Abstract
Teachers are the backbone of any civilized society as they are the keepers of knowledge, wisdom and values. Lack of infrastructure, manpower and resources makes voice the most important tool for a teacher. Teachers need to speak loudly for long periods often under unfavourable circumstances. Increased vocal effort and incorrect phonation techniques can lead to vocal fold tissue damage and vocal fold pathologies and hence voice problems producing adverse effects on teaching performance. To study the prevalence of voice disorders in Indian female secondary school teacher population. To identify the risk factors for the development of voice disorders. A multicentric, cross-sectional observational study of 200 teachers were conducted in 4 schools over a period of 2 years. Female teachers who gave consent and were willing for follow up were included in the study. Details were collected using a structured questionnaire. Subjective analysis by VHI, perceptual analysis by GRABS score, acoustic analysis and direct visualization using Hopkins 70° rigid laryngoscope were done.The prevalence of voice disorders was 18.5%. Risk factors identified were age group 41–60 years, repeated respiratory allergies, comorbidities, constitutional symptoms, increased number of years of teaching and number of lecture hours per week. VHI, GRABS, Acoustic analysis findings were consistent with Rigid Laryngoscopic finding making them effective tools in the assessment of voice.
Keywords: Voice disorders in teachers, VHI, GRABS, Acoustic analysis, Rigid laryngoscopy, Indian female teachers
Introduction
Teachers are the backbone of any civilized society as they propagate knowledge, wisdom and social values. Their job entails speaking loudly for a long period of time causing vocal fatigue, and this makes them susceptible to hyper-functional voice disorders with or without vocal fold damage. Voice disorders manifest as vocal fatigue, hoarseness, throat pain or discomfort, weak voice, dryness and lower pitch. Abnormal voice produces adverse effects on teaching performance and communicative ability leading to a lesser quality of teaching and increased absenteeism [1].
In India, a low teacher to student ratio, lack of infrastructure (such as microphones, compact classrooms, good noise-less ventilation systems), teachers’ repeated exposure to upper respiratory tract infections (due to dust, pollution, and tropical weather) and other airborne irritants complicate the problems of teachers in India, along with insufficient formal training on vocal health and hygiene such as voice proper posture, respiration, release of tension in the vocal apparatus, resonance, and voice projection when communicating can contribute to vocal problems amongst teachers which make this study relevant.
The aims of the study were; 1) prevalence of voice disorders in female secondary school teacher population; 2) to identify the risk factors for the development of voice disorders in them.
Materials and Methods
It was a multi-centric, cross- sectional observational clinical study conducted in 4 English medium secondary schools over a period of 2 years. Institutional Ethics Committee approval was taken and permission from the principals of various schools were obtained. 200 female secondary school teachers who gave consent for the study and were willing for follow up were included in the study. To keep uniformity within the samples, only female teachers were included. Male teachers and female teachers who did not give consent and were not willing for follow up were excluded.
The teachers were informed about the study and appropriate consent was taken before enrolling them. A structured questionnaire (Fig. 1) was distributed and necessary information was collected from each teacher which included age, lifestyle habits (smoking, alcohol and caffeine intake), health condition( allergy, other medical conditions), teaching characteristics (number of years of teaching, number of lectures per week, number of pupils in each classroom), environmental factors (chalk, dust, dry air, temperature, background noise), voice symptoms (hoarseness, tiredness, vocal fatigue) and physical discomforts (throat pain, dry mouth, laryngopharyngeal reflux LPR). Voice Handicap Index (VHI) (Fig. 2) was assessed using a separate questionnaire which comprised of 30 questions and answers of which were rated on a five-point scale for each of the 3 subscales namely (physical [P], emotional [E] and functional [F]). Perceptual analysis of their voice was done by GRABS scoring and severity of scoring was quantified for each parameter (Grade, Roughness, Breathiness, Asthenia, Strain) from 0 to 3. Acoustic analysis (perturbation analysis) was performed using Dr Speech software. The perturbation parameters like jitter and shimmer was taken into consideration. The normal range for jitter, shimmer is less than 0.5%, 3% respectively. Detailed endoscopic high definition pictures of the confirmatory laryngoscopic findings were obtained using Hopkins 70° rigid laryngoscope.
Fig. 1.
Case record form
Fig. 2.
Voice handicap index (VHI)
Results
All the 200 teachers were subjected to 70° rigid laryngoscopy. Out of them, 163 (81.5%) who had normal Rigid Laryngoscopic (RL) findings were considered as Group I. The 37 (18.5%) teachers who had pathological findings along with voice problems were categorised as Group II (Table 1). Majority of the teachers in the pathalogical group were between 41–60 years, although a large propotion of the study group also belonged to the same category. Age was found to be a stastically significant factor (Table 2).
Table 1.
Rigid laryngoscopic findings of the study group
| RL findings | No. of teachers (n = 200) | Percentage |
|---|---|---|
| Normal (Group I) | 163 | 81.5 |
| Pathological (Group II) | 37 | 18.5 |
Table 2.
Comparison of Age with Rigid laryngoscopic findings
| Variables | Group I Normal (n = 163) |
Group II Pathological (n = 37) |
p value |
|---|---|---|---|
| Age (years) | |||
| 21–30 | 18(11%) | 2(5.4%) |
< 0.001** (Fischer exact test) |
| 31–40 | 62(38%) | 1(2.7%) | |
| 41–50 | 57(35%) | 20(54.1%) | |
| 51–60 | 26(16%) | 13(35.1%) | |
| > 60 | 0(0%) | 1(2.7%) |
Among the 4 teachers with history of smoking, 3 (75%) belonged to the pathological group. 32 (86.5%) out of 37 teachers gave history of regular caffeine intake. The results obtained with regard to smoking and caffeine intake were statistically significant.History of alcohol consumption was given by 1 (2.7%) out of 37 teachers of pathological group which showed no statistical significance (Table 3).
Table 3.
Comparison of the variables with the pathological and normal groups
| Variables | GroupI Normal (n = 163) |
Group II Pathological (n = 37) |
p value |
|---|---|---|---|
| Smoking | |||
| No | 162(99.4%) | 34(91.9%) |
0.003** (Chi square) |
| Yes | 1(0.6%) | 3(8.1%) | |
| Alcohol | |||
| No | 160(98.2%) | 36(97.3%) |
0.735 (Chi square) |
| Yes | 3(1.8%) | 1(2.7%) | |
| Caffeine | |||
| No | 63(38.7%) | 5(13.5%) |
0.004** (Chi square) |
| Yes | 100(61.3%) | 32(86.5%) | |
| Allergy | |||
| No | 141(86.5%) | 17(46.1%) |
< .001** (Chi square) |
| Yes | 20(12.3%) | 20(54.1%) | |
| Medical history | |||
| No | 143(87.7%) | 26(70.3%) |
0.008** (Chi square) |
| Yes | 20(12.3%) | 11(29.7%) | |
| Use of Chalk | |||
| No | 5(3.1%) | 0 |
0.281 (Chi square) |
| Yes | 158(96.9%) | 37(100%) | |
| Unfavourable working conditions | |||
| No | 70(62.9%) | 11(29.7%) |
0.049** (Chi square) |
| Yes | 93(57.1%) | 26(70.3%) | |
| Background noise | |||
| No | 79(48.5%) | 13(35.1%) |
0.142 (Chi square) |
| Yes | 84(51.5%) | 24(64.9%) | |
| ENT symptoms | |||
| No | 140(85.9%) | 30(81.1%) |
0.498 (Fischer exact test) |
| Yes | 23(14.1%) | 7(18.9%) | |
| Constitutional symptoms | |||
| No | 142(87.1%) | 23(62.2%) |
< 0.001** (Fischer exact test) |
| Yes | 21(12.8%) | 14(37.8%) |
Out of the 37 teachers belonging to pathological group, 20 (54.1%) had history of allergy (dust, drugs, food), while among the rest of the 163 teachers only 20 (12.3%) was found to be allergic and the results were statistically significant. The history of chalk use and exposure to chalk dust was present in all teachers of the pathological group. However, it was seen in (96.9%) of the normal group as well. The results were comparable but were not statistically significant. 26 (70.3%) teachers of pathological group had history of exposure to unfavourable working conditions (dust, poor acoustics), whereas only 57.1% among their normal counterparts had exposure to these and the results were statistically significant. Among the teachers of pathological group, 24 (64.9%) were exposed to loud background noise (traffic, noise from neighbouring classrooms) in comparison to (51.5%) of their normal counterparts. The results though comparable, were not found to be statistically significant (Table 3).
Out of the 31 teachers with positive history of other medical illness, 11 belonged to the pathological group. Positive correlation was obtained for hypothyroidism (4), asthma (3), sinusitis (4). 7(18.9%) of the pathological group had ENT symptoms (nasal obstruction and rhinorrhoea) when compared to 23 (14.2%) teachers of the normal group. The results showed no statistical significance. Among the 37 teachers of pathological group, 14 (37.8%) suffered from at least one of constitutional symptoms (headache, LPR, neck pain, sore throat) and the result were statistically significant (Table 3).
The teachers of the pathological group had more number of years of teaching experience and lecture hours per week than the normal group. The results on comparison was statistically significant (Table 4).
Table 4.
Comparison of Years of teaching, lectures hours weeks and Number of pupils of normal and pathological groups
| Variables | Group I Normal |
Group II Pathological |
p value |
|---|---|---|---|
| No. of years of teaching | 14.88 ± 8.07 | 23.78 ± 8.68 | < 0.001** |
| No. lectures hours weeks | 20.09 ± 6.11 | 25.38 ± 7.35 | < 0.001** |
| No. of Pupil | 53.18 ± 15.64 | 51.57 ± 13.58 | 0.563 |
The teachers were divided into two groups based on VHI, i.e. VHI < 30 (169) and VHI > 30 (31). VHI of teachers of group I showed a mean of 9.76 ± 6.58 while that of Group II was found to be 31.65 ± 12. The results were statistically significant (Table 5).
Table 5.
Comparison of various methods of assessment with rigid laryngoscopy
| Variables | Group I Normal |
Group II Pathological |
p Value | ||
|---|---|---|---|---|---|
| VHI (Mean) | 9.76 ± 6.58 | 31.65 ± 12.78 |
< 0.001** (Student t test) |
||
| < 30 | 163(100%) | 6(16.2%) | |||
| ≥ 30 | 0(0%) | 31(83.7%) | |||
|
GRABS (Number of teachers) |
< 0.001** (Chi-square test) |
||||
| ≤ 1 | 163 (100%) | 6 (16.2%) | |||
| > 2 | 0 (0%) | 31(83.7%) | |||
|
ACOUSTIC PARAMETERS (Number of teachers) |
Chi-square test | ||||
| SHIMMER | ≤ 0.001** | ||||
| Normal range ≤ 3 | ≤ 3 | 131 (80.3%) | 4 (10.8%) | ||
| > 3 | 32(19.7%) | 33(89.2%) | |||
| JITTER | ≤ 0.001** | ||||
| Normal range ≤ 0.5 | ≤ 0.5 | 141(86.5%) | 4(10.8%) | ||
| > 0.5 | 22(13.5%) | 33(89.8%) |
The teachers included in the study were classified into 2 groups on the basis of GRABS scale, i.e. GRABS ≤ 1 and GRABS > 2. All the 31(83.7%) teachers with GRABS score > 2 belonged to the pathological group and the results were found to be statistically significant (Table 5).
Acoustic parameters (shimmer and jitter) of both the groups were compared. 89.1% teachers of pathological group had both shimmer and jitter values outside the normal range (Table 5).
Discussion
School teachers have high propensity to develop voice disorders owing to the nature of their work [2]. Females are more prone to develop voice disorders than their male counterparts due to anatomical difference of the larynx and vocal cords such as shorter anteroposterior diameter [3] and thinner vocal cords [3] and reduced amounts of hyaluronic acid in the superficial layer [4]. All of which contribute to increased vocal fold injury and scarring. The prevalence estimate for voice disorders in female school teachers in our study was 18.5%, which is slightly higher than that of Smith et al. [5] and Russell et al. [6] whose studies showed prevalence rate of 14.6% and 15.9% respectively. However as per study conducted by Arati et al. [7] amongst Indian teachers (males and females) 81% of them had experienced voice disorders in their lifetime. This disparity in the results could be due to a lack of a clear operational definition of voice disorder.
The age range of 40–59 years was found to represent a high-risk group for the reporting of voice disorders in our study. The finding is consistent with the results of Smith E et al. [5] and Russell et al. [6] who reported higher prevalence of voice problems among teachers older than 50 years. This is attributed to the cumulative effect of vocal use and tissue injury combined with the biological aging factors. However in a study done in Indian teachers by Arati et al. [7] no significant association was seen.
Lifestyle habits such as smoking, alcohol, and caffeine intake did not have any apparent relationship with the frequency of voice problems among the school teachers according to Roy et al. [8]. However, smoking and caffeine intake had significant association with the voice problems in our study. This study did not show any significant association of alcohol on voice disorders among teachers, which is consistent with the study conducted by Roy et al. [8].Our study revealed that the frequency of voice disorders is significantly higher among those with recurrent allergies. This is in accordance with study by Roy et al. and Spiegel et al. Chen SH et al. [9] claimed that teachers with voice disorders are more likely to have multiple medical diseases, stress, anxiety than the teachers without voice disorders. As per Roy et al. [8] teachers are more prone to allergies, asthma, sinus problems, laryngitis etc. In our study 4 teachers had chronic sinusitis with bronchitis and 3 were asthmatics and they belonged to the pathological group. It was noticed that 4 out of 8 teachers with hypothyroidism also belonged to the pathological group and the results were significant. It is due to myxoedema of the vocal cords.
In Sadegh Seipanahi et al. study, workplace conditions like bad acoustics, poor ventilation, lack of humidity, exposure to blackboard chalk dust [10] and high background noise [11] had adverse affect on voice of teachers. According to Sala et al. high background noise levels compelled teachers to speak loudly resulting in vocal strain.
Roy et al. [8] stated that conditions like common cold, nasal blockage, laryngitis etc. were some of the contributing factors in the development of voice disorders and more so among teachers who were consistently exposed to allergens and unfavourable working conditions, with a p value < 0.001 for each factor. Their results did not equate with our data, since our study had only 7 teachers of the pathological group who had ENT complaints. In a study conducted by Cheng et al. [9], teachers with voice disorder experienced symptoms like headache, sore throat, laryngopharyngeal reflux, stress, anxiety. In our study 18.9% of the teachers of the pathological group had constitutional symptoms, while these symptoms were seen only in 5.5% of the normal group and the results were statistically significant.
Roy N et al. [8] in his study stated that, long durations of vocal use had a cumulative effect on the voice resulting in voice disorders. In our data, years of teaching experience and number of lecture hours per week both showed statistical significance. A study conducted by Preciado J et al. [12], revealed lack of association between number of pupil and voice disorders amongst teachers. Arati et al.’s study on Indian teachers also did not reveal any significant association. Results of our study too were consistent with other studies showing no statistical significance.
Lira Luce et al. stated, teachers working in a noisy environment had higher rate of voice disorders and higher score in VHI [13]. Their study showed, VHI score higher in teachers with pathological laryngoscopic findings than others, with p value 0.026. The outcome of our study showed that the comparison of VHI for the teachers of pathological group was statistically significant and consistent with previous studies. A study by Meulenbroek and De Jong compared GRABS with laryngoscopic findings which showed, amongst patients with voice problems 96% had positive laryngoscopic findings and hence consistent with the results of our study, showing that amongst 37 teachers of pathological group, 31 had moderate to severe dysphonia (GRABS > 2), while the remaining 6 belonged to the mild dysphonic group (GRABS ≤ 1). Laukkanen et al.’s study correlated an increase in jitter and shimmer with fatigue of voice. Another study conducted by Ali Dehqan and Ronald C Scherer (2013) also showed that female school teachers had higher values of perturbation acoustic parameters. Our findings were consistent with their results.
The following recommendations such as, adopting a healthy diet (Avoid fast/spicy/deep fried food, adequate water intake, avoid skipping breakfast and include more fruit juices) and lifestyle (avoid smoking, tobacco and alcohol, avoid shouting/screaming/mimicry, avoid throat clearing, do not exert when sick, take assistance when voice change noticed and avoid lying down immediately after meals), adequate voice rest, appropriate vocal training, use of newer teaching methods (eg microphones and projectors) and early attendance to medical problems are proposed. The various methods of assessment such as VHI, GRABS scoring, Acoustic Analysis were significant and comparable with Rigid laryngoscopic findings. Hence these could be used as effective tools in the evaluation of voice.
The limitations of the study were that it could not compare the effect of removal of irritants like chalk, smoking, tobacco or alcohol as the data was found to be skewed. Also, we could not compare the voice outcomes of teachers teaching in classrooms with different number of pupils (such as 30 compared to 50) and a separate study needs to be carried out to compare the same.
Conclusion
The significant risk factors in the causation of voice disorders among teachers derived from the study were: Age group 41–60 years, repeated respiratory allergies, coexisting medical conditions, presence of constitutional symptoms, increased number of years of teaching and number of lecture hours per week. Convenient methods of assessment, such as VHI, GRABS and Acoustic Analysis, can henceforth be used reliably in the place of the more cumbersome rigid laryngoscopy. Voice disorders in school teachers is a notable issue and protective pre-emptive measures forms the cornerstone of management.
Funding
No funding received or provided during this study.
Compliance ith Ethical Standards
Conflict of interest
No conflict of interest during this case report.
Informed consent
Written, informed and valid consent taken from teachers.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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