59)
NVD (n ¼ 58)
%
N
%
N
P
Voice symptoms Hoarseness Breathiness Tired voice Weak voice Strained voice Low note difficulty High note difficulty Low speaking voice High speaking voice Limited singing range
74.1 13.8 57.9 29.3 75.9 15.5 6.9 44.8 6.9 55.2
43 8 33 17 44 9 4 26 4 32
44.4 16.7 56.0 16.7 61.1 8.3 2.8 5.6 2.8 47.2
16 6 20 6 22 3 1 2 1 17
0.004* 0.704 0.899 0.166 0.128 0.310 0.169 0.000* 0.387 0.453
Physical discomfort Dryness Strain Ache Scratchiness Difficulty in swallowing
87.7 82.5 68.4 21.1 8.8
50 47 39 12 5
82.5 55.0 55.0 22.5 7.5
33 22 22 9 3
0.471 0.003* 0.178 0.865 0.823
No. of voice symptoms 0 1–2 3
25.4 11.9 62.7
15 7 37
84.5 12.1 3.4
49 0.000* 7 2
No. of physical discomfort 0 33.9 1–2 54.2 3 11.9
20 32 7
84.5 15.5 0.0
49 9 0
Professional help sought
33
25.6
11 0.002*
0.238
*P < 0.05.
*P < 0.05.
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Risk and Effects of Voice Problems for Teachers
55.9
0.000*
*P < 0.05.
were more likely to experience greater than or equal to three voice symptoms, whereas a high rate of subjects in the NVD group did not complain of any voice symptoms. Similar results were found for physical discomfort. More subjects in the VD group reported having physical discomfort of vocal strain than those in the NVD group (c2 (1) ¼ 7.34, P ¼ 0.003). Also, the relative frequency distributions of number of physical discomforts significantly differ for the two groups (c2 (1) ¼ 13.88, P ¼ 0.000). Subjects in the VD group were significantly more likely to seek medical help for voice problems than those in the NVD group (c2 (1) ¼ 8.14, P ¼ 0.002). Risk factors of voice problems Risk factors of voice problems and multivariate logistic regression of the VD and NVD groups are reported in Table 5. ORs of risk factors for voice problems are shown in Figure 1. Subjects who reported using a loud voice were at a significantly higher risk of developing a voice disorder (OR ¼ 4.34; P ¼ 0.009). The risk of using a loud voice while teaching for subjects in the VD group was about four times more frequent than those
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TABLE 5. Risk Factors of Voice Problems Associated With Demography, Teaching Characteristics, Living Habits, and Health Condition Risk Factors
OR
95% CI
P
Demography Age
1.12
0.97–1.28
0.116
Teaching Years in occupation Grade taught Using loud voice Using amplification
0.89 0.69 4.34 4.50
0.79–1.01 0.41–1.15 1.44–13.14 1.30–15.62
0.060 0.152 0.009* 0.018*
Living habits Number of bad habits
1.19
0.54–2.61
0.665
Health condition Number of diseases Head and neck surgeries
1.14 2.89
0.73–1.81 0.69–12.17
0.563 0.149
*P < 0.05.
in the NVD group. In addition, having a voice problem was associated with a higher instance of using amplification in the classroom (OR ¼ 4.50; P ¼ 0.018). Subjects in the VD group were about four times more likely to do so than those in the NVD group. There was no association between the risk of voice problems and age, years of teaching, grades taught, number of vices, number of diseases, or having received head and neck surgery. Effects of voice problems on daily life Effects of voice problems on daily life with chi-square and univariate logistic regression analyses are reported in Table 6. OR of effects for voice problems are shown in Figure 2. A chisquare test revealed that significantly more subjects in the VD
group reduced teaching course content, changed job opinions, reduced communicative ability, decreased phone calls, and experienced reduced social ability than those in the NVD group (c2 (1) ¼ 4.72, P ¼ 0.011; c2 (1) ¼ 34.11, P ¼ 0.000; c2 (1) ¼ 15.92, P ¼ 0.000; c2 (1) ¼ 6.59, P ¼ 0.005; and c2 (1) ¼ 17.89, P ¼ 0.000, respectively). In addition, the overall emotional state for VD subjects was significantly more likely to be influenced than that of NVD subjects (c2 (1) ¼ 21.36, P ¼ 0.000). Subjects in the VD group reported being upset at a significantly higher rate than subjects in the NVD group (c2 (1) ¼ 3.27, P ¼ 0.030). Univariate logistic regression analysis revealed that subjects in the VD group had a significantly higher risk of experiencing diminished job opinion, reduction of communicative ability, decreased numbers of phone calls, and reduction of social activity than those in the NVD group. This risk was present at rates of about 13, nine, five, and 10 times, respectively (OR ¼ 12.53, P ¼ 0.000; OR ¼ 9.11, P ¼ 0.000; OR ¼ 5.08, P ¼ 0.007; and OR ¼ 9.93, P ¼ 0.000, respectively). Besides, the emotional state was significantly influenced by voice problems about seven times more frequently than those in the NVD group (OR ¼ 7.19; P ¼ 0.000). Subjects in the VD group were about five times more likely to become upset than those in the NVD group (OR ¼ 4.55; P ¼ 0.038).
DISCUSSION This study is the first survey to investigate the risk factors and effects of voice problems for teachers in Taiwan. The advantage of this study in relation to previous studies is that demography, living habits, teaching characteristics, health condition, voice symptoms, and physical discomfort of teachers with voice disorders were differentiated from those of teachers without voice disorders. The results of this study helped us to find the jobrelated causes and impacts of voice problems for teachers.4,5,10,17,18
FIGURE 1. OR of risk factors for voice problems (*P < 0.05).
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Risk and Effects of Voice Problems for Teachers
TABLE 6. Pearson Chi-Square Test for Effects of Voice Problems on Daily Life Among VD (Voice Disorder) and NVD (No Voice Disorder) Groups, and Univariate Logistic Regression for Effects of Voice Problems Associated With Daily Life Pearson Chi-Square VD (n ¼ 59) Effects Teaching aspects Absenteeism Reduction in teaching hours Talk less in class Change in teaching style Reduction in course content Job opinions Change in overall job opinions Increase of job pressure Changing job Early retirement Communicative ability Reduction of overall communicative ability Repeating statements Avoidance of talking Trouble being understood Reduction in phone calls Social ability Reduction of overall social ability Avoidance of social activities Emotion Influence on overall emotional state Being upset Embarrassment Unsatisfactory job performance Change in personality Change in personal image
Univariate Logistic Regression
NVD (n ¼ 58)
%
N
%
N
P
OR
95% CI
P
6.8 2.3 47.7
3 1 21
15.6 6.3 56.3
5 2 18
0.217 0.379 0.463
0.40 0.35 0.71
0.09–1.79 0.03–4.02 0.28–1.77
0.229 0.399 0.464
59.1 18.2
26 8
50.0 0.0
16 0
0.431 0.011*
1.44
0.58–3.62
0.432
74.6
44
19.0
11
0.000*
12.53
5.20–30.22
0.000*
65.9 13.6 47.7
29 6 21
72.7 0.0 45.5
8 0 5
0.666 0.194 0.893
0.73
0.17–3.14
0.667
1.10
0.29–4.13
0.893
74.6
44
36.2
21
0.000*
0.19
0.09–0.43
0.000*
47.7 59.1 9.1 61.4
21 26 4 27
23.8 66.7 4.8 23.8
5 14 1 5
0.066 0.557 0.540 0.005*
0.34 0.72 0.50 5.08
0.11–1.10 0.24–2.14 0.05–4.77 1.57–16.43
0.071 0.558 0.547 0.007*
42.4
25
6.9
4
0.000*
9.93
3.18–31.02
0.000*
70.8
17
25.0
1
0.077
7.29
0.64–82.62
0.109
62.7
37
19.0
11
0.000*
7.19
3.10–16.68
0.000*
72.2 33.3 66.7 25.0 44.4
26 12 24 9 16
36.4 45.5 81.8 0.0 27.3
4 5 9 0 3
0.030* 0.464 0.336 0.065 0.310
4.55 0.60 0.44
1.09–18.99 0.15–2.37 0.08–2.39
0.038* 0.466 0.345
2.13
0.49–9.38
0.316
*P < 0.05.
Demographic characteristics, living habits, and teaching characteristics In this study, no significant difference was found for frequency of voice problems among age groups. Nor was there a significant difference for years of teaching. The relationship of age and voice problems in this study was inconsistent with Roy et al’s,6 Smith et al’s,18 and Russell et al’s9 findings for American and Australian teachers. They found a higher prevalence of voice problems in teachers older than 50 years. Roy et al6 reported that long durations of vocal use in teaching have cumulative effect on voice. Besides, hormonal changes in menopause and aging may further deteriorate vocal function.23,24 Those effects were not seen in this study. Maybe the sample size of the study is not large enough to show the effects on voice. The relationship of length of teaching and voice problems in this study
was consistent with Russell et al’s9 findings. However, this result disagreed with Kooijman et al’s,17 Smith et al’s,18 and Smith et al’s10 investigations for Dutch and American teachers. Smoking, alcohol, and caffeine did not have any apparent relationship with the frequency of voice problems. These results agreed with Roy et al’s6 findings for schoolteachers, and Miller and Verdolini’s20 reports for singing teachers. It may be because teachers were less likely to have used tobacco products and drink alcohol than the general population.4,6 The fact that teachers with voice disorders were more likely to take medicine than those without voice disorders can be explained as follows: (1) taking medicine is the result of voice problems because teachers who had voice problems often took medicines for physical discomfort and health problems; or (2) taking medicine is the cause of voice problems because teachers who
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Journal of Voice, Vol. 24, No. 2, 2010
FIGURE 2. OR of effects for voice problems (*P < 0.05). frequently took medicine may have experienced voice deterioration due to dehydration of the vocal folds;20 or (3) both. No significant difference was found for frequency of voice problems among school grades taught. Nor was there a difference for school courses. These results are inconsistent with Smith et al’s19 findings for American teachers. The differences between the two studies may be due to dissimilar teaching styles of the two populations. Different teaching styles may have different vocal loading, which therefore has different effects on the voice. Teachers with voice disorders in this study were more likely to report using loud voices in teaching than teachers without voice disorders. This result was consistent with Smith et al’s19 findings for American teachers, whereas disagreed with Gotaas and Starr’s12 investigations. Anderson13 proposed that teachers have to increase their speaking loudness level to maintain speech intelligibility and teaching efficiency in a classroom because the background noise is almost as loud as teacher’s voice. Long durations of loud talking may increase glottal closure that raises vocal fold impact stress, resulting in functional voice problems and vocal nodules.16,25,26 Voice disorders
can interfere with speech perception by students, which needs to be compensated for by increased vocal loudness of a teacher.19,27 The compensatory behavior may further deteriorate a teacher’s voice, ultimately decreasing a student’s learning experience. There were many more teachers in this study using microphones in the classroom after they began experiencing voice problems than those reported by Smith et al.18 Teachers with voice disorders were more likely to use this device than teachers without voice disorders. This may be because teachers who had experienced a voice problem benefit from this device in ways such as reduction in loudness level, lessening of necessary phonatory effort level, and decreased vocal loading.5,18 These advantages encourage them to use it in the classroom. Although using microphone related to voice disorders, other confounding factors can have a contributing effect as well. Health condition, voice symptoms, and physical discomfort Teachers with voice disorders were more likely to experience upper respiratory infection, stress, anxiety, and multiple
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Risk and Effects of Voice Problems for Teachers
diseases than teachers without voice disorders. These findings agreed with other reports for voice-disordered populations.6,28–30 Most teachers with voice disorders in this study had multiple vocal symptoms and physical discomfort. The most salient voice symptoms for the teachers were hoarseness and lowpitched speaking voice. The most prominent physical symptoms were strain. These symptoms were also found in Sapir et al’s11 reports for voice-disordered teachers. The similarities of the two studies suggested that hoarseness, low-pitched speaking voice, and strain may be the major self-perceived symptoms of voice disorders for teachers. Although teachers with voice disorders more frequently sought professional help than those without, almost half of the affected teachers did not seek assessment and treatment from health professionals. The low number of teachers who sought help was consistent with other findings for American and Australian teachers.6,9,11 Russell et al9 explained this phenomenon as that teachers view voice problems as occupational hazards and may not be aware of the help available to them. Roy et al6 suggested that this may be because teachers were reluctant to take time off from work for medical appointments, or that they fear physician advice to reduce voice use or change occupations. Risk factors and effects of voice problems In this study, the major risk factor of voice disorders for teachers was the loud voice. The probability of developing a voice disorder increased by a factor of four when a loud voice was used. It may be because classrooms in schools mostly have reverberations and high ambient noise levels.31,32 Teachers have to elevate their speaking intensity to enhance speech perception.14,33 In addition to this factor, genes may have influence on voice disorders. Research found that vocal fold composition is different between normal and pathological vocal fold.34,35 Some people are more prone to certain types of injury than others, whereas some people inherently have powerful voice and resist vocal illness as Ethel Merman, the American stage singer in the 20th Century.36 Because of physical differences in vocal physiology, people may need to work differently to avoid vocal problems during their career. Voice disorders found in this study have adverse effects on teachers’ daily lives. Teachers with voice disorders often changed their job satisfaction levels, experienced reduced communicative ability, decreased the number of phone calls they made, experienced reduced social ability, and felt that their emotional state was influenced. They were easily upset as a result of voice problems. These results were consistent with many studies that were previously undertaken.17,21,37,38 However, the results of this study disagreed with Sapir et al’s11 findings for American teachers, which showed the adverse effects that vocal problems had on teaching. It may be because the teachers in this study were working hard to maintain their quality of teaching in the classroom. The impacts of voice disorders on teachers in this study involved three levels of ‘‘disability’’ which were vocal impairment, limitation in daily activity, and restriction in
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participation in daily activity.39 According to Ma and Yiu’s21 statements, quality of life refers to the functioning of individuals in daily activities and individuals’ participation in these activities. Reduction of job satisfaction, communicative and social ability, and emotional stability for teachers in this study resulted in deterioration of life quality. Moreover, teaching quality may also be affected because dysphonia is detrimental to speech processing, which was identified as a degrading factor on the performance of students.5,27 The results of this study imply that reduction or elimination of risk factors for voice disorders would probably reduce the psychosocial impact on teachers. Therefore, a preventive voice care program should provide guidelines for current and future teachers to prevent them from developing voice problems. Based on the findings of the study, the focus of the program could be on reduction or elimination of using a loud voice in the classroom. The strategies of the program could include (1) explanation of the cause and effect of using a loud voice; (2) identification of a loud voice;37 (3) instruction in using a resonant voice technique to enhance the voice with the least effort;40 and (4) the use of a microphone in the classroom.5
CONCLUSIONS This study suggested that a loud voice maybe the important risk factor for development of voice disorders in teachers. Teachers who have experienced a voice problem often use a microphone to reduce their required phonatory effort. The effects of voice disorders on teachers were a change in job satisfaction, reduction of communicative ability, a decrease in phone calls, and a reduction of social ability. All of these influence the emotional state of the affected teachers and create the potential for even greater stress. They also limited and restricted daily activity of the teachers, which in turn deteriorated life quality. A preventive voice care program is necessary for current and future teachers. Follow-up studies will use a larger sample size to confirm the risk factors and effects of voice problems found in the current study. The loudness level of voice in teaching in this study is subjective information because it is self-reported by the teachers. Because one teacher’s personal rating might be different from the next, comparing the data among teachers is therefore difficult. Objective measurements of vocal output level in teaching are necessary to provide scientifically verifiable data. Because gene may be one of other factors for voice disorders, research and possible treatment are encouraged on this topic.
Acknowledgments This study was supported by grants from the National Science Council (NSC): 90-2413-H-227-001 and 91-2413-H-227-001. We are grateful to Yin-Tsui Huang, Yi-Shiun Yang, ChingWen Chang, Hsiu-Wen Chen, Den-Chiung Hsu, and Hsin-Yu Lin for their assistance in data collection and analysis of this research.
190 REFERENCES 1. Education Statistics. Taipei: Ministry of Education; 2006. Available at: http://www.edu.tw/EDU_WEB/EDU_MGT/STATISTICS/EDU7220001/ ebooks/edusta/p4-31.xls. Last accessed July 1, 2006. 2. Fritzell B. Voice disorders and occupations. Logoped Phoniatr Vocol. 1996;21:7-12. 3. Titze IR, Lemke J, Montequin D. Populations in the U.S. workforce who rely on voice as a primary tool of trade: a preliminary report. J Voice. 1997;11:254-259. 4. Sliwinska-Kowalska M, Niebudek-Bogusz E, Fiszer M, Los-Spychalska T, Kotylo P, Sznurowska-Przygocka B, Modrzewska M. The prevalence and risk factors for occupational voice disorders in teachers. Folia Phoniatr Logop. 2006;58:85-101. 5. Roy N, Merrill RM, Thibeault S, Gray SD, Smith EM. Voice disorders in teachers and the general population: effects on work performance, attendance, and future career choices. J Speech Lang Hear Res. 2004;47: 542-551. 6. Roy N, Merrill RM, Thibeault S, Parsa RA, Gray SD, Smith EM. Prevalence of voice disorders in teachers and the general population. J Speech Lang Hear Res. 2004;47:281-293. 7. Sala E, Airo E, Olkinuora P, et al. Vocal loading among day care center teachers. Logoped Phoniatr Vocol. 2002;27:21-28. 8. Yiu EM-L. Impact and prevention of voice problems in the teaching profession: embracing the consumers’ view. J Voice. 2002;16:215-228. 9. Russell A, Oates J, Greenwook KM. Prevalence of voice problems in teachers. J Voice. 1998;12:467-479. 10. Smith E, Gray SD, Dove H, Kirchner L, Heras H. Frequency and effects of teachers’ voice problems. J Voice. 1997;11:81-87. 11. Sapir S, Keidar A, Mathers-Schmidt B. Vocal attrition in teachers: survey findings. Eur J Disord Commun. 1993;28:177-185. 12. Gotaas C, Starr CD. Vocal fatigue among teachers. Folia Phoniatr. 1993;45: 120-129. 13. Anderson K. The problem of classroom acoustics: the typical classroom soundscape is a barrier to learning. Semin Hear. 2004;25:117-129. 14. Tung CY. A relationship study on the school noise and teachers’ teaching voice loudness, vocal health, and acoustic signs change. J Health Educ. 2000;14:113-136. 15. Mattiske JA, Oates JM, Greenwood KM. Vocal problems among teachers: a review of prevalence, causes, prevention and treatment. J Voice. 1998;12: 489-499. 16. Jiang JJ, Titze IR. Measurement of vocal fold intraglottal pressure and impact stress. J Voice. 1994;8:132-144. 17. Kooijman PGC, Thomas G, Graamans K, de Jong FICRS. Psychosocial impact of the teacher’s voice throughout the career. J Voice. 2007;21:316-324. 18. Smith E, Lemke J, Taylor M, Kirchner HL, Hoffman H. Frequency of voice problems among teachers and other occupations. J Voice. 1998;12:480-488. 19. Smith E, Kirchner HL, Taylor M, Hoffman H, Lemke JH. Voice problems among teachers: differences by gender and teaching characteristics. J Voice. 1998;12:328-334. 20. Miller MK, Verdolini K. Frequency and risk factors for voice problems in teachers of singing and control subjects. J Voice. 1995;9:348-362.
Journal of Voice, Vol. 24, No. 2, 2010 21. Ma EP-M, Yiu EM-L. Voice activity and participation profile: assessing the impact of voice disorders on daily activities. J Speech Lang Hear Res. 2001;44:511-524. 22. Jacobson BH, Johnson A, Grywalski C, Silbergleit A, Jacobson G, Benninger MS, Newman CW. The Voice Handicap Index (VHI): development and validation. Am J Speech Lang Pathol. 1997;6:66-70. 23. Abitbol J. Normal voice maturation: hormones and age. In: Benninger MS, Murry T, eds. The Performer’s Voice. San Diego: Plural Publishing; 2006. 24. Scheider B, van Trotsenburg M, Hanke G, Bigenzahn W, Huber J. Voice impairment and menopause. Menopause. 2004;11:151-158. 25. Hess MM, Verdolini K, Bierhals W, Mansmann U, Gross M. Endolaryngeal contact pressures. J Voice. 1998;12:50-67. 26. Peterson KL, Verdolini-Marston K, Barkmeier JM, Hoffman HT. Comparison of aerodynamic and electroglottographic parameters in evaluating clinically relevant voicing patterns. Ann Otol Rhinol Laryngol. 1994;103: 335-346. 27. Rogerson J, Dodd B. Is there an effect of dysphonic teachers’ voices on children’s processing of spoken language? J Voice. 2005;19:47-60. 28. Roy N, Bless DM. Personality traits and psychological factors in voice pathology: a foundation for future research. J Speech Lang Hear Res. 2000;43:737-748. 29. Van Dick R, Wagner U. Stress and strain in teaching: a structural equation approach. Br J Educ Psychol. 2001;71:243-259. 30. Nichol H, Morrison M, Rammage L. Interdisciplinary approach to functional voice disorders: the psychiatrist’s role. Otolaryngol Head Neck Surg. 1993;108:643-647. 31. Crandell C, Smaldino J. Classroom acoustics: understanding barriers to learning [Special issue on classroom acoustics]. Volta Rev 1999;101. 32. Pekkarinen E, Viljanen V. Acoustic conditions for speech communication in classrooms. Scand Audiol. 1991;20:257-263. 33. Irwin RJ, McAuley SF. Relations among temporal acuity, hearing loss, and the perception of speech distorted by noise and reverberation. J Acoust Soc Am. 1987;81:1557-1565. 34. Thibeault SL. Advances in our understanding of the Reinke space. Curr Opin Otolaryngol Head Neck Surg. 2005;13:148-151. 35. Thibeault SL, Hirschi SD, Gray SD. DNA microarray gene expression analysis of a vocal fold polyp and granuloma. J Speech Lang Hear Res. 2003;46:491-502. 36. Kellow B. Ethel Merman: A Life. New York: Viking Press; 2007. 37. Thomas G, Kooijman PGC, Donders ART, Cremers CWRJ, de Jong FICRS. The voice handicap of student-teachers and risk factors perceived to have a negative influence on the voice. J Voice. 2007;21:325-336. 38. Guimara˜es I, Abberton E. An investigation of the Voice Handicap Index with speakers of Portuguese: preliminary data. J Voice. 2004;18: 71-82. 39. World Health Organization. International Classification of Impairment, Disability and Handicap-Beta 1: A Manual of Dimensions of Disablement and Participation. Geneva: World Health Organization; 1997. 40. Verdolini K. Resonant voice therapy. In: Stemple JC, ed. Voice Therapy: Clinical Case Studies. 2nd ed). San Diego: Singular Publishing Group; 2000.
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Appendix. Questionnaire DEMOGRAPHIC INFORMATION 1. Name _________ 2. Sex: ________ 3. Birth date ___/____/____ (month/date/year)
LIVING HABITS 4. Do you have the following habits?
Smoking Drinking Caffeine drinks (eg, coffee, tea, coke, soda) Taking medicine
Yes Yes Yes
No No No
Yes
No
Please choose a proper answer to the following questions by putting a ‘‘O’’ in the box. HEALTH CONDITION 5. Have you had the following diseases? Upper respiratory infection Nasal allergy Nasal septum deviation Hormonal problems Gastrointestinal reflux Stress Anxiety
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Risk and Effects of Voice Problems for Teachers
Yes Yes Yes Yes Yes Yes Yes
No No No No No No No
8. Which grade do you teach in schools? 1–3 4–6 7–9 10–12 9. Which course do you teach in schools? Biology Chemistry Physics Mathematics Social science Elementary education Special education Music Drama Art Language Vocational education Physical education Others (Please specify_____________) 10. How loud do you use your voice in class? Small loudness Moderate loudness Large loudness 11. Do you use a microphone in class? Yes No
VOICE SYMPTOMS AND PHYSICAL DISCOMFORT 12. Have you had a voice problem? Yes. Please indicate the frequency of the problems:
6. Have you had the following surgeries? Sometimes Throat surgery Thyroid gland surgery Chest surgery Heart surgery Endotracheal intubation Other surgeries
Yes Yes
No No
Yes Yes Yes
No No No
Yes No (Please specify _____________)
TEACHING CHARACTERISTICS 7. How many years have you been teaching in schools? 5 6–10 11–20 21
Often
Always
13. Have you had symptoms on your voice? Yes. Please indicate the symptoms: Hoarseness Breathiness Tired voice Weak voice Strained voice Low note difficulty High note difficulty Low speaking voice High speaking voice Limited singing range Others (Please specify__________) No 14. Have you had discomfort on your throat? Yes. Please indicate the discomfort: Dryness Strain Ache
No
192 Scratchiness Difficulty in swallowing Others (Please specify_________) No 15. Do you seek professional help for your voice problem? Yes No
EFFECTS OF VOICE PROBLEMS 16. Have you adjusted teaching method due to your voice problems? Yes. Please indicate the ways of adjustment: Ask for leaves Reduce teaching hours Talk less in class Change teaching style Reduce course content Others (Please specify_____________) No 17. Have you changed opinions on teaching profession due to your voice problems? Yes. Please indicate the opinions of change: Change overall job opinions Increase job pressure Change job Retire early
Journal of Voice, Vol. 24, No. 2, 2010
Others (Please specify_____________) No 18. Have your voice problems affected your communicative ability? Yes. Please indicate the ability affected: Reduce overall communicative ability Need to repeat statements Avoid talking to others Is difficult to understand me Reduce numbers of phone calls Others (Please specify_____________) No 19. Have your voice problems affected your social ability? Yes. Please indicate the ability affected: Reduce overall social ability Avoid social activities Others (Please specify_____________) No 20. Have your voice problems affected your emotion? Yes. Please indicate the emotion affected: Influence overall emotional state Is upset Is embarrassed Is unsatisfied with job performance Change personality Change personal image Others (Please specify_____________) No
between teaching and nonteaching groups makes their respective voice-related problems fundamentally different. The use of this method allows us to analyze the influence of different teaching characteristics, such as years in occupation, courses taught, vocal loudness in the classroom, etc on voice problems for teachers. Also, previous studies did not seek to include the influence of demography, living habits, and health condition on voice problems for people of the same occupation. Moreover, it is difficult to determine the job-related effects of voice problems on psychosocial aspects for teachers. The objectives of the study are (1) to investigate risk factors of voice problems for teachers with voice disorders as compared to teachers without voice disorders, and (2) to investigate the effects of voice problems on daily life in the two groups. These results could help to develop preventive voice care programs in schools to reduce the frequency and severity of voice problems, the impact of voice disorders, and overall intervention cost. METHODS Subjects Five elementary, middle, and high schools in Taipei City were randomly selected for the study. All 254 teachers in these schools were given a self-reporting questionnaire. One hundred and fifty-two questionnaires were returned, of which only 117 questionnaires were correctly filled out, creating a response rate of 46%. The investigators divided the subjects into two groups based on the frequency of voice problems in the questionnaires. A four-point scale was used to rate the answer by the subjects, where ‘‘0 ¼ never,’’ ‘‘1 ¼ sometimes,’’ ‘‘2 ¼ often,’’ and ‘‘3 ¼ always.’’ Subjects whose score was equal to or higher than ‘‘2’’ in the questions were placed into a voice disorder group (VD group); the others were placed into the no voice disorder group (NVD group). The VD group consisted of 59 subjects with a mean age of 40.5 years. The
184 NVD group consisted of 58 subjects with a mean age of 42.2 years. Questionnaire The questionnaire in the study was designed based on the investigators’ clinical experiences and other reports in professional voice disorder literature (Appendix).5,8,10,18,19,21,22 The information elicited in the questionnaire was (1) demographic characteristics of gender and age, (2) living habits such as smoking, consumption of alcohol and caffeine, etc, (3) teaching characteristics such as years in occupation, grades taught, self-reported vocal loudness, etc, (4) health condition associated with voice problems such as upper respiratory infection, nasal allergy, gastrointestinal reflux, etc, (5) experience voice symptoms such as hoarseness, breathiness, tired voice, etc, (6) experience physical discomfort associated with voice problems such as dryness, strain, ache, etc, and (7) adverse effects of voice problems on daily life. Demographics, living habits, teaching characteristics, and health condition in the questionnaires may represent risk factors for voice problems of the subjects. Adverse effects of voice problems on daily life may determine functional impact of voice problems on teaching aspects, job opinions, communicative ability, social ability, and emotion. Statistical analysis The Pearson chi-square test was used to examine the significant differences of VD and NVD groups with respect to demographic characteristics, living habits, teaching characteristics, health condition, voice symptoms, physical discomfort, and daily life. Multivariate logistic regression was used to evaluate the odds ratios (ORs) and 95% confidence intervals (CIs) between VD and NVD groups, and demographic characteristics, living habits, teaching characteristics, and health condition to find risk factors for voice problems. The NVD group was considered the reference, or low risk group, compared to the VD group. Univariate logistic regression was used to evaluate the effects of voice problems between teaching style, job opinions, communicative ability, social ability, and emotion, and VD and NVD groups. The negative findings in teaching style, job opinions, communicative ability, and emotion are considered the reference group, compared to the positive findings of these variables. All calculations were conducted using the SPSS 12.0 (SPSS Inc., Chicago, IL). RESULTS Demographic characteristics and living habits More females than males participated in the study, of which 98 were females and 19 were males. Demography, living habits, and chi-square test of the VD and NVD groups are reported in Table 1. Although no significant difference was found in age groups between VD and NVD, the subjects in the 20–29year range had a higher rate of being in the NVD group than the VD group. VD and NVD groups had approximately equal numbers of subjects in alcohol and caffeine consumption, and number of vices. However, the VD group had significantly more subjects taking medicine than the NVD group (c2 (1) ¼ 9.01, P ¼ 0.001).
Journal of Voice, Vol. 24, No. 2, 2010
TABLE 1. Demography and Living Habits of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups VD (n ¼ 59)
Age (yr) 20–29 30–39 40–49 50–59 60 Smoking Alcohol Caffeinated drinks Medication No. of bad habits 0 1–2 3
NVD (n ¼ 58)
%
N
%
N
5.4 54.1 29.7 8.1 2.7
2 20 11 3 1
17.2 37.9 31.0 12.1 1.7
10 22 18 7 1
1.7 6.8 66.1 33.3
1 4 37 18
3.4 8.6 74.1 8.6
2 5 43 5
27.1 69.5 3.4
16 41 2
22.4 74.1 3.4
13 43 2
P 0.369
0.549 0.709 0.347 0.001* 0.840
*P < 0.05.
Teaching characteristics Teaching characteristics and chi-square test of the VD and NVD groups are reported in Table 2. There were no significant differences between the VD and NVD groups in years of teaching, grades taught, and courses taught. A significantly higher rate of subjects in the VD group reported to use a loud voice in teaching than those in the NVD group (c2 (1) ¼ 9.76, P ¼ 0.001). The VD group had significantly more subjects using amplification in the classroom, such as a microphone, after they began experiencing voice problems than the NVD group (c2 (1) ¼ 6.17, P ¼ 0.007). Health condition Health condition and chi-square test of the VD and NVD groups are reported in Table 3. Significantly more subjects in the VD group had experienced upper respiratory infection, stress, and anxiety than those in the NVD group (c2 (1) ¼ 7.82 < 0.05; c2 (1) ¼ 3.30, P ¼ 0.002; c2 (1) ¼ 4.19, P ¼ 0.039; and c2 (1) ¼ 9.76, P ¼ 0.019, respectively). Among them, no subjects in the NVD group complained of anxiety, whereas 31.1% of the subjects in the VD group had this problem. The relative frequency distributions of numbers of diseases significantly differ for the two groups (c2 (1) ¼ 6.70, P ¼ 0.035). Subjects in the VD group were more likely to experience greater than or equal to three diseases, whereas subjects in the NVD group were more likely to experience two or fewer diseases. These health issues could have either contributed to or been the result of voice disorders. Voice symptoms and physical discomfort Voice symptoms, physical discomfort, and chi-square test of the VD and NVD groups are shown in Table 4. More subjects in the VD group reported having voice symptoms such as hoarseness and low-pitched speaking voice than those in the
Sheng Hwa Chen, et al
TABLE 2. Teaching Characteristics of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups
TABLE 4. Voice Symptoms and Physical Discomfort of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups
VD (n ¼ 59) NVD (n ¼ 58) Characteristics
%
N
%
N
Years in occupation 5 6–10 11–20 21
45.8 20.3 15.3 18.6
27 12 9 11
27.6 2 25.9 22.4 24.1
16 15 13 14
Grade taught 1–3 4–6 7–9 10–12
28.8 17.3 42.3 11.5
15 9 22 6
19.6 17.9 35.7 26.8
11 10 20 15
School courses Biology/Chemistry 3.8 Physics/Maths 13.2 Social Science 20.8 Elementary education 3.8 Special education 3.8 Music/Drama/Art 9.4 Language 34.0 Vocational education 5.7 Physical education 5.7
2 7 11 2 2 5 18 3 3
7.3 18.2 12.7 1.8 9.1 3.6 38.2 1.8 7.3
4 10 7 1 5 2 21 1 4
Loud voice Use amplification
39 48
46.8 58.6
22 0.001* 34 0.007*
P
0.214
0.610
79.6 81.4
NVD group (c2 (1) ¼ 7.16, P ¼ 0.004 and c2 (1) ¼ 4.19, P ¼ 0.000, respectively). The relative frequency distributions of number of voice symptoms significantly differ for the two groups (c2 (1) ¼ 57.31, P ¼ 0.000). Subjects in the VD group
TABLE 3. Health Condition of the VD (Voice Disorder) and NVD (No Voice Disorder) Groups
Upper respiratory infection Nasal allergy Nasal septum deviation Hormonal problems Gastrointestinal reflux Stress Anxiety Head and neck surgery No. of diseases 0 1–2 3
VD (n ¼ 59)
NVD (n ¼ 58) %
%
N
33.3 41.2 9.8 3.9 11.8 47.5 32.1 27.6
14 21 5 2 6 19 9 16
12.5 30.4 57.1
7 17 32
N
P
3.3 1 0.002* 31.7 13 0.350 7.3 3 0.674 0.0 0 0.200 9.8 4 0.758 7.4 2 0.039* 0.0 0 0.019* 17.2 10 0.182 0.035* 28.1 16 36.8 21 35.1 20
VD (n ¼ 59)
NVD (n ¼ 58)
%
N
%
N
P
Voice symptoms Hoarseness Breathiness Tired voice Weak voice Strained voice Low note difficulty High note difficulty Low speaking voice High speaking voice Limited singing range
74.1 13.8 57.9 29.3 75.9 15.5 6.9 44.8 6.9 55.2
43 8 33 17 44 9 4 26 4 32
44.4 16.7 56.0 16.7 61.1 8.3 2.8 5.6 2.8 47.2
16 6 20 6 22 3 1 2 1 17
0.004* 0.704 0.899 0.166 0.128 0.310 0.169 0.000* 0.387 0.453
Physical discomfort Dryness Strain Ache Scratchiness Difficulty in swallowing
87.7 82.5 68.4 21.1 8.8
50 47 39 12 5
82.5 55.0 55.0 22.5 7.5
33 22 22 9 3
0.471 0.003* 0.178 0.865 0.823
No. of voice symptoms 0 1–2 3
25.4 11.9 62.7
15 7 37
84.5 12.1 3.4
49 0.000* 7 2
No. of physical discomfort 0 33.9 1–2 54.2 3 11.9
20 32 7
84.5 15.5 0.0
49 9 0
Professional help sought
33
25.6
11 0.002*
0.238
*P < 0.05.
*P < 0.05.
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Risk and Effects of Voice Problems for Teachers
55.9
0.000*
*P < 0.05.
were more likely to experience greater than or equal to three voice symptoms, whereas a high rate of subjects in the NVD group did not complain of any voice symptoms. Similar results were found for physical discomfort. More subjects in the VD group reported having physical discomfort of vocal strain than those in the NVD group (c2 (1) ¼ 7.34, P ¼ 0.003). Also, the relative frequency distributions of number of physical discomforts significantly differ for the two groups (c2 (1) ¼ 13.88, P ¼ 0.000). Subjects in the VD group were significantly more likely to seek medical help for voice problems than those in the NVD group (c2 (1) ¼ 8.14, P ¼ 0.002). Risk factors of voice problems Risk factors of voice problems and multivariate logistic regression of the VD and NVD groups are reported in Table 5. ORs of risk factors for voice problems are shown in Figure 1. Subjects who reported using a loud voice were at a significantly higher risk of developing a voice disorder (OR ¼ 4.34; P ¼ 0.009). The risk of using a loud voice while teaching for subjects in the VD group was about four times more frequent than those
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TABLE 5. Risk Factors of Voice Problems Associated With Demography, Teaching Characteristics, Living Habits, and Health Condition Risk Factors
OR
95% CI
P
Demography Age
1.12
0.97–1.28
0.116
Teaching Years in occupation Grade taught Using loud voice Using amplification
0.89 0.69 4.34 4.50
0.79–1.01 0.41–1.15 1.44–13.14 1.30–15.62
0.060 0.152 0.009* 0.018*
Living habits Number of bad habits
1.19
0.54–2.61
0.665
Health condition Number of diseases Head and neck surgeries
1.14 2.89
0.73–1.81 0.69–12.17
0.563 0.149
*P < 0.05.
in the NVD group. In addition, having a voice problem was associated with a higher instance of using amplification in the classroom (OR ¼ 4.50; P ¼ 0.018). Subjects in the VD group were about four times more likely to do so than those in the NVD group. There was no association between the risk of voice problems and age, years of teaching, grades taught, number of vices, number of diseases, or having received head and neck surgery. Effects of voice problems on daily life Effects of voice problems on daily life with chi-square and univariate logistic regression analyses are reported in Table 6. OR of effects for voice problems are shown in Figure 2. A chisquare test revealed that significantly more subjects in the VD
group reduced teaching course content, changed job opinions, reduced communicative ability, decreased phone calls, and experienced reduced social ability than those in the NVD group (c2 (1) ¼ 4.72, P ¼ 0.011; c2 (1) ¼ 34.11, P ¼ 0.000; c2 (1) ¼ 15.92, P ¼ 0.000; c2 (1) ¼ 6.59, P ¼ 0.005; and c2 (1) ¼ 17.89, P ¼ 0.000, respectively). In addition, the overall emotional state for VD subjects was significantly more likely to be influenced than that of NVD subjects (c2 (1) ¼ 21.36, P ¼ 0.000). Subjects in the VD group reported being upset at a significantly higher rate than subjects in the NVD group (c2 (1) ¼ 3.27, P ¼ 0.030). Univariate logistic regression analysis revealed that subjects in the VD group had a significantly higher risk of experiencing diminished job opinion, reduction of communicative ability, decreased numbers of phone calls, and reduction of social activity than those in the NVD group. This risk was present at rates of about 13, nine, five, and 10 times, respectively (OR ¼ 12.53, P ¼ 0.000; OR ¼ 9.11, P ¼ 0.000; OR ¼ 5.08, P ¼ 0.007; and OR ¼ 9.93, P ¼ 0.000, respectively). Besides, the emotional state was significantly influenced by voice problems about seven times more frequently than those in the NVD group (OR ¼ 7.19; P ¼ 0.000). Subjects in the VD group were about five times more likely to become upset than those in the NVD group (OR ¼ 4.55; P ¼ 0.038).
DISCUSSION This study is the first survey to investigate the risk factors and effects of voice problems for teachers in Taiwan. The advantage of this study in relation to previous studies is that demography, living habits, teaching characteristics, health condition, voice symptoms, and physical discomfort of teachers with voice disorders were differentiated from those of teachers without voice disorders. The results of this study helped us to find the jobrelated causes and impacts of voice problems for teachers.4,5,10,17,18
FIGURE 1. OR of risk factors for voice problems (*P < 0.05).
Sheng Hwa Chen, et al
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Risk and Effects of Voice Problems for Teachers
TABLE 6. Pearson Chi-Square Test for Effects of Voice Problems on Daily Life Among VD (Voice Disorder) and NVD (No Voice Disorder) Groups, and Univariate Logistic Regression for Effects of Voice Problems Associated With Daily Life Pearson Chi-Square VD (n ¼ 59) Effects Teaching aspects Absenteeism Reduction in teaching hours Talk less in class Change in teaching style Reduction in course content Job opinions Change in overall job opinions Increase of job pressure Changing job Early retirement Communicative ability Reduction of overall communicative ability Repeating statements Avoidance of talking Trouble being understood Reduction in phone calls Social ability Reduction of overall social ability Avoidance of social activities Emotion Influence on overall emotional state Being upset Embarrassment Unsatisfactory job performance Change in personality Change in personal image
Univariate Logistic Regression
NVD (n ¼ 58)
%
N
%
N
P
OR
95% CI
P
6.8 2.3 47.7
3 1 21
15.6 6.3 56.3
5 2 18
0.217 0.379 0.463
0.40 0.35 0.71
0.09–1.79 0.03–4.02 0.28–1.77
0.229 0.399 0.464
59.1 18.2
26 8
50.0 0.0
16 0
0.431 0.011*
1.44
0.58–3.62
0.432
74.6
44
19.0
11
0.000*
12.53
5.20–30.22
0.000*
65.9 13.6 47.7
29 6 21
72.7 0.0 45.5
8 0 5
0.666 0.194 0.893
0.73
0.17–3.14
0.667
1.10
0.29–4.13
0.893
74.6
44
36.2
21
0.000*
0.19
0.09–0.43
0.000*
47.7 59.1 9.1 61.4
21 26 4 27
23.8 66.7 4.8 23.8
5 14 1 5
0.066 0.557 0.540 0.005*
0.34 0.72 0.50 5.08
0.11–1.10 0.24–2.14 0.05–4.77 1.57–16.43
0.071 0.558 0.547 0.007*
42.4
25
6.9
4
0.000*
9.93
3.18–31.02
0.000*
70.8
17
25.0
1
0.077
7.29
0.64–82.62
0.109
62.7
37
19.0
11
0.000*
7.19
3.10–16.68
0.000*
72.2 33.3 66.7 25.0 44.4
26 12 24 9 16
36.4 45.5 81.8 0.0 27.3
4 5 9 0 3
0.030* 0.464 0.336 0.065 0.310
4.55 0.60 0.44
1.09–18.99 0.15–2.37 0.08–2.39
0.038* 0.466 0.345
2.13
0.49–9.38
0.316
*P < 0.05.
Demographic characteristics, living habits, and teaching characteristics In this study, no significant difference was found for frequency of voice problems among age groups. Nor was there a significant difference for years of teaching. The relationship of age and voice problems in this study was inconsistent with Roy et al’s,6 Smith et al’s,18 and Russell et al’s9 findings for American and Australian teachers. They found a higher prevalence of voice problems in teachers older than 50 years. Roy et al6 reported that long durations of vocal use in teaching have cumulative effect on voice. Besides, hormonal changes in menopause and aging may further deteriorate vocal function.23,24 Those effects were not seen in this study. Maybe the sample size of the study is not large enough to show the effects on voice. The relationship of length of teaching and voice problems in this study
was consistent with Russell et al’s9 findings. However, this result disagreed with Kooijman et al’s,17 Smith et al’s,18 and Smith et al’s10 investigations for Dutch and American teachers. Smoking, alcohol, and caffeine did not have any apparent relationship with the frequency of voice problems. These results agreed with Roy et al’s6 findings for schoolteachers, and Miller and Verdolini’s20 reports for singing teachers. It may be because teachers were less likely to have used tobacco products and drink alcohol than the general population.4,6 The fact that teachers with voice disorders were more likely to take medicine than those without voice disorders can be explained as follows: (1) taking medicine is the result of voice problems because teachers who had voice problems often took medicines for physical discomfort and health problems; or (2) taking medicine is the cause of voice problems because teachers who
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FIGURE 2. OR of effects for voice problems (*P < 0.05). frequently took medicine may have experienced voice deterioration due to dehydration of the vocal folds;20 or (3) both. No significant difference was found for frequency of voice problems among school grades taught. Nor was there a difference for school courses. These results are inconsistent with Smith et al’s19 findings for American teachers. The differences between the two studies may be due to dissimilar teaching styles of the two populations. Different teaching styles may have different vocal loading, which therefore has different effects on the voice. Teachers with voice disorders in this study were more likely to report using loud voices in teaching than teachers without voice disorders. This result was consistent with Smith et al’s19 findings for American teachers, whereas disagreed with Gotaas and Starr’s12 investigations. Anderson13 proposed that teachers have to increase their speaking loudness level to maintain speech intelligibility and teaching efficiency in a classroom because the background noise is almost as loud as teacher’s voice. Long durations of loud talking may increase glottal closure that raises vocal fold impact stress, resulting in functional voice problems and vocal nodules.16,25,26 Voice disorders
can interfere with speech perception by students, which needs to be compensated for by increased vocal loudness of a teacher.19,27 The compensatory behavior may further deteriorate a teacher’s voice, ultimately decreasing a student’s learning experience. There were many more teachers in this study using microphones in the classroom after they began experiencing voice problems than those reported by Smith et al.18 Teachers with voice disorders were more likely to use this device than teachers without voice disorders. This may be because teachers who had experienced a voice problem benefit from this device in ways such as reduction in loudness level, lessening of necessary phonatory effort level, and decreased vocal loading.5,18 These advantages encourage them to use it in the classroom. Although using microphone related to voice disorders, other confounding factors can have a contributing effect as well. Health condition, voice symptoms, and physical discomfort Teachers with voice disorders were more likely to experience upper respiratory infection, stress, anxiety, and multiple
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diseases than teachers without voice disorders. These findings agreed with other reports for voice-disordered populations.6,28–30 Most teachers with voice disorders in this study had multiple vocal symptoms and physical discomfort. The most salient voice symptoms for the teachers were hoarseness and lowpitched speaking voice. The most prominent physical symptoms were strain. These symptoms were also found in Sapir et al’s11 reports for voice-disordered teachers. The similarities of the two studies suggested that hoarseness, low-pitched speaking voice, and strain may be the major self-perceived symptoms of voice disorders for teachers. Although teachers with voice disorders more frequently sought professional help than those without, almost half of the affected teachers did not seek assessment and treatment from health professionals. The low number of teachers who sought help was consistent with other findings for American and Australian teachers.6,9,11 Russell et al9 explained this phenomenon as that teachers view voice problems as occupational hazards and may not be aware of the help available to them. Roy et al6 suggested that this may be because teachers were reluctant to take time off from work for medical appointments, or that they fear physician advice to reduce voice use or change occupations. Risk factors and effects of voice problems In this study, the major risk factor of voice disorders for teachers was the loud voice. The probability of developing a voice disorder increased by a factor of four when a loud voice was used. It may be because classrooms in schools mostly have reverberations and high ambient noise levels.31,32 Teachers have to elevate their speaking intensity to enhance speech perception.14,33 In addition to this factor, genes may have influence on voice disorders. Research found that vocal fold composition is different between normal and pathological vocal fold.34,35 Some people are more prone to certain types of injury than others, whereas some people inherently have powerful voice and resist vocal illness as Ethel Merman, the American stage singer in the 20th Century.36 Because of physical differences in vocal physiology, people may need to work differently to avoid vocal problems during their career. Voice disorders found in this study have adverse effects on teachers’ daily lives. Teachers with voice disorders often changed their job satisfaction levels, experienced reduced communicative ability, decreased the number of phone calls they made, experienced reduced social ability, and felt that their emotional state was influenced. They were easily upset as a result of voice problems. These results were consistent with many studies that were previously undertaken.17,21,37,38 However, the results of this study disagreed with Sapir et al’s11 findings for American teachers, which showed the adverse effects that vocal problems had on teaching. It may be because the teachers in this study were working hard to maintain their quality of teaching in the classroom. The impacts of voice disorders on teachers in this study involved three levels of ‘‘disability’’ which were vocal impairment, limitation in daily activity, and restriction in
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participation in daily activity.39 According to Ma and Yiu’s21 statements, quality of life refers to the functioning of individuals in daily activities and individuals’ participation in these activities. Reduction of job satisfaction, communicative and social ability, and emotional stability for teachers in this study resulted in deterioration of life quality. Moreover, teaching quality may also be affected because dysphonia is detrimental to speech processing, which was identified as a degrading factor on the performance of students.5,27 The results of this study imply that reduction or elimination of risk factors for voice disorders would probably reduce the psychosocial impact on teachers. Therefore, a preventive voice care program should provide guidelines for current and future teachers to prevent them from developing voice problems. Based on the findings of the study, the focus of the program could be on reduction or elimination of using a loud voice in the classroom. The strategies of the program could include (1) explanation of the cause and effect of using a loud voice; (2) identification of a loud voice;37 (3) instruction in using a resonant voice technique to enhance the voice with the least effort;40 and (4) the use of a microphone in the classroom.5
CONCLUSIONS This study suggested that a loud voice maybe the important risk factor for development of voice disorders in teachers. Teachers who have experienced a voice problem often use a microphone to reduce their required phonatory effort. The effects of voice disorders on teachers were a change in job satisfaction, reduction of communicative ability, a decrease in phone calls, and a reduction of social ability. All of these influence the emotional state of the affected teachers and create the potential for even greater stress. They also limited and restricted daily activity of the teachers, which in turn deteriorated life quality. A preventive voice care program is necessary for current and future teachers. Follow-up studies will use a larger sample size to confirm the risk factors and effects of voice problems found in the current study. The loudness level of voice in teaching in this study is subjective information because it is self-reported by the teachers. Because one teacher’s personal rating might be different from the next, comparing the data among teachers is therefore difficult. Objective measurements of vocal output level in teaching are necessary to provide scientifically verifiable data. Because gene may be one of other factors for voice disorders, research and possible treatment are encouraged on this topic.
Acknowledgments This study was supported by grants from the National Science Council (NSC): 90-2413-H-227-001 and 91-2413-H-227-001. We are grateful to Yin-Tsui Huang, Yi-Shiun Yang, ChingWen Chang, Hsiu-Wen Chen, Den-Chiung Hsu, and Hsin-Yu Lin for their assistance in data collection and analysis of this research.
190 REFERENCES 1. Education Statistics. Taipei: Ministry of Education; 2006. Available at: http://www.edu.tw/EDU_WEB/EDU_MGT/STATISTICS/EDU7220001/ ebooks/edusta/p4-31.xls. Last accessed July 1, 2006. 2. Fritzell B. Voice disorders and occupations. Logoped Phoniatr Vocol. 1996;21:7-12. 3. Titze IR, Lemke J, Montequin D. Populations in the U.S. workforce who rely on voice as a primary tool of trade: a preliminary report. J Voice. 1997;11:254-259. 4. Sliwinska-Kowalska M, Niebudek-Bogusz E, Fiszer M, Los-Spychalska T, Kotylo P, Sznurowska-Przygocka B, Modrzewska M. The prevalence and risk factors for occupational voice disorders in teachers. Folia Phoniatr Logop. 2006;58:85-101. 5. Roy N, Merrill RM, Thibeault S, Gray SD, Smith EM. Voice disorders in teachers and the general population: effects on work performance, attendance, and future career choices. J Speech Lang Hear Res. 2004;47: 542-551. 6. Roy N, Merrill RM, Thibeault S, Parsa RA, Gray SD, Smith EM. Prevalence of voice disorders in teachers and the general population. J Speech Lang Hear Res. 2004;47:281-293. 7. Sala E, Airo E, Olkinuora P, et al. Vocal loading among day care center teachers. Logoped Phoniatr Vocol. 2002;27:21-28. 8. Yiu EM-L. Impact and prevention of voice problems in the teaching profession: embracing the consumers’ view. J Voice. 2002;16:215-228. 9. Russell A, Oates J, Greenwook KM. Prevalence of voice problems in teachers. J Voice. 1998;12:467-479. 10. Smith E, Gray SD, Dove H, Kirchner L, Heras H. Frequency and effects of teachers’ voice problems. J Voice. 1997;11:81-87. 11. Sapir S, Keidar A, Mathers-Schmidt B. Vocal attrition in teachers: survey findings. Eur J Disord Commun. 1993;28:177-185. 12. Gotaas C, Starr CD. Vocal fatigue among teachers. Folia Phoniatr. 1993;45: 120-129. 13. Anderson K. The problem of classroom acoustics: the typical classroom soundscape is a barrier to learning. Semin Hear. 2004;25:117-129. 14. Tung CY. A relationship study on the school noise and teachers’ teaching voice loudness, vocal health, and acoustic signs change. J Health Educ. 2000;14:113-136. 15. Mattiske JA, Oates JM, Greenwood KM. Vocal problems among teachers: a review of prevalence, causes, prevention and treatment. J Voice. 1998;12: 489-499. 16. Jiang JJ, Titze IR. Measurement of vocal fold intraglottal pressure and impact stress. J Voice. 1994;8:132-144. 17. Kooijman PGC, Thomas G, Graamans K, de Jong FICRS. Psychosocial impact of the teacher’s voice throughout the career. J Voice. 2007;21:316-324. 18. Smith E, Lemke J, Taylor M, Kirchner HL, Hoffman H. Frequency of voice problems among teachers and other occupations. J Voice. 1998;12:480-488. 19. Smith E, Kirchner HL, Taylor M, Hoffman H, Lemke JH. Voice problems among teachers: differences by gender and teaching characteristics. J Voice. 1998;12:328-334. 20. Miller MK, Verdolini K. Frequency and risk factors for voice problems in teachers of singing and control subjects. J Voice. 1995;9:348-362.
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Appendix. Questionnaire DEMOGRAPHIC INFORMATION 1. Name _________ 2. Sex: ________ 3. Birth date ___/____/____ (month/date/year)
LIVING HABITS 4. Do you have the following habits?
Smoking Drinking Caffeine drinks (eg, coffee, tea, coke, soda) Taking medicine
Yes Yes Yes
No No No
Yes
No
Please choose a proper answer to the following questions by putting a ‘‘O’’ in the box. HEALTH CONDITION 5. Have you had the following diseases? Upper respiratory infection Nasal allergy Nasal septum deviation Hormonal problems Gastrointestinal reflux Stress Anxiety
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Risk and Effects of Voice Problems for Teachers
Yes Yes Yes Yes Yes Yes Yes
No No No No No No No
8. Which grade do you teach in schools? 1–3 4–6 7–9 10–12 9. Which course do you teach in schools? Biology Chemistry Physics Mathematics Social science Elementary education Special education Music Drama Art Language Vocational education Physical education Others (Please specify_____________) 10. How loud do you use your voice in class? Small loudness Moderate loudness Large loudness 11. Do you use a microphone in class? Yes No
VOICE SYMPTOMS AND PHYSICAL DISCOMFORT 12. Have you had a voice problem? Yes. Please indicate the frequency of the problems:
6. Have you had the following surgeries? Sometimes Throat surgery Thyroid gland surgery Chest surgery Heart surgery Endotracheal intubation Other surgeries
Yes Yes
No No
Yes Yes Yes
No No No
Yes No (Please specify _____________)
TEACHING CHARACTERISTICS 7. How many years have you been teaching in schools? 5 6–10 11–20 21
Often
Always
13. Have you had symptoms on your voice? Yes. Please indicate the symptoms: Hoarseness Breathiness Tired voice Weak voice Strained voice Low note difficulty High note difficulty Low speaking voice High speaking voice Limited singing range Others (Please specify__________) No 14. Have you had discomfort on your throat? Yes. Please indicate the discomfort: Dryness Strain Ache
No
192 Scratchiness Difficulty in swallowing Others (Please specify_________) No 15. Do you seek professional help for your voice problem? Yes No
EFFECTS OF VOICE PROBLEMS 16. Have you adjusted teaching method due to your voice problems? Yes. Please indicate the ways of adjustment: Ask for leaves Reduce teaching hours Talk less in class Change teaching style Reduce course content Others (Please specify_____________) No 17. Have you changed opinions on teaching profession due to your voice problems? Yes. Please indicate the opinions of change: Change overall job opinions Increase job pressure Change job Retire early
Journal of Voice, Vol. 24, No. 2, 2010
Others (Please specify_____________) No 18. Have your voice problems affected your communicative ability? Yes. Please indicate the ability affected: Reduce overall communicative ability Need to repeat statements Avoid talking to others Is difficult to understand me Reduce numbers of phone calls Others (Please specify_____________) No 19. Have your voice problems affected your social ability? Yes. Please indicate the ability affected: Reduce overall social ability Avoid social activities Others (Please specify_____________) No 20. Have your voice problems affected your emotion? Yes. Please indicate the emotion affected: Influence overall emotional state Is upset Is embarrassed Is unsatisfied with job performance Change personality Change personal image Others (Please specify_____________) No