1

COMPARING THE HEARING THRESHOLD

BETWEEN POSTERIOR AURICULAR MUSCLE

RESPONSE (PAMR) AND PURE TONE

AUDIOMETRY (PTA) IN IMPAIRED HEARING

INDIVIDUALS

By

DR AIFAA BINTI ABDUL MANAN

Dissertation Submitted in Partial Fulfillment of the

Requirements for the Degree of Master of Medicine

(Otorhinolarnyngology-Head and Neck Surgery)

UNIVERSITI SAINS MALAYSIA

2015

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ACKNOWLEDGEMENT

Thanks to Allah, the Most Merciful and Most Grateful and with His blessings has allowed

me to complete this study without much difficulty. I would like to express my deepest

gratitude and appreciation to my supervisors, Dr Nik Adilah binti Nik Othman, Dr Mohd

Normani bin Zakaria and Prof Madya Dr Rosdan Salim who has inspired me and giving me

unrelentless support and guidance in completing this dissertation. Their constructive

criticism and valuable guidance has helped me through the hassle and obstacles during

field works and writing up the study.

My sincere appreciation to Prof Baharuddin Abdullah, the Head of Department ORL-HNS,

USM for his invaluable advises and support throughout the year. Special thanks to Mrs

Rosninda, the audiologist, for her patience and hard work. I am also indebted to all my

fellow colleagues and all staffs of Otorhinolaryngology , School of Medical Science and

unit of Audiology Unit Hospital USM, past and present; for rendering generous support

and willing assistance in contributing to this study.

My warmest thanks also go to Dr Najib Majdi bin Yaacob, lecturer from Biostatistic

department for helping me with the statistical analysis.

Finally, I have received enormous continuous support, understanding and patience from my

beloved husband, Dr Mohd Sufian Ardi, our child; Muhammad Al Fateh, my parents and

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the rest of my family for their fullest love and unconditional support, understanding and

cooperation throughout my postgraduate study. Without their support, this study would not

have been successful and memorable.

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TABLE OF CONTENTS

CONTENTS PAGE

ACKNOWLEGEMENT ii

TABLE OF CONTENTS iv

LIST OF ABBREVIATIONS vii

LIST OF FIGURES ix

LIST OF TABLES xi

ABSTRAK xii

ABSTRACT xv

CHAPTER 1: INTRODUCTION AND LITERATURE REVIEW

1.1 Introduction 1

1.2 Anatomy of the ear 3

1.2.1 The external ear 3

1.2.2 The middle ear 4

1.2.3 The inner ear 6

1.3 The overview of physiology of hearing 7

1.4 Definition of hearing loss 9

1.5 Type of hearing loss 10

1.6 Degree of hearing loss 11

1.7 Hearing assessments 13

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1.7.1 Subjective & objective test of hearing assessments 13

1.8 Posterior auricular muscle response (PAMR) 18

1.9 Rationale for this study 25

CHAPTER 2: OBJECTIVES OF STUDY

2.1 General objective 26

2.2 Specific objectives 26

CHAPTER 3: METHODOLOGY

3.1 Study design 27

3.2 Study population 27

3.3 Study method 27

3.4 Selection criteria 28

3.4.1 Inclusion criteria 28

3.4.2 Exclusion criteria 28

3.5 Sample size calculations 29

3.6 Ethical issues 30

3.7 Study procedure 30

3.8 PAMR method 31

3.8.1 PAMR protocol 31

3.8.2 PAMR setup and subject preparation 32

3.8.3 Interpretation of PAMR 32

3.9 Flow chart 35

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3.10 Research materials 36

CHAPTER 4: RESULTS

4.1 General 47

4.2 Age distribution 47

4.3 Gender distribution 48

4.4 Ethnic distribution 49

4.5 Estimation and comparison of mean hearing threshold in cochlear

hearing loss and CHL using PAMR and PTA

50

4.6 Correction factor of hearing threshold in cochlear hearing loss and CHL

using PAMR and PTA

52

4.7 Correlation of hearing threshold for cochlear hearing loss and CHL using

PAMR and PTA

54

4.8 Comparison of correction factor in between cochlear hearing loss and

CHL

60

CHAPTER 5:DISCUSSION

5.1 Demographic data 61

5.2 Comparing of PAMR and PTA findings in cochlear hearing los 62

5.3 Comparing of PAMR and PTA findings in Conductive Hearing Loss 66

5.4 Comparing correction value between cochlear hearing loss and CHL 67

CHAPTER 6: CONCLUSION 68

CHAPTER 7: LIMITATIONS AND RECOMMENDATIONS 69

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REFERENCES 71

APPENDICES 76

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LIST OF ABBREVIATIONS

AABR Automated auditory brainstem response

ABR Auditory brainstem response

AEP Auditory evoked potential

BAER Brainstem auditory evoked response

BOA Behavioural observation audiometry

CHL Conductive hearing loss

CM Cochlear microphonic

dB Decibel

dB HL Decibel hearing loss

dB nHL Decibel normal hearing loss

DT Distraction test

EAC External auditory canal

Hz Hertz

kHz Kilo Hertz

MHL Mixed hearing loss

OAEs Otoacoustic emissions

OHCs Outer hair cells

P-audio Play audiometry

PAM Posterior auricular muscle

PAMR Posterior auricular muscle response

PTA Pure tone audiometry

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SD Standard deviation

SNHL Sensorineural hearing loss

USM Universiti Sains Malaysia

VRA Visual reinforcement audiometry

VEMP Vestibular evoked potential

WHO World Health Organization

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LIST OF FIGURES PAGE

Figure 1.1 Pinna 3

Figure 1.2 Structures in the middle ear 4

Figure 1.3 Electrodes placement in PAMR 19

Figure 3.1 Sample of PAMR waves 34

Figure 3.2 Flow chart of study 35

Figure 3.3 Sound proof room 36

Figure 3.4 Welch Allyn® otoscope 37

Figure 3.5 Tympanometer (Interacoustic Immitence Audiometer) 38

Figure 3.6 Grason-Stadler GSI 61® Clinical Two-channel

audiometer

39

Figure 3.7 Bio-logic Navigator Pro® AEP system 40

Figure 3.8 TDH-39 headphone 41

Figure 3.9 Dell Vosto® 1400 notebook 42

Figure 3.10 Ag/AgCI electrode (Ambu Blue Sensor N) 43

Figure 3.11 Electrodes placement in PAMR procedure 44

Figure 3.12 Fixed point on the wall 45

Figure 3.13 70 0

eye turn to side of stimulus 46

Figure 4.1 Gender distribution of subjects 48

Figure 4.2 Ethnic distribution of subjects 49

Figure 4.3 Correlation between PAMR and PTA threshold at 55

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500 Hz in Cochlear hearing loss

Figure 4.4 Correlation between PAMR and PTA threshold at

1000 Hz in Cochlear hearing loss

55

Figure 4.5 Correlation between PAMR and PTA threshold at

2000 Hz in Cochlear hearing loss

56

Figure 4.6 Correlation between PAMR and PTA threshold at

4000 Hz in Cochlear hearing loss

56

Figure 4.7 Correlation between PAMR and PTA threshold at

500 Hz in CHL

58

Figure 4.8 Correlation between PAMR and PTA threshold at

1000 Hz in CHL

58

Figure 4.9 Correlation between PAMR and PTA threshold at

2000 Hz in CHL

59

Figure 4.10 Correlation between PAMR and PTA threshold at

4000 Hz in CHL

59

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LIST OF TABLES PAGE

Table 1.1 Degree of hearing loss according to WHO classification 11

Table 1.2 Degree of hearing loss used in Hospital Universiti Sains

Malaysia

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Table 4.1 Age distribution of subjects 46

Table 4.2 Comparing mean threshold difference between PAMR

and PTA in cochlear hearing loss

50

Table 4.3 Comparing mean threshold difference between PAMR

and PTA in CHL

51

Table 4.4 The correction factors (dB HL) between PAMR and PTA

at all frequencies in cochlear hearing loss

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Table 4.5 The correction factors (dB HL) between PAMR and PTA

at all frequencies in CHL

53

Table 4.6 Correlation between PAMR and PTA in cochlear hearing

loss

54

Table 4.7 Correlation between PAMR and PTA in CHL 57

Table 4.8 T-test to compare correction value between SNHL and

CHL

60

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ABSTRAK

BAHASA MALAYSIA VERSION

TAJUK KAJIAN:

MEMBANDINGKAN NILAI AMBANG PENDENGARAN DALAM KALANGAN

SUBJEK DEWASA YANG MEMPUNYAI PENDENGARAN ABNORMAL

MENGGUNAKAN UJIAN RESPON OTOT BELAKANG TELINGA (PAMR) DENGAN

UJIAN AUDOMETRI NADA TULEN ( PTA)

PAMR adalah merupakan ujian objektif elektrofisiologi untuk menentukan ambang

pendengaran. Ia adalah merupakan respons otot koklea yang dirangsang dengan

menggunakan nada bunyi klik atau nada bunyi pecah dan respon PAMR ini diukur sebagai

perbezaan rangsangan di antara otot belakang telinga and cuping telinga.

OBJEKTIF

Tujuan kajian ini dijalankan adalah untuk menentukan dan membandingkan nilai ambang

pendengaran seseorang dewasa yang mempunyai kehilangan pendengaran jenis sensori

dan kehilangan pendengaran jenis konduktif dengan menggunakan ujian PTA dan PAMR.

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Seterusnya, nilai ambang pendengaran PTA dan PAMR bagi kedua-dua kumpulan hilang

pendengaran ini dibandingkan bagi mendapatkan faktor pembetulan.

KAEDAH KAJIAN

Kajian ini merupakan kajian keratan rentas yang dijalankan di Klinik Audiologi, Hospital

USM bermula dari 1hb Jun 2013 sehingga 31hb Mei 2014. Sebanyak 38 dewasa (n = 76

telinga) yang memenuhi kriteria dan berumur antara 18 hingga 60 tahun telah dipilih.

Kemudian, subjek-subjek ini diperiksa menggunakan otoskop, ujian tympanogram dan

ujian PTA. Ujian pereputan nada dilakukan untuk pesakit dengan kehilangan pendengaran

sensorineural untuk menunjukkan kehilangan pendengaran retrokoklear. Pesakit dengan

ujian pereputan nada normal akan meneruskan PAMR.

Seterusnya, ujian PAMR dilakukan dengan meletakkan elektrod positif pada cuping

telinga, elektrod negatif pada bahagian otot belakang telinga dan elektrod rujukan pada

bahagian dahi. Kemudian, ujian PAMR ini dilakukan pada frekuensi 500, 1000, 2000 dan

4000 Hz dengan menggunakan bunyi nada pecah. Subjek diarahkan melihat pada arah 700

ke tepi mata mengikut arah rangsangan bunyi yang dibagi dan graf dirakamkan.

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KEPUTUSAN

Nilai ambang PAMR adalah lebih tinggi berbanding dengan nilai ambang PTA. Oleh

kerana terdapat perbezaan di antara nilai ambang PAMR dan PTA, faktor pembetulan dapat

ditentukan. Faktor-faktor pembetulan menurun dengan peningkatan frekuensi. Dalam

pesakit hilang pendengaran jenis sensori, faktor pembetulan adalah 26.29, 19.00, 16.00,

13.00 untuk 500, 1000, 2000 dan 4000 Hz . Dalam pesakit hilang pendengaran jenis

konduktif, faktor pembetulan adalah 20.29, 18.68, 14.12, 12.06 untuk 500, 1000, 2000 dan

4000 Hz .

KESIMPULAN

PAMR boleh digunakan sebagai salah satu ujian objektif bagi menentukan nilai ambang

pendengaran seseorang dengan terbuktinya semua subjek dalam kajian ini menunjukkan

graf PAMR direkod apabila mata subjek mengiring ke tepi mengikut rangsangan bunyi.

Walau bagaimanapun, disebabkan terdapat perbezaan di antara nilai ambang pendengaran

PAMR dibandingkan dengan PTA, faktor pembetulan telah ditentukan dan faktor

pembetulan ini hendaklah ditambah pada nilai ambang pendengaran PAMR seseorang bagi

menentukan nilai ambang pendengaran PTAnya.

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ABSTRACT

ENGLISH VERSION

TITLE: COMPARING THE HEARING THRESHOLD BETWEEN POSTERIOR

AURICULAR MUSCLE RESPONSE (PAMR) AND PURE TONE

AUDIOMETRY (PTA) IN IMPAIRED HEARING INDIVIDUALS

Posterior Auricular Muscle Response (PAMR) is an objective electrophysiological test to

determine hearing thresholds. It is a cochlear myogenic response evoked by a click or tone

burst stimuli and the response is measured as potential difference between posterior

auricular muscle and rear of ear pinna.

OBJECTIVE

The aim of this study is to estimate and to compare the mean hearing thresholds in cochlear

hearing loss and CHL using PAMR and PTA. Then, the hearing thresholds of PAMR and

PTA in cochlear hearing loss and CHL patient are compared in order to determine the

correction factors.

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METHOD

This is a cross sectional study conducted at Audiology Clinic, Hospital USM starting from

1st June 2013 until 31

st May 2014. It comprised of 76 volunteered subjects and aged

ranging between 18 to 60 years.

All patients were examined using otoscopy, tympanometry and then PTA. Tone decay test

was done for patient with sensorineural hearing loss to exclude retrocochlear hearing loss.

Subject with normal tone decay test will proceed with PAMR. Finally, the PAMR were

performed by placing the positive electrode at the ear lobule, negative electrode at the

posterior auricular muscle while the reference electrode was placed at the forehead. This

PAMR were measured at frequencies 500, 1000, 2000 and 4000 Hz using tone burst stimuli

and the subject was asked to make 70⁰ lateral eye turned to side of stimulus when the

stimulus was being presented and the waves recorded.

RESULT

The PAMR thresholds noted were higher compared to the PTA thresholds. As there were

differences in hearing thresholds between PAMR and PTA, the correction factors were

determined. The correction factors decreased with increased in frequencies. In cochlear

hearing loss patients, the correction factors were 26.29, 19.00, 16.00, 13.00 for 500, 1000,

2000 and 4000 Hz respectively. In CHL patients, the correction factors were 20.29, 18.68,

14.12, 12.06 for 500, 1000, 2000 and 4000 Hz respectively.

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CONCLUSION

PAMR can be used as one of objective tests to determine hearing thresholds since all the

subjects had recordable PAMR waves with eye turned position. However, because of

difference in PAMR thresholds compared to PTA, the correction factors should be applied

to PAMR threshold in order to estimate PTA thresholds.

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CHAPTER 1

INTRODUCTION

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1.0 INTRODUCTION AND LITERATURE REVIEW

1.1 Introduction

The most common form of sensory impairment all over the world is hearing loss. The

World Health Organization (WHO) estimated that in 2008 more than 360 million people

have disabling hearing loss which represents 5.3% of the world population. Eighty per cent

of these people living in low- or middle-income countries. The highest prevalence of

hearing impairment in both adult and children are in South East Asia and sub-Saharan

Africa. This can be explained by the high rates of infections such as chronic otitis media,

meningitis, excessive noise, ototoxic drugs and ageing populations in developing countries

(Duthey, 2013).

Hearing impairment affects all age group. From 2003 till 2004, 29 million Americans

which represent 16.1% of the adults had speech frequency hearing loss. In the youngest age

group from 20 to 29 years old, 8.5% exhibited hearing loss and the prevalence seems to be

increasing among this age group(Agrawal et al., 2008).

Hearing loss is an important public health concern with economic and society burden.

Hearing impairment in infant and children will cause delay in education and

communication development(Davis et al., 2001). The impact of hearing impairment in

childhood is devastating. Poor language development cause negative impact on literacy

skills, academic achievements and subsequently income and socioeconomic status.

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Therefore, the main aim is for early diagnosis of hearing loss and hearing rehabilitation can

be established(Proops and Acharya, 2009).

Majority of the hearing loss and ear diseases are avoidable and reversible if proper

screening and management could be carried out at initial stage of identification. World

Health Organization (WHO), has set up a program for the Prevention of Deafness and

Hearing Impairment aiming at the development of technology, educating proper or

appropriate hearing care and protection, improving the services in order to prevent deafness

and hearing impairment. The prevention program includes primary, secondary and tertiary

prevention. In primary prevention, the aim is to prevent any risk factors that could impair

the hearing status and condition of the ear itself. The secondary prevention aim is to

prevent an already impaired hearing status from progressing to a disability. Lastly, the

tertiary prevention aims at preventing disability progressing to a handicap and at the same

time providing rehabilitation to the patients.(Hinchcliffe, 1997)

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1.2 Anatomy of the ear

The ear can be divided into three parts; the external ear, the middle ear and the inner ear.

The external and middle ears are concerned primarily with the transmission of sound. The

inner ear functions both as the organ of hearing and as part of the balance system of the

body.

1.2.1 The external ear

The external ear consists of pinna, external auditory canal (EAC) and tympanic membrane.

Pinna is also known as auricle. It is composed of thin plate of yellow cartilage which is

covered with skin except its lobule. It is connected to surrounding parts by ligaments and

muscles. There are various elevations and depressions on lateral aspects of pinna as seen

below (Figure 1.1):-

Figure 1.1: Pinna (Adapted from http://sonoworld.com/images/FetusItemImages/article-

images/face_and_neck/ear_anu_patil_images/ear_anatomy.gif)

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The EAC extends from concha of auricle to tympanic membrane. It measures about 2.4 cm

length. It is divided into two parts which are cartilaginous part and bony part. The EAC

ends at the tympanic membrane. The tympanic membrane is a thin and forms a translucent

partition between the EAC and middle ear. It consists of 2 parts; pars tensa and pars

flaccida.

1.2.2 The middle ear

Figure 1.2: Structures in the middle ear (adapted from

http://droualb.faculty.mjc.edu/Lecture%20Notes/Unit%205/special_senses%20Spring%20

2007%20with%20figures.htm)

Middle ear is a narrow air-filled space situated in the petrous part of temporal bone

between the external ear and internal ear. This region includes eustachian tube, tympanic

cavity and mastoid air cells system (Figure 1.2). The tympanic cavity can be described as a

six-sided box with four walls, a roof and a floor. It contains three ossicles; malleus, incus

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and stapes, two muscles (stapedius and tensor tympani muscle) and two nerves (chorda

tympani nerve and tympanic plexus of nerves).

The roof of the cavity is formed by thin plate of bone. The floor separates the cavity from

the bulb of the internal jugular vein. The anterior wall has two openings. The upper portion

lies the canal for the tensor tympani muscle, the lower portion is the auditory tube. The

posterior wall is wider above than below and has its opening to mastoid antrum via aditus

at superior region. Fossa incudis is a depression below aditus. It houses the short process

of incus. Just below it is the pyramid. It is a conical bony projection located in between the

junction of medial and posterior wall. It has an opening at the apex, for stapedius tendon

and nerve.

Lateral to the pyramid is the posterior cannaliculus, which is an opening for chorda

tympani to enter the middle ear cavity. Deep to the pyramid is a depression, the sinus

tympani. Facial recess is lateral to sinus tympani and bounded laterally by chorda tympani,

medially by pyramid and vertical part of facial nerve and superiorly by fossa incudis.

Facial recess is an important surgical landmark because we can go through it into the

middle ear without disturbing posterior meatal wall. Sinus tympani is one of hidden area

for cholesteatoma.

The lateral wall formed mainly by the tympanic membrane and attic. The medial wall of

middle ear cavity separates the tympanic cavity from inner ear. Its surface has several

prominent features and two openings. Promontory is a rounded elevation occupying the