MINISTRY OF EDUCATION

MINISTRY OF HEALTH

AND TRAINING

HANOI MEDICAL UNIVERSITY

LE ANH TUAN

STUDY ON VOICE DISORDERS AND ASSESSMENT OF
INTERVENTION RESULTS AMONG FEMALE PRIMARY
SCHOOL TEACHERS AT GIA LAM DISTRICT, HANOI
Major: Ear – Nose - Throat
Code : 9720155

SUMMARY OF MEDICAL DOCTORAL DISSERTATION

HA NOI – 2022


THE THESIS WAS FULFILLED AT
HANOI MEDICAL UNIVERSITY

Supervisor: Assoc. Prof. Luong Thi Minh Huong

Reviewer 1:
Reviewer 2:
Reviewer 3:

. Prof Pham Thi Van Anh

The dissertation is defended before the Committee of Hanoi
Medical University
At

:

on /

/

20

For further detail of the dissertation, please search at:
-

The national library

-

The library of Hanoi Medical University


THESIS RELATED PUBLICATIONS
1. Le Anh Tuan, Nguyen Duy Duong, Bien Van Hoan, Luong Thi Minh
Huong. Status of voice disorders of female primary school teachers and
some related factors at Gia Lam District, Hanoi in 2016. Vietnam Ear Nose
Throat Journal, October 3, 2017, Volume 62-37, p. 43-51.
2. Le Anh Tuan, Luong Thi Minh Huong, Nguyen Duy Duong. Evaluation of
treatment results for voice disorders of female primary school teachers at

Gia Lam district, Hanoi. Journal of Medical Research, vol. 139, issue 3,
April 2021, p. 37-44.
3. Le Anh Tuan, Luong Thi Minh Huong, Pham Tien Dung, Nguyen Thanh
Quan. Status and effectiveness of voice disorder interventions among female
primary school teachers in Hanoi. Vietnam Medical Journal, vol. 150, January,
issue 2, 2022, p. 186-190.


1
INTRODUCTION
Voice disorder (VD) or Dysphonia is an abnormality of one or
more characteristics of the voice, including disturbances in pitch,
pitch, pitch, or tone. (VD) caused by laryngeal causes is largely due
to dysfunction of the laryngeal muscle system stemming from vocal
abuse behaviors.
Teachers are subject to using voice as a tool, so they have a higher
risk of schizophrenia compared to other occupations. The quality of the
teacher's voice directly affects the effectiveness of the training for
students, especially primary school students. The diagnosis of voice
disorders is based on many methods, in which laryngoscopy allows
more accurate diagnosis of laryngeal diseases, thereby providing
appropriate treatment procedures. Treatment of VD includes surgical
treatment, medical treatment, and methods to correct pronunciation
behavior: voice training and voice hygiene.
In Vietnam, there have been a number of studies on VD in primary
school teachers such as a study by Ngo Ngoc Lien (2006) on 1033
female primary school teachers showing that the rate of physical
damage to the larynx is 20.81 %. Up to now, there has not been any
research using laryngeal strobosopy and negative analysis to diagnose
and classify VD in primary school teachers to study the relationship

between comorbid Ear- Nose-Throat (ENT) dysfunction in people with
VD and to evaluate the effectiveness of the training method. voice for
teachers with VD. Therefore, we carry out the topic " Study on voice
disorders and assessment of intervention results among female primary
school teachers at Gia Lam district, Hanoi" with the following research
objectives:
1. To describe functional, physical and ENT disorders related to
voice disorders in primary school teachers in Gia Lam district, Hanoi.
2. To evaluate of the effectiveness of interventions in the treatment
of speech disorders in primary school teachers.


2
SCIENTIFIC AND PRACTICAL MEANINGS OF THE THESIS
Voice disorder (VD) is a common disease in the world, especially in
professions such as teachers. The research has provided solutions to
intervene in VD problems such as health education communication,
combined with voice hygiene, 4 voice training exercises, and medical
treatment. These very positive intervention results are a premise for
large-scale research and application with many other high-risk subjects,
with a longer time to evaluate its sustainability. Through this study, we
also see the necessity to include screening for teachers to detect VD in
the periodic health check-up program to detect early teachers with VD
and guide how to treat and prevent them. Proposing to include the
evaluation VD criteria for teachers' occupational diseases. Educational
Universities and Colleges should have a curriculum on voice hygiene
and standard pronunciation methods as well as prevention methods for
voice disorders for future teachers.
NEW CONCLUSIONS FROM THE THESIS
 The first study applied subjective and objective methods in

diagnosing VD, especially using laryngoscopy to help classify
and diagnose more accurately laryngeal pathologies from which
to propose procedures. suitable treatment. The study evaluated the
relationship between ENT diseases and VD for effective
comprehensive treatment of VD.
 Research on the application of voice therapy (voice training) in
the treatment of VD in primary school teachers and confirm the
effectiveness of the voice training method in the treatment of VD.
 Research on a large scale, all primary school teachers in Gia Lam
district. Research, follow-up, intervention, and evaluation
methodically through 3 stage.
STRUCTURE OF THE THESIS
The thesis consists of 108 pages excluding appendixes, tables,
charts, diagrams, figures and 128 references, of which: 2 pages of
introduction and research objectives, 37 pages of literature review and
research methods 20 pages, research results 21 pages, discussion 25
pages, conclusions 2 pages and recommendations 1 page.


3
CHAPTER 1
LITERATURE REVIEW
1.1. Study history
1.1.1. Epidemiological study of voice disorders in the world
In the last decades of the twentieth century, in the world, there have
been many research works on different aspects of VD. The studies show
that the VD rate has a clear occupational nature. According to studies in
the world, teachers have been identified as the profession with the highest
rate of VD.
1.1.2. Epidemiological of voice disorders of female primary school

teachers in Vietnam
In Vietnam, the data on VD in the community is still very modest. In
2000, the first publication on the epidemiology of VD in primary school
teachers appeared by Pham Thi Ngoc, the results showed that 29.9% of
teachers had VD. Tran Duy Ninh (2011) research on VD problems of
primary school teachers in Thai Nguyen city showed that the prevalence
of VD in the 2 study seasons was: 76.20% - 79.33%.
1.2. Pronunciation mechanism and physical properties of voice
1.2.1. Pronunciation mechanism
The process of speech production is very complex, requiring the
smooth and synchronous coordination of many different organs.

Nose, throat, mouth,
tongue…

VOICE

UPPER RESPIRATORY
(Resonance)
Phonetic
level

Muscle in the larynx
(vocal cord muscle)

Vibrating part (larynx:
forming the vocal cords)

Upper respiratory
anatomy

(diaphragm)

Lower respiratory tract
(lungs: vocal resources)

Diagram 1.1: Simulation of pronunciation physiology

Personal
level


4
1.2.2. Characteristics of the voice
The characteristics of the sound quality: The analysis of the sound
quality is essentially the survey and analysis of the instability, the
unevenness of the fundamental frequency and the amplitude of the
acoustic signal according to indicators such as: Jitter, Shimmer,
Harmonicity, these indicators can be analyzed by PRAAT software
program.
1.3. Voice disorder (VD)
1.3.1. Definition of voice disorders
Definition of VD: communication disorders related to injury or
defect in the larynx or abnormal or inappropriate vocal function related
to pitch, intensity, or vocal quality. Voice disturbances can range in
severity from hoarseness (dysphonia), to complete loss of voice
(aphonia) because the vocal cords do not vibrate during vocalization.
1.3.3. Causes and pathogenesis of voice disorders:
The main cause of VD is commonly referred to by many authors as
the noun vocal abuse.
Changes in pitch

and intensity
(weak, tired, short
of breath...)

Trigger
factors:
talkative,
ENT
pathological

Voice
disorder

Vocal cord injury
(fibrous granules,
vocal polyp..)

Try to
pronounce
to
compensate

Efforts to increase
pronunciation
effect

Diagram 1.2: Pathological spiral of voice disorders


5

1.3.5. Detect and evaluate voice disorders
In fact, the diagnosis of VD is sometimes very easy but sometimes
difficult. To accurately assess the VD, it is necessary to combine many
factors.
PATIENT’S SELF
ASSESSMENT

VOICE

PHONOLOGICAL
RESONACE

TIMBRE

FEELING ASSESSMENT

SOUND ANALYSIS

LARYNX

LARYNGEAL STROBOSCOPY

LUNG

AERODYNAMICS

Diagram 1.4: Diagramming methods of probing pronunciation
function
1.4. Voice disorders treatment in female primary school teachers
1.4.1. Principles of treatment of voice disorders in teachers

VD in teachers is functional VD (behavioral etiology) mainly due to
muscular tension VD, caused by voice abuse. So the basic principle in
treatment is to adjust the pronunciation behavior of teachers through
voice hygiene and voice training programs. In addition, the intervention
regimen may be accompanied by medical or surgical treatment.
1.4.2. Treatment of voice disorders by means of pronunciation
behavior correction
1.4.2.1. Treatment of indirect voice disorders
By indirect methods such as: communication and health education,
vocal hygiene education to influence the patient's pronunciation
behavior.
DON'T: Clear your throat; Speak in a noisy environment; Using
stimulants; Speak when you feel tired; Pronouncing over your range.
DO: Rest your voice when there is an upper respiratory tract
infection or hoarseness; Drink enough water and divide it into several
times, (1.5-2 liters of water/day).


6
1.4.2.2. Direct voice disorder treatment (Voice Training)
In this study, we apply exercises for teachers' VD according to the
prototypes of Mathienson and Boone, including 4 specific exercises as
follows:
- Exercise 1: Breathing exercise (15 minutes): Purpose: Belly
breathing to increase the volume of air in one breath, the air column in
the trachea is strong, the source of pronunciation (vocal vibration)
- Exercise 2 (Yawn-sigh - 10 minutes): Purpose: To regulate the
activity of the laryngeal muscles and especially the vibration of the
vocal cords.
- Exercise 3 (Humming - 15 minutes): Purpose: Help teachers know

how to push the breath out before speaking so that the voice can go
further.
- Exercise 4 (Blow the pipe - 10 minutes): Purpose: Regulate the
flow of air when speaking to ensure the longest and most stable
sentence
VOICE RESONANCEARTICULATOR PHONETICS

EXERCISE 3

LARYNX

EXERCISE 2
EXERCISE 4

LUNG

EXERCISE 1

Diagram 1.5: Mechanism of impact of exercises on pronunciation
organs
1.4.3. Treatment of voice disorders by internal medicine and surgery
- Internal medicine: When there is inflammation in the larynx
- Surgical treatment of VD: When there is physical damage to the
larynx
- Treatment of comorbidities: LPR treatment; infections treatments
in the nose and sinuses.


7
CHAPTER 2

METHODOLOGY
2.1. Study subject: female primary school teachers who are directly
teaching at 20 primary schools in Gia Lam district - Hanoi.
2.1.3. Study location:
The study was conducted in 20/24 public primary schools at Gia
Lam district,
Hanoi.
2.1.4. Study durattion:
From May 2015 to September 2019.
2.2. Study methodology
2.2.1. Study design: Divided into 2 phases
- Objective 1: A cross-sectional study to determine the prevalence of
VD and
related factors.
- Objective 2: Non-controlled interventional study.
2.2.2. Sample
2.2.2.1. Sample size in a cross-sectional study for an objective of one
Apply the formula to estimate a rate for a population:

n  Z12 /2

p(1  p)
( p. )2

Substituting the values in calculates the minimum sample size of
n=395, adding 10% does not meet the minimum sample size of 435
teachers.
In fact, after sifting from a list of more than 600 primary school
teachers in Gia Lam district, minus those teachers who are not qualified
for the study and did not participate in the study from the first visit at

the school, the study collected The final sample size was 476 teachers
for research objective 1.
2.2.2.2. Sample size in a non-control intervention study
In order to be highly representative and to ensure ethical issues in
the research, the study selected all qualified teachers with voice


8
disorders from 20 schools to participate in the intervention group. In
fact, the sample size of the intervention study is 126 primary school
teachers in Gia Lam district - Hanoi.
2.2.3. Study tools and equipments
2.2.3.1. Cross-sectional Study: Conducted in Primary Schools
- Questionnaire, study medical record; Otolaryngoscope with 0 and
70 degree.
2.2.3.2. Interventional study: Conducted at the Central Hospital of ENT
- Set of questionnaire; Study medical records; Recorder, computer,
PRAAT
Software, Accumulation; Soundproof chamber (Audio test
chamber); laryngeal
Stroboscope
2.2.3.3. Techniques using in interventional study:
* Voice recording and analysis: Voice recording in a soundproof room
* Collect feeling data using the GRBAS scale:
* Laryngeal stroboscopy: Performed at the Department of Audiology
- Central Hospital. Laryngoscopy with Pulsar II (Karl - Storz,
Germany).
2.2.4. Study variable and indicator
2.2.4.1. Cross sectional study
- Group of indicators on the general characteristics of the subjects in

the research
group; Index group on professional characteristics; A group of
indicators describing
the current state VD in the study; Group of indicators related to the
subject's
KAP on voice hygiene.
2.2.4.2. Interventional Study
- Group of indicators related to functional and entity VD; group of
related
Indicators to LPR and comorbid cardiovascular disease; Group of
indicators on treatment effectiveness: combination of medical treatment,
voice hygiene and voice training; Group of indicators related to
compliance and maintenance of training regimens and methods.


9
2.2.5. Study proces
Female teachers of 20 schools

Quantitative interview,
listening to voice assessment

Clinical examination
and endoscopy larynx

Have voice disorders

T0 Stage:
- Step 1: Teachers were explained about the intervention process and agreed to
participate in the study

- Step 2: The teacher goes to the Central Hospital of Cardiology to participate in
the intervention study by appointment (Recording, Experimental examination,
ENT examination)
- Step 3: Teachers are examined, guided for treatment, and applied interventions
(Instructions on voice training, oral hygiene, medical treatment)
- See you again in 6-8 weeks.

T1 stage:
- All teachers are examined and guided for treatment as stage T0
- Re-examination in 3-4 months

T2 stage:
- All teachers are examined and guided for treatment as in stage T1.
- Final evaluation.

Diagram 2.1. Study process diagram
2.2.7. Principles of intervention grouping:
2.2.7.1. Principle: The basic principle in the treatment of VD is to
adjust the pronunciation behavior of teachers based on the program of
oral hygiene and voice training, so all teachers in the intervention study
group will implement these two contents.


10
2.2.7.3.Specific regimen:
- Voice hygiene: Tips in daily life, in using voice to help teachers
give up or limit bad habits for vocal cords.
- Vocal training: Using techniques that affect the vocal apparatus for
the purpose of restoring vocal cord injury and regaining full function of
the vocal cords. Apply the exercise prototype to Mathieson and boone's

functional VD.
- Internal medicine treatment:
+ Treatment of LPR: In the study using Esomeprazole manufactured
by Astra Zeneca, the treatment dose: Esomeprazole 40mg, 1 time / day,
taken in the morning 30 minutes before meals for 6-8 weeks. Combine
PPI treatment with dietary and lifestyle changes.
+ Treatment of ENT diseases: Depending on the disease, GV will
conduct appropriate treatment according to the "Guidelines for
diagnosis and treatment of ENT disease" issued by the Ministry of
Health in 2013.
2.2.8. Data analysis
- Research using Epidata to enter and control data; SPSS 13.0 for data
analysis.
- Statistical algorithms used in data analysis: Sample parameters:
Percentage, mean, standard deviation;Test 2 was used to compare 2
percentages; The t test is used to compare the mean values of two groups of
observations; Evaluation of intervention results based on effectiveness
index.
2.3. Ethical consideration
- The research subjects were informed and fully explained by the
research team about the purpose, requirements and research content so
that they understood and voluntarily participated. Research results on
personal matters are kept confidential.
- Intervention solutions suitable to the content of treatment, care and
improvement of people's health in Vietnam and around the world,
without affecting human health and the environment, have been
accepted by the community.
- Teachers with voice disorder are consulted for treatment.



11
CHAPTER 3
STUDY RESULTS
3.1. The status of female primary school teachers' voice disorders in
terms of function, entity and accompanying ENT diseases.
Table 3.1. Prevalence of voice disorders among female primary
school teachers
Voice disorder (VD)

No.

Rate (%)

Without VD

58

12,18

VD

418

87,82

Total

476

100


Subjects with 1 to more changes in vocal quality or vocal
discomforts through perceptual assessment - subjects with 1 or more
symptoms were counted as having VD. The majority of primary school
teachers have VD, accounting for 87.80%.

Figure 3.1. Rate of VD among female primary school teacher
The majority of primary school teachers have more than 3 functional
symptoms of VD, accounting for 70%.


12
 Relationship between of VD and associated ENT diseases in the
study
Table 3.2. Relationship between voice disorders and ENT diseases
Accompany
Without VD
VD
OR
95% CI
diseases
n = 58
n = 418
(12,18%)
(87,82%)
No ENT diseases
34 (58,62)
198 (47,37)
1
.

.
Allergic rhinitis
6 (10,34)
32 (7,66)
0,91 0,35 2,36
Rhinosinusitis
4 (6,90)
20 (4,78)
0,85 0,27 2,67
Pharyngitis,
5 (8,62)
30 (7,18)
1,03 0,37 2,84
chronic tonsillitis
Laryngopharyngeal
7 (12,07)
123 (29,43) 3,01 1,28 7,08
reflux (LPR)
Other ENT
2 (3,45)
15 (3,59)
1,28 0,28 5,90
diseases
Out of a total of 476 study subjects, 87.8% suffered from VD.
Among the subjects with VD, there were 47.37% of the subjects
without ENT disease, 29.43% of the subjects had LPR, and 7.66% of
the subjects had allergic rhinitis. Subjects with VD had a 3.01-fold
higher risk of laryngopharyngeal reflux (LPR) than those without VD
(OR=3.01, 95% CI, p=0.007).
 Some factors related to VD in female primary school teachers

Table 3.3. The relationship between the number of teaching hours
and the number of symptoms of voice disorders (over 3 symptoms)
0–3
Teaching
>3 symtoms
95% CI
symptoms
OR
n (%)
hours
n (%)
1–5
36 (25,0)
47 (14,16)
1,00
,
,
6–7
92 (63,8)
245 (73,8)
2,04 1,23 3,36
>7
16 (11,1)
40 (12,5)
1,91 0,91 3,99


13
Table 3.3 shows that the group of teachers who teach 6-7 teaching
hours/day have more than 2 times the risk of having more than 3

symptoms of VD than the group of teachers who teach less than 5
hours/day (OR=2.04, 95% CI: 1.23-3.36).
3.2. Evaluating the effectiveness of interventions in the treatment of
VD in primary school teachers
Table 3.4. Intervention methods for study subjects
Intervention method
No.
Rate (%)
Voice training
126
100,0
Vocal hygiene
126
100,0
Surgery
0
0,0
Internal medicine
78
61,9
Of the 126 teachers participating in the study, 100% of the teachers
were intervened with voice training and voice hygiene, 78/126 (61.9%)
teachers received medical intervention at the Central hospital of Ear
Nose Throat. None of the teachers had to perform surgery.
Table 3.5. Prevalence of voice disorders of study subjects
after the examinations
>3
Effect
T0
T1

T2
symptoms
index
Rate of VD
T2 and
n = 476
n = 126 (%) n = 126 (%) (n = 60)
T0
Yes
322 (67,6) 126 (100,0) 82 (65,1) 38 (64,4)
74,4%
No
144 (32,4)
0 (0,0)
44 (34,9) 21 (35,6)
From 476 teachers, this study selected 126 teachers with VD, had at
least 2 examinations and participated in the study. By the second
examination, there were only 82/126 teachers with VD, accounting for
65.1%. By the 3rd re-examinations, after 3-6 months of re-examination,
only 38/60 teachers with VD came to the examination, accounting for
64.4%.


14
 Index group on the effectiveness of combining medical
treatment, voice hygiene and voice training
Table 3.6. Rate of improvement of voice disorders
compared to before intervention according to the GRBAS
receptor scale vowel "a"
T0

T1
T2
Effect
p
index
GRBAS
(anova T2
scale
Mean ± SD Mean ± SD Mean ± SD
test)
and
T0
Grade

4,46 ± 1,32

2,48 ± 1,34 2,15 ± 1,07 < 0,0001 51,7%

Roughness

3,03 ± 1,65

1,37 ± 1,37 1,23 ± 1,11 < 0,0001 59,4%

Breathniess

0,88 ± 0,89

0,24 ± 0,53 0,08 ± 0,28 0,0009 90,9%


Asthenia

0,21 ± 0,44

0,04 ± 0,20 0,02 ± 0,13

Strain

3,91 ± 1,34

2,00 ± 1,25 1,65 ± 1,02 < 0,0001 57,8%

0,99

90,4%

According to the GRBAS perception scale, all indicators related to
the level of voice disorders: Grade, Roghness, Strain have decreased by
more than half. Particularly, the level of breathniess voice decreased
from 0.88 ± 0.89 before the intervention to 0.08 ± 0.28 at the 3rd reexamination. All differences were statistically significant with p<0.05 .
Particularly with Asthenia voice, the improved results were not
statistically significant with p=0.99.


15
Table 3.7. The rate of improvement of voice disorders compared to
before intervention through laryngeal stroboscopy
Lesion
position


Left
vocal
cord

Right
vocal
cord

Type of lesion
Swelling
Congestion
Thick mucus
fibrous granules
Polyp
Without lesion of
mucosa
Swelling
Congestion
Thick mucus
fibrous granules
Polyp
Without lesion of
mucosa

T0
n = 126
(%)
79 (62,7)
17 (13,5)
0 (0,0)

4 (3,2)
3 (2,4)

T1
n = 126
(%)
36 (28,6)
1 (0,8)
0 (0,0)
4 (3,2)
3 (2,4)

T2
n = 60
(%)
22 (36,7)
0 (0,0)
0 (0,0)
1 (1,7)
0 (0,0)

p
T0 &
T1
<0,001
<0,001

p
T0 &
T2

0,001
0,003

0,821
0,483

0,456
0,523

87 (69,0)

108 (85,7)

54 (90,0)

<0,001

0,001

81 (64,3)
17 (13,5)
0 (0,0)
4 (3,2)
0 (0,0)

37 (29,4)
1 (0,8)
0 (0,0)
4 (3,2)
0 (0,0)


22 (36,7)
0 (0,0)
0 (0,0)
1 (1,7)
0 (0,0)

<0,001
<0,001

0,001
0,001

0,821

0,652

88 (69,8)

110 (87,3)

54 (90,0)

<0,001

0,001

More than 62.7% had swelling in the left vocal cord, after the first
intervention, only 28.6% had swelling, but after 3-6 months of the third
examination, the rate of left vocal cord swelling increased to 36.7 %.

Other lesions in the left vocal cord such as fibrous granules, polyps
were different after the intervention, but there was no statistical
significance (p>0.05). The rate of no mucosal damage of the left vocal
cord increased from before the intervention to after the first and second
examination at 69%, 85.7% and 90%, respectively.
With right vocal cords, more than 64.3% had pre-interventional
edema, but after the 1st and 2nd examination, the rate of edema
decreased to 29.4% and 36.7%, respectively. The rate of no damage to
the mucosa of the right vocal cords increased from before the
intervention to after the first and second examination at 69.8%, 87.3%
and 90%, respectively.


16
Table 3.8. Improvement rate of LPR and the accompanying ENT
diseases after interventions
T0
T1
T2
Effect
Comorbidities
index
n=
n=
n=
with diseases
(T2 &
126(%)
126(%)
60(%)

T0)
With LPR
58 (46,03) 17 (13,4)
3 (5,0)
76,0%
Without LPR
68 (53,97) 109 (86,5) 57 (95,0)
With ENT diseases 53 (42,0)
10 (7,9)
2 (3,3)
35,6%
Without ENT
73 (58,0) 116 (92,1) 58 (96,7)
diseases
In the group of subjects with LPR, the intervention effect was very
clear after each examination, before the intervention, 46.3% of the
subjects had LPR, after the intervention until the 1st visit, only 13.4%
of the subjects and By the 3rd visit, only 5% of subjects had LPR. In the
group without LPR, the effectiveness of the intervention also improved
significantly, before the intervention there were 53.97% of the subjects,
but at the 2nd visit, the number of people without LPR increased by
more than 30% (86.5%), By the third visit, up to 95% of subjects did
not have LPR reflux. There were 42% of teachers before the
intervention had VD accompanied by mental retardation, but by the 3rd
visit, only 3.3% of teachers had comorbidities. The results related to the
treatment effect through the visits were statistically significant with
p<0.05.


17

Table 3.9. Effective treatment of other ENT diseases through 3 visits
T0

T1

T2

n (%)

n (%)

n (%)

Allergic rhinitis

21 (16,7)

9 (7,1)

4 (6,7)

0,027

Pharyngitis, chronic tonsillitis

29 (23,0)

18 (14,3)

5 (8,3)


0,028

3 (2,4)

1 (0,8)

1 (1,67)

0,604

Characteristics

Chronic rhinosinusitis

p(2 test)

Efficacy of treatment of cardiovascular diseases associated with VD
in the study subjects was also greatly improved. Before treatment,
16.7% of teachers had allergic rhinitis, after treatment, the disease was
controlled and only 6.7% had symptoms at the 3rd visit (p<0.05).
Before the study, the rate of teachers suffering from pharyngitis and
chronic tonsillitis was 23%, but after the intervention until the 3rd visit,
it was only 8.3% (p<0.05).


Index group of adherence with interventions through visits

Table 3.10. Level of adherence to intervention therapy through visits
T1


T2

n = 126 (%)

n = 60 (%)

Fully adherence

79 (62,7)

33 (55,0)

Partly adherence

47 (37,3)

22 (37,0)

0 (0,0)

5 (8,0)

Adhere to daily exercise

No adherence

p
(com.
test )

0,004

The percentage of subjects adherence with exercises about doing the
exercises correctly was from 62.69% at the 2nd visit and 55% at the 3rd
visit, not at the 3rd visit was 8%, but the difference was statistical
significance with p=0.004.


18
CHAPTER 4
DISCUSSION
4.1. The status of female primary school teachers' voice disorders in
terms of function, entity and accompanying ENT diseases
4.1.1. Situation with symptoms of voice disorders
Out of a total of 476 primary school teachers interviewed, 87.8%
suffered from VD. The prevalence of more than 3 symptoms of VD is
70%, of which the most common symptoms are intermittent voice loss
(64%); talk quickly (60.1%); shortness of breath when speaking
(57.9%) and hoarse voice (55.8%). In our country at present, there are
not many reports and specific investigations on VD in female primary
school teachers, a study by Tran Duy Ninh in 2010 on 416 primary
school teachers in Thai Nguyen city showed that the prevalence of
mental VD was 76.2% and 46.88% of teachers have more than 3
symptoms. In the world, there have been many studies proving that
teachers are at high risk of having schizophrenia. A study by author
Luce in 2014 on 157 primary school teachers (98% female) in Italy
showed that 68.7% had VD and had different symptoms of laryngeal
disease. The above results show that there is a difference in the
prevalence of poverty among regions in the world, which shows that the
problem related to VD is quite common and serious.

 Rate of injury to the larynx of female primary school teachers in
Gia Lam district, Hanoi
The results of this study showed that muscle tension voice disorder
was the most common cause in the group of teachers with VD with the
rate of 78.7%. In this study, other laryngeal lesions had a lower rate:
chronic laryngitis was 17.46%; vocal cord nodules (1.91%); vocal cord
polyps (0.96%) and some other vocal cord diseases (0.96%). The results
of our study with the group of VD with lesions in the larynx are also
consistent with the studies of Tran Duy Ninh on primary school
teachers in Thai Nguyen city: vocal cord thickening (10.82%); vocal
cord nodules (2.88%). Pham Thi Ngoc on primary school teacher Dong
Anh district, Hanoi: Vocal cord thickening (15.77%); vocal cord
nodules (4.35%); vocal cord polyps (0.67%). Particularly, the rate of


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VD in this study was 78.7% and much higher than that of two authors
Tran Duy Ninh (8.17%) and Pham Thi Ngoc (9.60%), the difference
may be Due to the diagnostic criteria, the data collection method of the
studies is different
4.1.2. ENT diseases associated with VD status in the female primary
school teacher group.
The results of our study showed that, the group of teachers with VD
had the rate of comorbidities of ENT accounted for 52.63%, of which
LPR accounted for 29.43%; Nasal sinus disease accounted for 12.44%.
LPR rate in this study is lower than other studies in the world. A study
by Brent and colleagues on 39 patients with laryngeal irritation
syndrome found that more than 90% had gastroesophageal reflux
disease.
4.1.3. Some risk factors related to VD of female primary school

teacher of Gia Lam, Hanoi.
The profession of a teacher is a profession that requires the use of
voice with great intensity and continuously for a long time. The use of
voice with such intensity is one of the causes/risk factors leading to VD.
This study found a statistically significant relationship between the
number of lessons in a day and the incidence of more than 3 symptoms
of VD, the group of teachers with 6-7 teaching hours/day at risk of
having more than 3 symptoms. symptoms of VD was 2.04 times higher
than that of the group of teachers who only lectured for less than 5
teaching hours/day (OR=2.04, 95%CI 1.23-3.36).
4.2. Evaluation of results of voice disorder interventions in female
primary school teachers in Gia Lam district - Hanoi
Our study uses indirect and direct methods of pronunciation
behavior modification (voice hygiene and voice training) for all
teachers in the intervention study. Voice hygiene is advice to limit bad
habits for the throat and larynx, while voice training is the technique
that affects the vocal apparatus for the purpose of restoring damaged
vocal cord mucosa and regaining full function. These techniques aim to
adjust the pronunciation behavior of teachers. In the world, there are
many studies applying voice training method that have brought very
positive results. In this study, we applied vocal exercises including 4


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main exercises: auxiliary breathing exercises (15 minutes), Yawn-sigh
exercises (10 minutes); exercises according to the Humming method
(15 minutes); breathing exercises (10 minutes).
4.2.1. Group of indicators related to functional and entity RLGN
In this intervention study, we conducted the intervention with voice
hygiene and voice training for all 126 female teachers selected. The

study results showed that there was an improvement in VD (34.9%
ended of VD after the first intervention) and the severity of VD changed
through subjective and objective assessment: symptoms level. The
severity and moderate symtoms of VD both decreased. Studies on voice
hygiene and voice training have been proven effective in many
countries around the world. Research by Liu et al in 2020 on 34 female
teachers in China was divided into 2 groups, including 16 teachers
participating in the treatment of both voice training and voice hygiene,
18 female teachers participating in the certificate group. voice hygiene.
The results showed that the group that combined voice hygiene and
voice training had an improvement in all research indicators such as
Voice Handicap Index (VHI), GRBAS, voice quality, functional and
physical problems. In the group that only applied voice hygiene
measures, the effectiveness of improving indicators related to VD was
not clear.
4.2.2. Group of indicators related to LPR syndrome and ENT diseaseS
In our intervention study, 46.03% of subjects had LPR reflux
syndrome, less than those without LPR (53.97%). The proportion of
subjects with concomitant cardiovascular disease accounted for 42% of
the total study subjects; 16.7% of subjects had allergic rhinitis, 23% of
subjects had pharyngitis, chronic tonsillitis. Only 2.38% of subjects had
chronic rhinosinusitis. Accompanying ENT diseases will be treated
according to the guidelines of the Ministry of Health. Through this
study, we see the effectiveness of medical treatment through the
improvement of symptoms of diseases related to ENT. Diseases with a
marked reduction rate such as Allergic Rhinitis decreased from 16.7%
before the intervention to 6.7% in the 3rd visit. Pharyngitis, chronic
tonsillitis decreased from 23% before the intervention to 8.3% at the 3rd
visit. In our study, the effectiveness of interventions with voice hygiene



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and voice exercises is also very clear. Before the study, 46.3% of
female teachers had LPR, but 6-8 weeks after the intervention until the
2nd visit, only 13.4% of female teachers have LPR. By the 3rd visit,
only 5% of teachers had LPR. This statistically significant result (with
p<0.001) clearly shows the effectiveness of the voice hygiene and voice
training interventions in this study with patients with voice disorder
accompanied by LPR.
The rate of improvement of VD compared with before intervention
according to the RSI and RSF scale in patients with LPR was very clear
in our intervention study. Before the intervention, the RSI score was
17.00 ± 3.76, 13 points higher than the average score, but after 6-8
weeks of intervention, re-examination at the 2nd visit, the score was
only 8.76 ± 2. 3.77 and by the 3rd visit it was only 5.73 ± 3.23.
4.2.3. The group of indicators on the effectiveness of the
combination of medical treatment, voice hygiene and voice training
Improved VD according to the GRBAS scale
One of the most widely used perceptual scales in the world is the
GRBAS, introduced and recommended for use by the Speech
Function Exploration Committee of the Japan Acoustics Association.
This is considered a voice rating scale with clearly defined
parameters, very suitable for common pathologies in the larynx. The
parameters of this scale include G (grade), R(roughness), B
(breathiness), A (asthenia), and S (strain). In our intervention study,
according to the GRBAS sensing scale, all indicators related to the
level (G), rough voice (R), tense voice (S) were reduced by more
than half (p). <0.05). Particularly, the level of breathing voice
decreased from 0.88 ± 0.89 before the intervention to 0.08 ± 0.28 at
the 3rd visit. All differences were statistically significant with

p<0.05 .
Improve sound quality through examinations
In our study, the level of improvement in sound quality was very
clear. The parameters F0 (Hz), Jitter parameters (µs), HNR
parameters (dB) ) in both the vowels /a/ and /i/ have markedly
improved, similar to the research of Nguyen Duy Positive. Our
results of improving voice quality are similar to that of Pereira's


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study conducted on 90 teachers with VD, the results also show that
voice hygiene measures significantly improve the parameters F0,
Jitter and even LPR syndrome.
Improved voice disorders by laryngeal stroboscopy
In our intervention study performed on 126 female teachers,
laryngoscopy before intervention had 62.7% swelling in the left
vocal cord, 64.3% in the right vocal cord after the intervention. 1,
only 28.6% of the left vocal cords and 29.4% of the right vocal cords
remained. But after 3-4 months of 3rd examination, the percentage
of left and right vocal cords was increased compared to the 2nd visit,
accounting for 36.7% of the total number of female teachers who
visited the 3rd time. maybe because the number of 3rd visit to the
doctor is only 60 female teachers, most of them still have problems
related to VD and diseases of the ear, nose and throat, so they just
came back for a checkup, possibly because of a medical condition.
Ear, nose and throat infections are newly acquired, so the rate of
swelling has also increased.
4.2.4. Group of indicators related to adherence and maintenance of
training regimens and methods
In this intervention study, female teachers' adherence to the

exercises was generally unstable. The degree of compliance with
exercises on all days of the week at the 2nd visit reached 82.5%, but
at the 3rd visit, it was reduced by more than half to only 36.7% of
the subjects. However, this can be understood in the voice training
instruction, if when the intervention results are better and the teacher
performs the exercises well, then it can be done every other day at a
later stage, if in the interval of practicing every other day. If there
are signs of increased VD, teachers need to be examined, reevaluated and adjusted exercises. There are many reasons leading to
non-compliance with the treatment of VD in general and vocal
training in particular such as teachers do not have the right time and
space, 38.30% of teachers said that the exercises were long.