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Hörselvård i Kenya; en regional
fältstudie
Hearing health care in Kenya; a
regional field study
Institutionen för neurobiologi, vårdvetenskap och samhälle
Masterprogrammet i klinisk medicinsk vetenskap
Huvudämnet klinisk medicinsk vetenskap
Examensarbete masternivå, 30 högskolepoäng
Vårterminen 2014
Author: Satu Turunen-Taheri
Supervisors: Ann-Christin Johnson, Department of Clinical Sciences, Intervention and
Technology, Section of Audiology and
Lena Wettergren, Department of Neurobiology, Care Sciences and Society, Karolinska
Institutet
Co-supervisor: De Wet Swanepoel, Department of Communication Pathology, University of
Pretoria, South Africa
Examinerande lärare: Torkel Falkenberg, Institutionen för neurobiologi, vårdvetenskap och
samhälle, Karolinska Institutet
2
Institutionen för neurobiologi, vårdvetenskap och samhälle
Master's program In Clinical Medical Sciences
Major: Clinical Medical Sciences
Master's level, 30 hp
Spring term 2014
Hearing health care in Kenya; a regional
field study
Abstract
The overall aims of this study were to describe hearing health care and
to evaluate a method for tele-audiology in a hearing clinic in Nyeri in Kenya. The study
design was a field study with quantitative approach using consecutive sampling of patients
visiting the hearing clinic. Questionnaires were used to identify the amount of visitors, the
prevalence of hearing loss, tinnitus, ear diseases and malaria. In addition, hearing tests of
patients were gathered during a four week period. The results of traditional hearing
measurements with pure tone audiometry were compared to that of a new tele-audiology
device, Kuduwave, to validate this tele-audiology method under field conditions. Also, the
tele-audiology method was tested in a pilot study by doing a hearing test at a distance.
Eighty patients were included in this study. Thirty-five out of 54 adult patients had tinnitus.
Forty patients received malaria medication and 37 patients had hearing aids. Comparative
results between pure tone audiometry and Kuduwave in eleven patients showed significant
differences on frequencies 250-2000 Hz on the right ear and 250 Hz and 1000 Hz on the left
ear. Positive development of the hearing health care in the clinic was detected.
A field study is an opportunity to get close to the population to be studied. Tinnitus seemed to
be a common symptom and about 50% of patients in this study had a history of malaria. Tele-
audiology offers new opportunities in hearing health care.
3
Institutionen för neurobiologi, vårdvetenskap och samhälle
Masterprogrammet i klinisk medicinsk vetenskap
Huvudämnet klinisk medicinsk vetenskap
Examensarbete masternivå, 30 högskolepoäng
Vårterminen 2014
Hörselvård i Kenya; en regional fältstudie
Sammanfattning
Det övergripande målet för denna studie var att beskriva en kännetecknande patientens
hörselvård och utvärdera en tele-audiologi metod på en hörselklinik i Nyeri i Kenya.
Designen för studien var en fältstudie med kvantitativ ansats som använde konsekutiv
stickprov av patienter som besökte hörselkliniken. Frågeformulär användes för att identifiera
mängden besökande, förekomsten av hörselnedsättning, tinnitus öronsjukdomar och malaria.
Hörseltester av patienter samlades under en fyraveckors period. Resultaten av traditionella
hörselmätningar med tonaudiometri jämfördes med en ny tele-audiology anordning,
Kuduwave, för att validera denna tele-audiologiska metod under fältförhållanden.
Åttio patienter ingick i denna studie. Trettiofem av 54 vuxna patienter hade tinnitus. Fyrtio
patienter hade fått läkemedel mot malaria och 37 patienter hade hörapparater. Jämförande
resultat mellan tonaudiometri och Kuduwave med elva patienter visade signifikanta skillnader
på frekvenserna 250-2000 Hz på höger öra och 250 Hz och 1000 Hz på vänster öra. Positiv
utveckling av hörselvården i kliniken upptäcktes.
En fältstudie är en möjlighet att komma nära befolkningen som skall studeras. Tinnitus
verkade vara ett vanligt symtom och cirka 50% av patienterna i denna studie hade haft
malaria.Tele-audiologin erbjuder nya möjligheter för hörselvården.
4
What is known on this topic?
which 9 % are children. Around 10-15 % of adults in high-income countries are
diagnosed with tinnitus.
Hearing clinics are scarce in Kenya and there is a lack of skilled audiologist as
in many other developing countries which make it difficult for patients with
hearing problems to receive adequate care. Foreign aid project has been known
to help the situation.
Tele-health and tele-audiology use telecommunication in health care services.
This is a new method, which needs more validation under field conditions.
What this paper adds?
In this study, of 65 % of adult patients complaining of tinnitus, 94 % had
hearing impairment of which 54 % had a history of medically treated malaria
according to self-reported questionnaire. These findings acknowledge previous
reports about common causes of tinnitus such as age, noise induced hearing loss
and ototoxic drugs.
Although the conditions by which qualified hearing health care in rural areas of
a low income country in Africa is not always clear, the Kenyan hearing health
care has been developed in recent years. A hearing clinic in Nyeri was started in
2003 by the Kenya Ear Foundation with help of a Swedish financed aid project
and the clinic now manufactures its own hearing molds and has a well-
functioning hearing screening program for both newborn and school children.
Tele-audiology has started in Kenya and offers new opportunities in hearing
health care services including diagnosis of hearing impairment to areas that
otherwise are difficult to reach, especially in low income countries. This study
offers a limited validation under field conditions of this new method as a pilot
testing of tele-audiology method.
5
Index
What is known on this topic? ............................................................................................... 4
What this paper adds? ........................................................................................................... 4
1. Background ......................................................................................................................... 6
1.1. Hearing system’s anatomy and physiology ........................................................... 6
1.2. Hearing loss .................................................................................................................. 8
1.3. Hearing loss in a global perspective ..................................................................... 10
1.3.1 Malaria .................................................................................................................. 10
1.4. Tinnitus ....................................................................................................................... 10
1.5. Audiometry ................................................................................................................ 11
1.6. Tele-audiology. The Kuduwave audiometer ....................................................... 12
1.7. Facts about Kenya, development and hearing health care in Kenya .............. 13
1.7.1. The hearing clinic in Nyeri ............................................................................... 13
1.8. The aims and research questions .......................................................................... 14
1.8.1. Specific research questions ............................................................................. 14
2. Materials and methods .................................................................................................... 15
2.1. Design and approach ................................................................................................ 15
2.2. Samples ....................................................................................................................... 15
2.3. Data collection ........................................................................................................... 16
2.4. Data analysis .............................................................................................................. 16
3. Ethical considerations ..................................................................................................... 16
4. Results ................................................................................................................................ 17
5. Discussion .......................................................................................................................... 17
References.............................................................................................................................. 21
Manuscript ............................................................................................................................. 26
Appendix ................................................................................................................................ 26
Appendix I .......................................................................................................................... 26
Appendix II ......................................................................................................................... 30
Appendix III ....................................................................................................................... 32
Appendix IV ....................................................................................................................... 33
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1. Background
1.1. Hearing system’s anatomy and physiology
The human auditory system can be divided into the peripheral auditory system (the outer,
middle and inner ear), the central auditory system (auditory nerve, auditory pathways and
different brain stem nuclei) and the auditory cortex (Møller, 2006; Pickles, 2005; Stach, 1998)
(Figure 1 and 2).
Figure 1. The hearing system. (Permission from MED-EL Medical Electronics 30 /04/14).
7
Figure 2. The central auditory systems and the auditory cortex. Ascending auditory pathways in the
auditory system (adapted from Kiernan, 1987, permission from Wolters Kluwer Health/Lippincott
Williams & Wilkins Book Permissions Group 28/4/14).
The sound wave reaches the ear, and vibrates the tympanic membrane. The vibration is
amplified by the special construction of the ossicles in the middle ear. The stapes transfer the
mechanical vibration into the fluid filled inner ear through the oval window creating a
travelling wave along the basilar membrane in the cochlea (Frolenkov, Belyantseva, Friedman
& Griffith, 2004). The sensory cells of hearing, the inner and outer hair cells, are parts of the
organ of Corti, which is placed on the basilar membrane in the Scala Media along the spiral of
the cochlea (Figure 3). The travelling wave stimulates the hair cells and mechanically
are bent in sharing motion. The influx of ions depolarizes the inner hair cell, creating a release
of transmitter substance. This release creates an electrical signal in the auditory nerve at the
synapse connection with the inner hair cell. The role of the outer hair cells is mainly to
amplify soft sounds. The nerve signal is transferred through the auditory pathways to the
cortex. During the transfer several modalities of the sound such as frequency, loudness,
temporal information and direction are relayed. In the auditory cortex the different aspects of
the sound is compiled into meaningful information and compared to our memory of earlier
detected sounds (Møller, 2006; Ohlemiller, 2008; Pickles, 2005).
8
Figure 3. Cross section of the cochlea (A) and the structure of the organ of Corti (B) (adapted from
Emanuel & Letowski, 2009, Chapter 8, page 292, Figure 8-13). (Permission from Wolters Kluwer
Health 05/13/13).
1.2. Hearing loss
There are two types of hearing impairment according to which part of the ear is affected,
conductive and sensorineural hearing loss. Conductive hearing loss is caused by difficulties in
the transmission of sound in the outer or middle ear. Sensorineural hearing loss is caused by
damage in the inner ear, auditory nerve or the central auditory system. Sensorineural hearing
loss can be divided into cochlear, retrocochlear (auditory nerve) and central (auditory system)
hearing loss. Combined type of hearing loss is caused by both conductive and sensorineural
damages (Møller, 2000; Stach, 1998).
A hearing loss or deafness can be hereditary (genetic cause or disease) or acquired (infectious
diseases, head trauma, exposure to noise, ototoxic drugs or chemicals, or age). A common
example of a conductive hearing loss is a chronic middle ear infection and a typical
sensorineural hearing loss can be caused by aging, ototoxic substances or noise exposure
(Clark, 2008; Møller, 2000; Rybak, 2008). Hereditary hearing loss is sensorineural and often
bilateral. Approximately 70 % of the hereditary hearing loss is nonsyndromic, while 30 % is
syndromic SNHL (Sivakumaran et at, 2013). Pfister and Rehm (2003) reported that
nonsyndromic hearing impairment is a hereditary hearing loss without any other medical
problems, while syndromic hearing impairment is associated with other medical problems.
Wonkam et al (2013) examined 582 patients in Cameroon and identified 15 % genetic causes,
of which 86 % were nonsyndromic and 14 % syndromic.
Prenatal infections caused by human cytomegalovirus (CMV), such as herpes or rubella,
affects up to 5 % of children born in developing countries (Manicklal, Emery, Lazzarotto,
9
Boppana, & Gupta, 2013) and 0,2 % to 1,2 % of children born in developing countries
(Karltorp et al, 2012). CMV may cause congenital developmental delay, heart defects, eye
abnormalities and auditory defects such as sensorineural deafness (Freeland, Jones &
Mohammed, 2010). Sousa, França Barros and Sousa Neto (2012) found congenital rubella in
16 % of 43 children with severe bilateral sensorineural hearing impairment in a cross-
sectional study in Brazil.
Untreated human immunodeficiency virus (HIV) leads to acquired immunodeficiency
syndrome (AIDS). According to UNAIDS (2012) 34 million people were infected with HIV
in 2011. Van der Westhuizen, Swanepoel, Heinze and Hofmeyr (2013) found a significant
increase of sensorineural hearing loss with HIV/AIDS progression.
Acute otitis media (AOM) is a common infection in children worldwide. In a study conducted
by Alabi, Abdulkarim, Fatai and Abdulmajeed (2009) in a Nigerian hospital 64 of 200 (16 %)
children had AOM as a result from fever episodes, and 40 % from malaria. AOM can be lead
to a chronic otitis media (COM) that needs antibiotic treatment (Faddis, 2008). Untreated
COM may cause damage of tissue and bone erosion and lead to conductive hearing loss
(ibid.).
According to Nelson, Nelson, Concha-Barrientos and Fingerhut (2005), the noise-induced
hearing loss (NIHL) from occupational noise is a global problem and estimated to constitute
16 % of the hearing problems in the world. NIHL affects the higher frequencies as 3000, 4000
and 6000 Hz showing characteristic 4000 Hz notch in the audiogram (ibid.), see section 1.5
Audiometry. According to the WHO (1991) the degree of hearing loss can be defined using
the average of hearing level from four frequencies (500, 1000, 2000 and 4000 Hz) (Table 1.).
Table 1. Grades of hearing impairment. Audiometric ISO value = The average of hearing level at
500, 1000, 2000 and 4000 Hz.
Grade of impairment
Corresponding
audiometric ISO value
Performance
Recommendations
0 - No impairment
25 dB or better
(better ear)
No or very slight hearing
problems. Able to hear
whispers.
1 - Slight impairment
26-40 dB
(better ear)
Able to hear and repeat words
spoken in normal voice at 1
meter.
Counselling. Hearing aids may be needed.
2 - Moderate
impairment
41-60 dB
(better ear)
Able to hear and repeat words
spoken in raised voice at 1
meter.
Hearing aids usually recommended.
3 - Severe impairment
61-80 dB
(better ear)
Able to hear some words
when shouted into better ear.
Hearing aids needed. If no hearing aids available, lip-
reading and signing should be taught.
4 - Profound
impairment including
deafness
81 dB or greater
(better ear)
Unable to hear and
understand even a shouted
voice.
Hearing aids may help understanding words.
Additional rehabilitation needed. Lip-reading and
sometimes signing essential.
Ototoxicity is defined as hearing loss caused by drugs or chemicals through damaging the
inner ear, both the hair cells by cellular damage, and also the vestibulo-cochlear nerve
(Johnson & Morata, 2010; Rybak, 2008). The inner hair cells (IHC) can be damaged after the
use of large doses of quinine (Ruedi, Furrer, Lüthy, Nager & Tschirren, 1952), which used to
treat severe malaria in 58 countries (33 in Africa) as the first line of treatment (WHO, 2013,
table 6.2). Gürkov et al (2008) found significant cochlear hearing loss with quinine treatment
comparing to that of artemether/lumefantrine or otovaquone/proguanil treatment in a
randomized clinical study in Ethiopia. Later drugs are used as a second treatment alternative.
10
Aminoglycosides, antibiotics such as neomycin and gentamycin, and cisplatin used for
treatment of cancer can cause sensorineural hearing impairment by producing oxidative stress
and damaging first row of OHC (Schacht, Talaska & Rybak, 2012). A retrospective study of
Freeland et al (2010) conducted in Tanzania investigated 200 Tanzanian deaf children in the
ages 5-12, of which 72 had had fever and 67 had been treated by ototoxic drugs such as
quinine and/or gentamicin. According to Zhao and Mackenzie (2011) the ototoxicity from
antimalarial drugs is well known, but the effects of the parasite Plasmodium falciparums on
hearing loss needs more investigation. See further 1.3.1.
1.3. Hearing loss in a global perspective
Hearing loss can cause social and economic difficulties for individuals, families and
countries. In 2005 it was estimated that 278 million people in the world had a moderate to
profound (defined in table 1) hearing impairment (WHO, 2006). In 2012 it was estimated that
360 million persons had disabling (greater than 40 dB) hearing loss (WHO, 2012b). Nelson et
al (2005) found occupational noise as a health problem worldwide, especially with the lack of
hearing loss prevention programs in working environment in developing countries.
Untreated ear infections are common causes of hearing loss in low income countries (WHO,
2006). Diagnosed cases are often treated with cheap and effective antibiotics such as
aminoglycoside leading to ototoxic effects causing permanent hearing impairment in patients
of all ages (Lee et al, 2005).
Infectious diseases such as meningitis, measles and mumps can lead to hearing impairment.
There is a meningitis-belt across sub-Saharan Africa including Kenya covering over 400
million inhabitants (WHO, 2012a). Bacterial meningitis is a serious public health problem in
this belt-area (Agier et al, 2013). The main environmental causes for childhood deafness in
Cameroon, sub-Saharan Africa, are reported to be meningitis (34 %) and rubella infection (0.5
%) (Wonkam et al, 2013).
1.3.1 Malaria
Malaria is transmitted to human by Plasmodium parasites through infected mosquitoes.
Malaria is a common disease in sub-Saharan Africa, but also Asia, Latin America, and the
Middle East and parts of Europe. In 2012 there were 207 million cases of malaria and about
627 000 deaths from malaria were reported worldwide (WHO, 2013). Africa accounted for
165 million cases and about 562 000 deaths.
Malaria diagnosis and treatment is very important but there are well-known side effects from
the drugs used for treatment. Quinine, one of the most common antimalarial treatments, can
cause ototoxic symptoms such as hearing loss and tinnitus (Shine & Coates, 2005). According
to Lee et al (2005) also other antimalarial such as chloroquine and mefloquin are ototoxic.
The national guidelines in Kenya recommend artemether-lumefantrine for elementary malaria
and quinine for severe malaria and sulphadoxine-pyrimethamine in pregnancy (Ngure,
Nyaoke & Minja, 2012) on the basis of efficacy (against resistance) and reasonable price.
1.4. Tinnitus
Tinnitus is the perception of sounds (e.g. ringing or buzzing) in the absence of any external
auditory stimulation and chronic tinnitus is often related with hearing loss caused by aging or
noise exposure (Eggermont & Roberts, 2004). Prevalence studies in high-income countries
11
indicate that tinnitus is a common phenomenon affecting an average of 10-15 % of the adult
population (Andersson, Baguley, McKenna & McFerran, 2005; Pinto, Sanchez & Tomita,
2010). The prevalence of tinnitus in low income countries has hardly been studied. Sogebi
(2012) found the prevalence of tinnitus in Nigerian middle aged and elderly patients to be
14.5 %.
According to Eggermont and Roberts (2004) chronic tinnitus is often connected to hearing
impairment, caused by NIHL, or aging or ototoxic drugs. There are drugs such as antibiotics,
anti-inflammatories (aspirin, ibuprofen), antimalarials (quinine, mefloquin) and cytotoxics
(cisplatin, carboplatin) that may cause tinnitus as a side effect (Lee, Mistry, Uppal &
Coatesworth, 2005). There are also other causes of tinnitus such as various diseases (e.g.
Meniere's disease, vestibular schwannoma), cardiovascular diseases, neck and head injuries,
infections (e.g. meningitis), dental problems, psychological factors (stress, depression). Even
individuals with normal hearing can have tinnitus (Lockwood, Salvi and Burkard, 2002).
Tinnitus severity has not been found to be related to hearing loss, age or gender (Pinto et al
2010).
1.5. Audiometry
Psychoacoustic measurements are used to determine hearing thresholds. One of the methods
used is pure tone audiometry (PTA), which represents the weakest sound a person can hear at
certain frequency. This is a detection test in which the listener must actively respond to the
sound signal by pressing a button when the listener hears a beep. PTA is measured according
to standardized measurement of the so-called ascending (upward) or modified Hughson-
Westlake method (Almqvist et al, 2004; ASHA, 2005). The tones are presented either as air
conducted signals through a standardized headphone in the ear, or bone conduction signals
through a bone conducted phone located on the processus mastoid behind the ear. When the
hearing threshold is recorded for a specific test frequency, it will be marked in an audiogram.
In an audiogram the level of 0 dB hearing level (dB HL) at all test frequencies, is the average
value for young normal hearing males (18-30 years of age). The PTA hearing test examines
the hearing thresholds (in this order according to the Hughson-Westlake method) at 1000,
2000, 3000, 4000, 6000, 8000, 1000, 500, 250 and 125 Hz. The measurement is conducted in
one ear at a time. The first signal is presented at a well audible level and then reduced in 20
dB steps until the tone is not perceived. Then the level is increased in 5 dB steps until the tone
becomes audible again. The level where you first get three repeated responses is the level
specified as the hearing threshold.
WHO (2010) has a recommendation for hearing screening of newborns for early detection of
hearing impairment and Olusanya (2011) insists the development of this program worldwide.
The methods used in newborn hearing screening are different automated tests such as
otoacoustic emissions (AOAE) testing and automated auditory brainstem response (AABR).
This screening test give a pass or fail result and further diagnostics are needed to establish and
confirm hearing loss or deafness (Neumann & Indermark, 2012). School screening is used for
early identification of hearing impairment in school children often based on screening
guidelines from the American-Speech-Language-Hearing Association (ASHA, 1990).
Screening procedure checks frequencies 1000, 2000 and 4000 Hz and are tested at a screening
level 20 dB HL, each ear separately at the same way as a normal hearing test. A screening
level of 20 dB HL means that only hearing thresholds higher than 20 dB HL are recorded.
12
1.6. Tele-audiology. The Kuduwave audiometer
In Africa, only South Africa and Egypt have educated audiologists to diagnose and treat
hearing loss. This means that in the major parts of Africa there are very few professionals that
can diagnose and treat persons with hearing impairments (Fagan & Jacobs, 2009). In Kenya
as a whole there are only 14 audiologists and most of them work in private clinics. One way
to solve this problem is to enable the few existing professionals to use new, internet-based
methods, like tele-audiology, including video otoscopy, hearing aid fitting and hearing tests
by computer links.
The future of tele-audiology offers opportunities to reach out to the distance places with
hearing health care (Swanepoel, Olusanya & Mars, 2010). Swanepoel (2012) emphasizes the
importance of hearing health care and suggest tele-audiology, as well as other health care
systems using tele methods, as the future for providing hearing health services worldwide.
Audiology telemedicine, for example interactive video, teleconsultation, testing patients at
distant sites, is developing according to Krumm and Syms (2011) and includes many
diagnostic tools such as video otoscopy, tympanometry, hearing aid fittings, TEOAE,
distortion product otoacoustic emissions (DPOAE), AABR, videonystagmography (VNG) as
well as hearing testing and counseling.
Tele-audiology diagnostic is a new method that enables hearing to be assessed at a distance
with a portable tele-audiology device. An example is a robust and suitable equipment
including an audiometer (KUDUwave-5000, Figure 4.), appropriate software and soundproof
headphones, uses broadband, webcam and Skype connection, for distance hearing tests. The
test can be performed both automatically and manually (Swanepoel et al, 2010). Complete
audiometry can be implemented for both air and bone conducted sound stimulation with plug
phones and bone conductor placed in the fore-head. The audiometer has two microphones on
the circumaural earcup that monitor the environmental noise in octave bands during testing
and this is visually represented in real-time on the software together with the test results. The
monitoring of the environmental noise secure the quality of the measurements especially since
no sound proof booths are used.
Figure 4. KUDUwave audiometer showing insert earphones, circumaural earcups housing
audiometer, and forehead bone conductor mounted centrally on headband. Source: GeoAxon, Pretoria,
South Africa
13
In a pilot study conducted in South Africa using tele-audiology to compare face-to-face and
remote testing (Swanepoel, Koekemoer & Clark, 2010), no clinically significant differences
between the results from these two audiometric tests were found. The use of tele-audiology
has now started in Kenya and this might have great significance for the development of
hearing healthcare in Kenya and other African countries as well as in countries outside Africa.
1.7. Facts about Kenya, development and hearing health care in Kenya
Figure 5. Map of Kenya.
Kenya is a republic with a population of over 43 million in 2012 (World Bank Group, 2014).
Life expectancy was 57 years in 2011 (Sida, 2013). Area of Kenya is 582 646 km² and there
are many different ethnic groups such as kikuyu about 17 %, luhya 13.5 %, kalenjin 13 %, luo
10 %, kamba 10 %, other 37 % (cencus of population 2009) covering 42 tribes and 42
languages. Official languages are Swahili (Kiswahili) and English. The majority religions are
Christianity (82 %), Islam 11 % and others 7 % (Sida, 2013). Mean years of school education
in Kenya is 7 (Sweden 12) and Gross National Income (GNI) is 1.5 per capita (Sweden 36)
(UNDP, 2013).
Various infections such as meningitis are common causes of hearing loss in Kenya. Otitis-
media is one of the ear, nose and throat (ENT) diseases in Kenya that can cause hearing
impairment (Njoroge & Bussmann, 2006). One of the common causes of hearing loss in
Kenya is otological trauma. Oburra (1998) examined ear trauma, hearing loss and tinnitus in
Kenyan patients and found that road traffic accidents and trauma caused by violent law
enforcers were the most common causes of otologic trauma. The most common complaints
were pain, hearing loss and tinnitus.
1.7.1. The hearing clinic in Nyeri
In collaboration between Umeå University, Falun Hospital and Kenya Ear Foundation (KEF)
was initiated in 2002 and a hearing clinic was officially inaugurated in Nyeri, Kenya in 2003.
There were four personnel working at this clinic. The clinic offered hearing tests with PTA
and KW. The use of the KW devise was found as a valuable complement and the use was
growing and especially the automated version of the testing were used as a complementary
test which enabled the testing of more patients in a shorter time. However, some problems
14
were noticed when using the KW device. Some patients (especially women with traditional
hair-styles) found the device uncomfortable. In some older patients there were problems with
understanding the more complicated instructions for the test. But on the other hand young
patients had no problems with the KW testing.
At the clinic hearing aid fitting was offered with different kinds of behind-the-ear and body
worn hearing aids, but not in-the-ear hearing aids because this was a low-cost hearing clinic.
They offered both analog and some digital hearing aids. They had learned how to manufacture
molds for hearing aid fitting and had gotten the equipment from Sweden to be able to
manufacture these.
There has been a development of the installment of more health care clinics also offering
hearing health care in Kenya the last 5 years which is an improvement and recognition of the
silent disability of a hearing loss. The personnel at the Nyeri clinic had also noticed a rising
awareness among people of the need to take care of their hearing and seek help in time is also
a result of the increased number of clinics.
The clinic offered AOAE screening for newborn at the delivery ward and hearing screening at
schools around Nyeri. During the years 2005 to 2011 18 259 hearing tests were conducted at
schools in Nyeri. These tests revealed that 2.4 % (n=428) of the school children had a possible
hearing loss above 20 dB HL. These children were recommended for further testing and
diagnosis to their family physicians or hospital.
Problems with acceptance of hearing loss especially in children were raised by the personnel
who also offered counseling for families to help both them and the children. Now 64 schools
for the deaf are available in Kenya.
Problem formulation
The problem to provide the audiological diagnosis, intervention of hearing impairment and to
develop the hearing health care services is important to investigate in developing countries
such as Kenya. New technologies like tele-audiology will help quicken the development and
make audiological diagnoses more available in remote parts of the country, but the devices
and services needs to be evaluated. There is a need for validation of new methods under field
conditions to make the diagnoses of more patients secure.
The knowledge of causes and status of the hearing health in the patients visiting the clinics
may also differ from patients in developed countries and this need to be investigated.
1.8. The aims and research questions
The overall aims of this field study were to describe the patients visiting a hearing clinic by
investigate the hearing and the possible causes for hearing loss in these patients. Another aim
was to evaluate a new method for tele-health within audiology in Kenya by validation the
diagnostic method used and to pilot test the distance use of the method.
1.8.1. Specific research questions
1. What characterizes the hearing and what are the possible causes of hearing loss in
patients visiting a hearing clinic?
15
2. Do diagnostic results from automated testing with the Kuduwave audiometer, under
field conditions, differ from results from traditional pure tone audiometry, performed
in sound proof boxes?
3. Can the Kuduwave method be used on distance using tele-audiology?
2. Materials and methods
2.1. Design and approach
During a four week period, a field study was conducted in a Kenyan central province.
The study used a quantitative research approach, in which the goal is to measure and explain
(Nyberg, 2000). The design was to investigate a consecutive sampling of patients visiting a
hearing clinic during a set period of time. To identify the amount of visitors, the prevalence of
hearing loss, tinnitus, ear diseases and malaria a questionnaire was used and hearing tests
were performed. The questionnaire was used to ascertain the underlying known causes of
hearing loss, which may vary in different countries.
A study-specific, self-reported questionnaire was used to characterize the patients and to
investigate the possible causes of hearing loss (Appendix I). The questionnaire was assembled
by using part of the questions from a validated questionnaire: Questionnaire on Hearing and
Noise NoiseScan, which was constructed as an analysis program (Pyykkö, Toppila, Starck,
Juhola & Auramo, 2000).
The quantitative measurements of the hearing ability of the patients were performed using, in
some cases, two different methods, which were compared.
A tele-audiology method was tested in a pilot study by doing a hearing test at a distance
between two clinics.
2.2. Samples
All patients, adults and children, who sought treatment in the hearing clinic at Mathari
Consolata Mission Hospital in Nyeri during 31st July to 30th August 2011were included in the
study. All patients who came to clinic were asked to participate. Patients, who did not
understand English, were helped with translation by one of the staff at the clinic. Participation
was voluntary. Of the eligible 82 patients 80 were included in the study and two patients
declined participation.
Eleven patients were included in the validation of a new tele-audiology method with
Kuduwave.
The hearing clinic consisted of four personnel. All four employees were included in the study
and participated by answering a questionnaire.
16
2.3. Data collection
The study-specific questionnaire used, contained socio-demographic information (gender,
age), reasons for seeking care, history of ear diseases, ear surgeries, tinnitus, exposure to noise
and solvents and questions about malaria and medication.
Traditional hearing test with pure tone audiometry (PTA) was performed on all patients if
possible. PTA was performed in a sound-isolated booth using a clinical audiometer (Madsen
OB 822).
The telecommunications audiology method (Kuduwave, KW) was validated. Kuduwave 5000
(GeoAxon, South Africa), a portable audiometer and was used with insert earphones.
Measurements were performed in a silent office room. Measurements with tele-audiology
were performed on a number of patients and then compared with traditional hearing
measurement methods as pure tone audiometry (PTA) in the same patients. The validation
was done by comparing the differences in the audiograms made by the two methods in a
sample of patients (n=11). These patients were selected during the first week of the study.
To evaluate the tele-audiology function, a pilot hearing measurement was done at a distance
between two clinics.
The questionnaire aimed for staff members (Appendix II) contained background information
as gender, age, education, degree, working length, and duty and the results were used for
background information.
2.4. Data analysis
All statistical analyses were performed using IBM® SPSS® version 22. The data from
questionnaire regarding experience of hearing loss, tinnitus, malaria, exposure to noise are
presented descriptively with frequencies, means, medians and percentages. Paired Students t-
tests were performed to compare the left and the right ear in patients.
The validation of the tele-audiology method in comparison to PTA, was conducted, using
results for each person at each frequency between 125-8000 Hz. The Bonferroni correction
was used as a post hoc adjustment of p-values on this t-test to control false-positive results.
-value (0.05) was divided with 18, which is the number of tests (two ears and 9
frequencies=18) giving the new significance level (0.0027). Both results from original t-tests
and post-hoc adjustments will be presented.
3. Ethical considerations
This study has been evaluated by Kenya Ear Foundation in Nairobi by Executive Director of
-Sotik, Kenya.
Helgesson (2006) emphasizes the importance of informed consent, where preserving the
autonomy, privacy, and that the subjects are not exposed to unacceptable risks. Participants
were informed of the confidentiality and voluntariness of their participation and the right to
withdraw any time without any influence on their future treatment. All of the processing and
archiving of material takes place in confidentiality (WMA Declaration of Helsinki, 2008).
Participants (patients and staff) were informed verbally and by signing the consent form
17
(Appendix III and IV). The potential risks to the subject to be injured during a hearing test are
minimal. It is more time consuming to do double audiometric testing, which was done in the
validation section with 11 patients, but none of the patients expressed any concern of
difficulties.
4. Results
Full results are reported in the article manuscript (Appendix I) and are only summarized here.
Eighty patients and four employees were included in the study. The personnel had been
working 4-9 years at this clinic, their median age was 37.5 years (range 32-46). Three of them
worked as a patient attendants and one of them as a manager and acoustician. Characteristics
of patients are presented in Figure 1 and Table 1, 2 and 3. Thirty-five adult patients and one
child complained of tinnitus; 40 patients (about 50%) had a history of malaria and received
malaria medication; 37 patients had hearing aids. Median hearing thresholds are demonstrated
in Figure 2-4. Figure 2 shows the median hearing thresholds for 11 children and 29 adults
with malaria. Children had more hearing loss in the low frequency range compared to adults.
Paired t-g
thresholds, see Figure 3. Comparative results between PTA and KW, calculated with
dependent -
separately for right and left ear, showed significant differences on frequencies 250-2000 Hz
on the right ear and 250 Hz and 1000 Hz the left ear, while the differences on the left ear did
not reach significance after Bonferroni correction, see box plot in figure 5 and 6. In all cases
the KW method resulted in higher thresholds compared to PTA.
5. Discussion
This study shows that among adult patients seeking care, tinnitus seemed to be a common
symptom. Thirty-five out of 54 patients presented at Nyeri clinic had tinnitus. About 50 % of
all patients had a history of malaria. A comparison between two methods of hearing testing,
PTA and KW in 11 patients resulted in significant differences between the methods on
frequencies 250-2000 Hz on the right ear and 250 and 1000 Hz on the left ear.
Low-income countries such as Kenya, often have lack of resources in audiology. There are
few specialists e.g. ENT-doctors, audiologists and speech therapists. There is often also lack
of equipment such as measuring devices, ear mold manufacturing and hearing aids
(McPherson, 2014). This lack of expertise is a big problem and cause major complications for
patients with impaired hearing, from newborn to the elderly for diagnoses and hearing
rehabilitation. National and international aid projects try to solve the problem and the
establishment of the hearing clinic in Nyeri 2003, was a collaboration project between hearing
clinics in Sweden and the Kenya Ear Foundation. This field study had the aim to characterize
patients seeking care in this clinic and it also wanted to investigate the possibilities and
validity of a new tele-audiology method that could be a future development for such clinics in
developing countries (Swanepoel, Olusanya & Mars, 2010).
This field study used a quantitative approach by using questionnaires, hearing tests and a
comparison between PTA and KW under field conditions.
As a special part a pilot test was performed to evaluate the use of tele-audiology in practice by
doing a hearing test at a distance. The advantage of doing distance testing is that skilled
personnel situated in one clinic can be used to test more patients in several locations also the
patients do not need to travel long distances to visit the clinic (Swanepoel, Koekemoer &
18
Clark, 2010). Potential difficulties with such a test could be the Internet connection required
for implementation. In this study the connection worked successfully. Some of the challenges
in tele-audiology are test environments, equipment with both hardware and software and
Internet connection (Swanepoel, Olusanya & Mars, 2010). Lancaster, Krumm, Ribera and
Klich (2008) emphasize the importance of adequate bandwidth speed for Internet and the
interactive video needed a webcam to provide tele-audiology services. Our conclusion from
the pilot testing was that tele-audology in hearing health care has a potential by providing
services to distant locations.
The testing of 11 patients by comparing these two diagnostic methods was a small validation
of the new tele-audiology method. The comparison of PTA and KW was made using a
-test to compare the individual values of the measured variable (dB HL)
for each frequency (125-8000 Hz) to examine if there was a significant difference between the
methods. Since many comparisons were made (9 frequencies on 2 ears) a Bonferroni
correction was performed as a post hoc test to avoid a type I error (Armstrong, 2014). This is
a correct statistical method for multiple comparisons for partly dependent variables. However,
in this case the use of a stricter significance level (p< 0.0027 versus p< 0.05) might make the
results of the comparison better and thus underestimate the found differences. The differences
found between the two methods showed higher thresholds with KW on the lower frequencies
in both ears. Swanepoel, Koekemoer and Clark (2010) used the same analysis method in their
study including 30 normal hearing persons in clinical sound treated rooms and in 4% of cases
the results differed by 10 dB. MacIennan-Smith, Swanepoel and Hall (2013) had a bigger
sample (n=147) in validation of PTA and KW and they also analyzed their results using
-test and in 5% of cases the results differed by more than 5 dB. None of the studies
did find any significant differences between KW and PTA. Storey, Muñoz, Nelson, Larsen
and White (2014) found significant different results for the noise conditions (non-sound-
treated room) between KW and PTA and they also found 5% of cases the results differed on
thresholds with KW compared to PTA as much as 60 dB at 250 Hz and 8000 Hz, with higher
thresholds from KW.
Traditional pure tone audiometry was performed in a sound-isolated booth whereas the KW
measurements were done in an office room. The rooms were not well isolated, and one could
affected the results in the low frequency range. Thresholds on low frequencies are usually
more affected by higher background noise (Bromwich, Parsa, Lanthier, Yoo and Parnes,
2008). However, the aim of the validation was to test the KW under fields conditions and
sound proof boxes are seldom available in distant clinical. MacIennan-Smith et al (2013) used
continual monitoring of noise when testing the KW audiometer without audiometric booth in
comparison with audiometric booth. Another reason for the differences between the methods
may have been the location of the insert earphones near the eardrum with KW, which can be
difficult to manage in a clinical situation.
The response rate of this study was high. All 80 patients filled the questionnaire, and parents
filled instead of their children. Newton, Macharia, Mugwe, Ototo and Kan (2001) studied the
use of questionnaire and PTA in ENT clinics in six districts in Kenya and they found a
response rate of 88% of parents for children aged 2-7.5 years and they concluded that the use
of questionnaire is useful in developing countries to detect hearing loss.
Approximately 32 million children (9%) have a moderate to profound hearing loss worldwide
(WHO, 2012B). Early detection of hearing loss in children is important and in this study there
were 26 children. This hearing clinic had done 18 259 hearing screening tests at schools in
19
Nyeri during the last six years and they found that the overall % of children with hearing loss
was 2.4. This may be an explanation for the large number of children in this study because
those children who failed the hearing screening were recommended for further testing.
Omondi, Ogol, Otieno and Macharia (2006) found hearing impairment in 2.5% of school
children in Kisumu district, Kenya. It is the availability of audiological health care that is the
problem in most developing countries because there are an insignificant number of
otolaryngologists (Njoroge & Bussmann, 2006). Same problem applies to ENT surgeons and
audiologists, and Fagan and Jacobs (2009) found a number of 40 ENT surgeons, four
audiologists and three speech therapists in Kenya. Parental consciousness of hearing
impairment was investigated by Omondi et al (2006) and the authors found that most of the
parents (67%) were aware of this.
The small sample, 80 patients, should be discussed. More patients over a longer period of
time would have been given more information and dissemination of the causes of hearing loss
than this study did. The selection will be a bias in this study when the patients visiting the
clinic usually know they have hearing problems and this means that the proportion of tinnitus
and hearing loss is much larger than in general prevalence studies. This affected the results in
this study e.g. by showing a tinnitus prevalence (45%) which is higher than in other studies.
One of the quantitative research criteria applicable to a study is generalizability (Polit & Beck,
2010). One may question whether the selection bias in this study is an obstacle for the
generalizability of our study since participants actually sought hearing health care due to high
probability of having hearing problems. The prevalence of hearing problems thus cannot be
generalized to the population, but only to the population that actually seek care. The survey
questions may give some information about possible causes of hearing loss.
According to Patel and Davidson (2003) it is important to know what we intend to measure in
a quantitative study, where both validity and reliability have an important role. Validity means
the extent to which a concept, conclusion or measurement is well-founded and corresponds
accurately to the real world and the researcher is attempting to measure, and reliability implies
accuracy in measurements (Holme & Krohn Solvang, 1997). Using standard questionnaires
with relevant questions for patients, the study has endeavored validity. The number of patients
in comparisons between PTA and KW was small, and this affects validity. Audiometric
testing was performed in a reliable manner according to standard clinical national standard
method, and in this way has reliab
correct decisions about the reliability of the measurement methods, and this confirm the
validity and reliability.
One difficulty with a field study is the unpredictable and unexpected events that may
influence the planned procedures e.g. weather conditions, power failure, and lack of hearing
aids. Heavy rain resulted in indoor water damage and prevented us from patient examination
in two days. Another obstacle was a power failure which prevented us from performing
hearing tests on 10 patients who were present at the clinic. Another day we had no electricity
and no patients. Hearing aids are an important part of rehabilitation and this kind of clinic
depends on assistance and economic support in order to provide aids for patients. The strength
of this study was the interest among the population for participation, only few declined
participation. All patients were motivated to participate in the study.
The characteristic of Nyeri clinic was patients
They had many patients from the whole Kenya but even from neighboring countries such as
Rwanda and Sudan.
20
The author had also done interviews with the staff, but the qualitative approach was not
included in this study. The decision to use one approach was made to make the study report
manageable. Recommended further research can use alternative approaches, e.g. qualitative,
for studying the hearing health care development in a region in Kenya. A more extensive
quantitative study can be achieved by extending the time period for data collection from one
to several months to reach more participants in the study. Another option might be to use both
quantitative and qualitative approach rather than use only one in a study.
21
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26
Manuscript
(According to the assignment for the review. Focus in results.)
Appendix
I. Questionnaire to patients
II. Questionnaire to staff
III. Information about this study and consent form to patients
IV. Information about this study and consent form to staff
Appendix I
Institution for Clinical Sciences, and Institution for Neurobiology
Intervention and Technology Health Sciences and Society
Section for Audiology Section for Nursing Care
Karolinska Institution Karolinska Institution
SE-141 83 Huddinge SE-141 83 Huddinge
Sweden Sweden
Questionnaire
Because all replies are anonymous, it will help us to understand your answers
better if we have a little background data from you, as covered in the following
questions.
Are you: Male Female
What is your age?
Which of the following describes best
your main activity?
employment or self employment
27
retired
housework
student
seeking work, unemployed
other (please specify)
Do you have any hearing problems? Yes No
Do you have somebody in your family who has hearing problems?
Yes No
If yes, who, and how is he/she related to you?
Do you have tinnitus (buzzing, ringing or whistling sounds in your
ears)?
Yes No
If you have tinnitus – how long time did you have it?
If you have tinnitus, how often does it occur?
Sometimes
Often
All the time
Have you had any ear diseases?
Yes Acute ear inflammation in childhood
(>3 times) with pain, discharge from the ear
28
Yes Acute ear inflammation as an adult
(>3 times) with pain, discharge from the ear
Yes Chronic ear inflammation with tympanic membrane perforation and
a feeling of deafened ear, discharge from the ear
(lasting >3 months)
No
Do not know
Have you had any operations done in the ear?
Yes No Do not know
If you have had an ear operation, do you know what was done?
Have you been exposed to noise from shooting or hunting?
Yes No
At my present job, I am being exposed to noise as follows:
Noise means surrounding sound that are so loud that you cannot
communicate at a normal voice level.
Yes No
If Yes; Fill in below as carefully as you can.
Noise exposure
29
Noise exposure
Do you use some kind of hearing protectors at work?
Use of hearing protectors:
Always
Often
Seldom
Never
At my present job, I am being exposed to solvents, paints or glues
Yes No
If yes, do you know what kind of substances?
Have you been in an accident?
Yes No
If you have been in an accident, what kind of accident was it? Did you
hurt yourself in the head?
……………………………………………………………………………
Have you had malaria?
30
Yes No
If you have had malaria, did you get some medication?
Yes No
Which kind of medication did you get?
Do you use some kind of hearing aid?
Yes No
Appendix II
Institution for Clinical Sciences, and Institution for Neurobiology
Intervention and Technology Health Sciences and Society
Section for Audiology Section for Nursing Care
Karolinska Institution Karolinska Institution
SE-141 83 Huddinge SE-141 83 Huddinge
Sweden Sweden
Questionnaire (to staff members)
31
Because all replies are anonymous, it will help us to understand your answers
better if we have a little background data from you, as covered in the following
questions.
1. Are you: Male Female
2. What is your age?
____________
3. Did your education continue after Yes No
leaving school?
4. Do you have a Degree or Yes No
professional
qualification?
5. If you have a Degree, what kind of Degree do you have?
________________________________________________________________
6. For how long time have you worked here?
7. What kind of job do you have?
___________________________________________________________
___________________________________________________________
8. How many patients do you see in one day?
______________________________________________________
32
Appendix III
Institution for Clinical Sciences, and Institution for Neurobiology
Intervention and Technology Health Sciences and Society
Section for Audiology Section for Nursing Care
Karolinska Institution Karolinska Institution
SE-141 83 Huddinge SE-141 83 Huddinge
Sweden Sweden
Information about this study and patient consent form
A study will be performed to examine the prevalence of hearing loss, tinnitus, noise exposure,
exposure to chemical substances such as solvents, ear infection, malaria and medication. The
study is going to take place here at the KEF Swedish Hearing Aid Center in Nyeri and
Kaplong, Kenya during the period of August-September in 2011.
We are grateful if you would like to participate in this study. It is voluntary to participate and
you can always cancel your participation.
As a participant we will ask you to answer a questionnaire. We will also do hearing tests.
The questionnaire and the participation will be processed in confidence.
The results of the study will be presented in an essay in which you are treated confidentially.
Thank you for your cooperation.
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..
Consent and signature of participant
33
Appendix IV
Institution for Clinical Sciences, and Institution for Neurobiology
Intervention and Technology Health Sciences and Society
Section for Audiology Section for Nursing Care
Karolinska Institution Karolinska Institution
SE-141 83 Huddinge SE-141 83 Huddinge
Sweden Sweden
Information about this study and consent form
A study will be performed to examine how the tele-audiology does work in Kenya. The study
is going to take place here at the KEF Swedish Hearing Aid Centers in Nyeri and Kaplong,
Kenya during the period of August-September in 2011.
As a participant we would like you to answer a questionnaire and in connection with the
submission to participate in a short interview. The interview will be recorded and after
transcription the tape will be destroyed.
We are grateful if you would like to participate in this study. It is voluntary to participate and
you can always cancel your participation.
The questionnaire, the interview and the participation will be processed in confidence.
The results of the study will be presented in an essay in which you are treated confidentially.
Thank you for your cooperation.
... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..
Consent and signature of participant
34
Article
Hearing health care in Kenya; a regional field study
Turunen-Taheri, Satu ª, Wettergren, Lena -
Corresponding author: Satu Turunen-Taheri, M.Sc., Department of Audiology and
Neurotology, Karolinska University Hospital, Tideliusgatan 12, Rosenlund, SE-118 95
Stockholm, Sweden, Tel +46 703682771, E-mail: satu.turunen-taheri@karolinska.se
ª Department of Audiology and Neurotology, Karolinska University Hospital, Sweden
Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Sweden
Department of Communication Pathology, University of Pretoria, South Africa
Department of Clinical Sciences, Intervention and Technology, Section of Audiology,
Karolinska Institutet, Sweden
35
Abstract
Objectives: To describe hearing health and to evaluate a method for
tele-audiology in a hearing clinic in Nyeri in Kenya.
Study design: Field study with quantitative approach using consecutive sampling of patients
visiting the hearing clinic.
Methods: Questionnaires were answered by patients to identify the amount of visitors, the
prevalence of hearing loss, tinnitus, ear diseases and malaria. In addition, hearing tests of
patients were gathered during a four week. The results of hearing measurements with pure
tone audiometry was compared to that of a new tele-audiology device, Kuduwave, as a
validation testing of the tele method under field conditions. Also the tele-audiology method
was tested in a pilot study by doing a hearing test at a distance.
Results: Eighty patients were included in this study. Thirty-five out of 54 adult patients had
tinnitus. Forty patients received malaria medication and 37 patients had hearing aids.
Comparative results with eleven patients between pure tone audiometry and Kuduwave
showed significant differences on frequencies 250-2000 Hz on the right ear and 250 Hz and
1000 Hz on the left ear.
Conclusions: A field study is an opportunity to get close to the population to be studied.
Tele-audiology offers new opportunities in hearing health care.
Keywords: audiometry, hearing aid, hearing clinic, hearing loss, malaria, noise exposure,
screening, tele-audiology
36
Introduction
Approximately 360 million people worldwide have a moderate to profound hearing loss (>40
dB), of which around 32 million are children (1). Hearing impairment may worsen the
chances to obtain employment.
Tinnitus is the perception of sound in one or both ears in the absence of any external auditory
stimulation. Its prevalence, reported by most epidemiological studies, is around 10-15 % in
average (2, 3). Hearing impairment, aging or ototoxic drugs are some of causes to connected
with chronic tinnitus (4).
Hearing loss and deafness can be congenital (genetic or complications during pregnancy and
childbirth) or acquired (infectious diseases, chronic ear infection, trauma, exposure to noise,
ototoxic drugs/solvents, age). For example a chronic middle ear infection can cause a
conductive hearing loss, while aging, ototoxic substances or noise can cause sensorineural
hearing loss (SNHL) (5, 6). Ear infections such as otitis media, are common bacterial
infections that may result in hearing impairment and affect language development (7).
Noise-induced hearing loss (NIHL) afflicts 16 % of the adult population in the world (8).
Bacterial meningitis is a severe epidemic public health problem in the African meningitis belt
that may result in severe hearing impairment or deafness (9). Over 400 million people lives in
this belt area of sub-Saharan Africa including northern Kenya (10).
Although malaria is a very common disease in Africa, it can also be found in South America,
Eastern Mediterranean, South-East Asia, Western Pacific and East part of Europe.
Worldwide, approximately 207 million cases of malaria and nearly 627 000 deaths due to
37
malaria were reported in 2012. In Africa the estimated number of malaria cases and number
of deaths were 165 million and 562 000 people, respectively (11). One of the main causes for
malaria epidemics is climate, especially after high rainfall (12). Diagnostic testing, malaria
treatment and prevention are important factors in combatting the disease. Unfortunately,
malaria medication such as quinine and chloroquine have ototoxic side effects that damage
the inner ear and cause hearing impairment (13), (14). There is, however, no better
alternative than quinine to treat severe malaria (15).
The Republic of Kenya has a population of 43.18 million people (2012) (16). According to
the World Malaria Report (11) there were 5.8 million reported malaria cases and 785 malaria-
attributed deaths in Kenya in 2012. Recommended medications, according to the national
guidelines in Kenya, are quinine for severe malaria, artemether-lumefantrine for
uncomplicated malaria and sulphadoxine-pyrimethamine during pregnancy (17).
WHO classifies the degree of hearing impairment base on clinical audiometry and by using an
average for the most relevant frequencies for human speech (500, 1000, 2000, 4000 Hz) (18).
Accordingly a moderate hearing loss is equivalent to an average hearing level between 40-60
dB HL. WHO (19) emphasizes the importance of early detection of hearing impairment in
newborn, infants, and in school-age children. Recommended screening methods such as
otoacoustic emissions (OAE) are one of the different approaches to early identification of
hearing impairment. School-age screening guidelines (20) will ensure that children with
hearing impairment will be identified in time and minimized the risk for delays in speech and
language development and poor school education. Thus, hearing screening is cost-effective
for public health and hearing health care.
38
In adults the standard procedure for diagnosing a hearing impairment is pure-tone audiometry
that according to international guidelines (21) determines hearing thresholds at the
frequencies 125-8000 Hz using an ascending method.
Tele-audiology is a new method that enables assessment of hearing at a distance with a
portable tele-audiology device (22). It can improve chances for an early diagnosis of hearing
impairment and enable intervention in a geographically isolated population (23).
The aims of this field study were to describe various aspects of hearing health care in Kenya
by 1) describing characteristics of patients treated at the Nyeri hearing clinic, 2) investigating
the validity of tele-audiology in the measurement of hearing ability, 3) pilot test if the tele-
audiology method can be used on distance.
Methods
The study used a quantitative research approach, in which the goal is to measure and explain
(24). The design was to investigate a consecutive sampling of patients visiting a hearing clinic
during a set period of time.
A study-specific, self-reported questionnaire was used to characterize the patients and to
investigate the possible causes of hearing loss (Appendix I). The questionnaire was assembled
by using part of the questions from a validated questionnaire: Questionnaire on Hearing and
Noise NoiseScan, which was constructed as an analysis program (25).
The quantitative measurements of the hearing ability of the patients were performed using, in
some cases, two different methods, which were compared.
39
A tele-audiology method was tested in a pilot study by doing a hearing test at a distance
between two clinics.
This field study analyzed several outcomes including and results from
questionnaires to identify the amount of visitors, the prevalence of hearing loss, tinnitus, ear
diseases and malaria in the clinic.
The audiologist in this study followed the hearing screening guidelines by ASHA (26) and
every patient were screened with otoscopy before hearing test.
Setting
This field study was performed at the Kenya Ear Foundation (KEF) - Swedish Hearing Aid
Center, Mathari Consolata Mission Hospital in Nyeri, Kenya during four weeks in 2011.
Participants
The study used a consecutive sample approaching all patients who sought hearing health care
at the clinic during 31st July to 30th August 2011 regarding possibly participation. Of the 82
approached patients 80 participated (response rate 98%). All the four employees at the clinic
answered a questionnaire regarding their background.
Measures
Questionnaires
Hearing and Noise NoiseScan (25). The questionnaire contained socio-demographic
information (gender, age), medical history and possible exposures to noise and medications.
40
Hearing measurements
Traditional hearing tests with pure tone audiometry (PTA) were performed in a sound-isolated
booth. For traditional hearing measurements a clinical audiometer (Madsen OB 822) was
used and for tele-audiology a portable audiometer with insert earphones Kuduwave 5000
(KW) from GeoAzon, South Africa was used (27). The KW measurements were made under
field conditions in a quiet office room. The two methods, PTA and KW, were compared
regarding the measured hearing thresholds.
Tele-audiology measurement
In a pilot test one patient in Nyeri was evaluated with KW by a clinician and the author in
Kaplong (317 km away) to investigate how tele-audiology worked in practice by doing a
hearing test at a distance. The results from this hearing test were compared with PTA after
return to Nyeri.
Analyses
Statistical calculations were performed with the IBM® SPSS® version 22. All the variables
from questionnaires were summarized with standard descriptive statistics such as frequencies,
means, medians, percent and standard deviations.
Hearing thresholds were analyzed by calculating and comparing medians for different groups
for each frequency (125-8000 Hz) measured.
Comparison of PTA and the new tele-audiology method with KW was performed using the
audiometric results for each frequency in both measurements between 125-8000 Hz for 11
test. A significant level of *p<0.05 was applied in all analyses. The Bonferroni correction was
used as a post hoc adjustment of p-values on this t-test to control false-positive results. P-
value 0.05 was divided with 18 (number of tests with two ears and 9 frequencies) giving the
41
new significance level of 0.0027. Both results from original t-tests and post hoc adjustments
will be presented.
Results
Participant characteristics
A total of 80 patients, 54 adults and 26 children were included in this study. Two patients
declined to participate. Age distribution is seen in figure 1 and participant characteristics
presented in table 1. Eleven patients were included in the validation of the KW device.
Distribution of adults with tinnitus by sex is presented in Table 2. There were 35 adults with
tinnitus, with a median age of 53 (23-81) years, making a prevalence of 64.8%, of which 35%
had tinnitus continuously. Thirty-three participants with tinnitus had a hearing loss and two
had normal hearing. Table 3 presents the possible etiology to hearing impairment among
patients. Twenty had history of malaria, six had ear inflammation in childhood, five were
exposed to noise from shooting or hunting, three were exposed to noise at work, one patient
was exposed to solvents (and noise) and one was involved in an explosive accident.
A total of 40 patients had had malaria (11 children and 29 adults). All 40 had received
malaria medication. Quinine was given to 17 patients (8 children), four of them got
pyrimethamine, two patients got halofantrine (one child), one sulphamethopyrazine-
pyrimethamine and one chloroquine, 16 received unknown medication (two children). Figure
2 shows the results of median hearing thresholds for all patients that had history of malaria.
All had a hearing impairment. Chil
range compared with adults with malaria.
42
Twelve children out of 26 and 25 adults out of 54 had hearing aids. Four patients started a
hearing aid fitting when they visited the clinic during this study. Seven of the children and 22
of the adults with hearing aid had a history of malaria.
Hearing thresholds
Hearing thresholds for children, women and men are shown in figure 3 and 4. Seventy-five
patients had hearing loss and the remaining five patients who did not have hearing loss due to
this visit, included two patients with tinnitus and three children who controlled their ears after
ear infections. All 75 patients had a hearing loss as expected. In children the hearing tests
showed significantly better hearing in the right ear (Figure 3) at 1000-4000 Hz. The children
had less hearing loss in the high frequencies compared to adults, which was an expected
result. The causes of hearing loss in children were ear infection (n=5), bacterial meningitis
(n=2), mumps (n=1), human immunodeficiency virus (HIV positive) and human
cytomegalovirus (CMV) (n=1) and other unknown syndrome (n=1).
OAE was performed on seven children. None of them passed the test and four of these
children had not been using hearing aid, thus a hearing aid fitting was started during the visit.
The hearing thresholds did not differ significantly between women and men (Figure 4).
Three patients were HIV positive and two of them had severe hearing loss. One patient had a
hearing loss in the low and high frequencies, but normal hearing at middle frequencies, and
this patient had a history of malaria too.
Comparison between traditional hearing test with pure tone audiometry (PTA) and
Kuduwave (KW) – a pilot study
Three patients were pre-tested with KW to enable the best possible performance with the new
method and they were not included in the final comparison.
43
In this study 11 adult patients were included in the comparison of PTA and KW. A twelfth
patient were tested using both methods but had to be excluded, since he was completely deaf
in one ear and had severe hearing impairment in the other ear, which contributed to a negative
outcome when using KW.
tested if the differences in the measured thresholds with respective method
(PTA and KW) differed from zero. A significant difference between the methods was found
(p<0.05) on the frequencies 250 Hz, 500 Hz, 1000 Hz and 2000 Hz on the right ear, and on
the frequencies 250 Hz and 1000 Hz on the left ear. This significant difference remained only
in the right ear (250-2000 Hz) after the Bonferroni correction (p<0.0027), whereas no
significant difference was found in the left ear. In all these frequencies the KW measurements
gave significantly higher thresholds compared to the PTA measurements. The results of
differences for all frequencies are shown, separately for right and left ear, in box plots (Figure
5 and 6).
The evaluation of tele-audiology in practice - a pilot test
Tele-audiology with Kuduwave was performed in Kaplong, Western province of Kenya, and
did the diagnostic application of tele-audiology with KW. The connection was through Skype
with the patient presented at Nyeri hearing clinic (317 km away). The connection worked
successfully. The results were compared to that of the traditional hearing test conducted on
the same patient later at our return to the clinic. The results are included in the comparison
between PTA and KW.
The staff perceptions when using the KW devise in practice was that they found the KW to be
a valuable complement and they used it as a complementary test which enabled the testing of
more patients in a shorter time. However, some problems were noticed when using the KW
device. Some patients (especially women with traditional hair-styles) found the device
44
uncomfortable, some older patients had problems with understanding the more complicated
instructions for the test. But on the other hand, young patients had no problems with the KW
testing.
Discussion
The purpose of the present field study was to examine self-reported reasons for visiting
hearing clinic and to describe the audiological services. We also wanted to validate the tele-
audiology function under field conditions.
The study used quantitative method to describe the characteristic of visiting patients by using
self-reported questionnaires and performing audiometric testing, and validation of KW by
comparing it to PTA measurements. This study used standardized questionnaires and the
audiometric testing was performed using the national standard method, and thus the study has
endeavored both validity and reliability (28). The sample of patients in this study was low
t be generalized to the general population in Kenya, but only to the population
who sought hearing health care during the four week period (29).
Most children, who sought treatment at the clinic, were from the age group 0-9 years. There
were some indications that hearing loss was noticed earlier in boys (62% boys from 1.5-14
years old vs. 38% girls from 3-17) and parents sought help earlier for their sons than
daughters.
KEF Swedish hearing aid center has a hearing screening program for newborn. They use
OAE measurements every day at the Mathari Consolata Mission hospital in Nyeri. Omondi et
al (30) found the average age of first diagnoses of hearing impairment to be 5.5 years in
45
Kisumu, Kenya, where chronic otitis media was the main reason for hearing impairment. In
Sweden universal neonatal screening with OAE are performed in almost all 100 000 babies
born annually since 2005 (31). At the Child
(Socialstyrelsen) (32) recommendation and mapping all newborns are offered a hearing
screening with OAE and hearing screening in connection to school start in Denmark, England,
Finland, Norway and Sweden.
They also have a hearing screening program for school children in Nyeri. The purpose of
school screening project is to identify those who may be at risk of falling into hearing loss
group of handicap among a large population of children. 18 259 screening tests were
performed between 2005 and 2011 resulting in an overall possible hearing loss of 2.4 %.
According to Statistics Sweden (Statistiska Centralbyrån, SCB) there were 888658 pupils in
compulsory comprehensive schools vs. 402 pupils, i.e. 0.05% with impaired hearing in
2011/12 in Sweden (33).
Our results indicate that tinnitus was a common symptom among these patients. The
prevalence of tinnitus was 64.8 % in adult patients with a diverse history of hearing loss,
noise exposure, malaria and malaria medication. Our results are in accordance results from
Eggermont and Roberts (4) which also indicate age, noise induced hearing loss and ototoxic
drugs, such as quinine as a common cause of tinnitus. The large prevalence of tinnitus found
in this study is greater compared to other studies from developing countries (45%) and much
greater compared to the tinnitus prevalence in the general population in developed countries
(14.5%) (3). This could be due to the selection, bias in our study (low number of participants
and specialized clinic). Savastano (34) found that children seldom complain of tinnitus and
Bae et al (35) found otic tinnitus (acoustic source in the ear vs. vascular) as the most common
46
tinnitus in childhood. In this study we identified one adolescent patient with a 4 year history
of tinnitus.
Age-related hearing loss, NIHL, ear diseases and ototoxic medication seemed to be common
causes of hearing loss in this group of patients (see Table 3). About 50 % of patients in this
study had a history of malaria, which is a common disease in sub-Saharan Africa. Gürkov et
al (36) found significant cochlear hearing impairment in patients with history of malaria
treated with quinine.
-frequency range such as
ear infections and medication. However, due to the low number of patients in this study, no
conclusions can be made. There were three patients with known HIV and all of them had
hearing problem. Significant increase in hearing loss during HIV disease progression has been
reported (37).
Age-related hearing loss and NIHL (38), (39) and ear infections (40) are some of the most
common causes for hearing impairment. Freeland et al (41) found that a third of children with
profound hearing loss or deafness in Tanzania had received ototoxic drugs such as quinine
and/or gentamicin against fever without weight control, which can mean an overdosed
medication. Our findings confirm these earlier findings.
As presented in this study less than 50 % of participants (12 children out of 26 and 25 adults
out of 54) had hearing aid. The main reason for the low number of hearing aids is the cost of
these devices. Compared to other clinics, hearing aids was cheaper in this clinic; for children,
a body worn 5000 Kenya shillings (KES), an analog 6000 KES and a digital 14000 KES, and
for adults, a body worn 20000 KES, an analog 25000 KES and a digital hearing aid 45000
47
KES. Children are given priority and those not able to buy one get a free hearing aid, financed
by the Kenya Ear Foundation.
Low-income countries, e.g. Kenya, often have lack of resources in audiology. There are few
specialists such as ENT-doctors, audiologists and speech therapists. There is often also lack of
equipment such as measuring devices, ear mold manufacturing and hearing aids (42). This
lack of expertise is a problem and cause major complications for patients with impaired
hearing, from newborn to the elderly for diagnoses and hearing rehabilitation. National and
international aid projects try to solve the problem and the establishment of the hearing clinic
in Nyeri 2003, was a collaboration project between hearing clinics in Sweden and the Kenya
Ear Foundation.
The staff at the Nyeri clinic could describe a positive development of hearing health care in
Nyeri in recent years. The clinic supported from the Swedish Rotary organization by visits
from voluntary teams including ENT specialists, technical engineer and audiologist. New
hearing clinics have been opened in the last few years in Kenya, however, the clinic in Nyeri
had many patients from different places in Kenya and also from other countries such as
Our findings indicated significant differences in the low frequency range in the comparison
between PTA and KW. The differences between the hearing thresholds measured with PTA
and KW in the frequencies 250-2000 Hz on the right ear, and 250 and 1000 Hz on the left ear
may presumably be caused from disturbing sounds from adjacent rooms. Traditional pure tone
audiometry was performed in a sound-isolated booth whereas the KW measurements were
48
conversation and crying children from the waiting room. This may have affected the results in
the low frequency range (43). MacIennan-Smith et al (44) controlled the environmental noise
by using a monitoring of noise in their study. Their study was conducted in two different
environments with KW; first in a natural environment in a room provided by the retirement
home facility in a quiet furnished room and second in a certified audiometric booth at an
audiology clinic. They found no significant differences. Storey et al (45) found that 5% of the
hearing threshold results with KW compared to PTA differed as much as 60 dB at frequencies
250 Hz and 8000 Hz with higher thresholds from KW and they found a significant difference
for the noise conditions (non-sound-treated room) between KW and PTA. Swanepoel et al
(27) found no clinically significant difference with comparing KW and PTA in the same
sound treated room. Another possible reason for the detected differences may be the
placement of the insert earphones with KW, in an ideal situation the earphones should be
placed very near the eardrum (44) which can be difficult to manage in a clinical field
situation. One patient was excluded from the comparative analysis between PTA and KW,
since the patient was almost deaf in the right ear and had severe hearing loss in left ear. Thus
it was difficult to perform the KW test since despite similar stimulus levels in traditional PTA
and the KW (100-110 dB HL), differences on low frequencies makes it difficult to receive
responses from the worst ear comparing to PTA.
One disadvantage with KW is the fact that some women did not want to take on KW
headphones because they used the wig. KW headphones are larger and heavier than typical
PTA headphones. Pure tone audiometry with one of patients was very difficult to perform
KW better which could be used in such situations.
49
Our limited pilot test of long-distance tele-audiology between Kaplong and Nyeri
demonstrated that the technology works and this development is promising. Similar
comparative study has been conducted (27) between Pretoria, South Africa and Dallas, North
America with no significant differences between PTA and KW measurements and remote
testing through Skype. In order to reach and provide hearing health care to e.g. rural and other
unavailable areas or wherever there is a lack of qualified personnel to perform hearing tests
and hearing screening of infants, tele-audiology can be a good solution (46).
The study identified tele-audiology as a promising future audiological method to be used as
long distance testing in distant and isolated areas. The use of tele-audiology has now started in
Kenya and this might have a great significance also for the development of hearing health
care in other African counties as well as in countries outside Africa. The method can also be
applicable to the northern part of Sweden, where long distance can be an obstacle to the
children and adults hearing health care.
Field studies are of great importance in analyzing the results in a situation-based research.
However, some issues may have great influence on the performance of the study. Power
failure and electricity cut-off, weather (heavy rain, humid and cold indoors) and lack of
material as hearing aids are some issues, that can influence the number of possible
participants and consequently the quantitative results.
Conclusion
Our findings regarding tinnitus prevalence indicates that tinnitus is a common symptom at this
clinic. Hearing loss in connection with a history of malaria was also common. A field study is
an excellent way to do a research study. The sample size of 80 patients is perceived as a
limitation and further research will be needed.
50
Acknowledgements including declarations
Great thanks to my supervisor Associate Professor, Ann-Christin Johnson for all support and
help during this research. Thanks to Associate Professor, Lena Wettergren for all support.
Thanks to De Wet Swanepoel, Ph.D, Associate Professor. Great thanks to Amir Khorram-
Manesh, Associate Professor at Prehospital and Disaster Medicine Center at Sahlgrenska
University Hospital in Gothenburg for support and advises.
Greatest thanks to Joseph Kweya Ayieko, manager of the hearing clinic and Audiologist in
Nyeri, Kenya. Without him this study have not been possibly. Thanks for the helpful staff in
Nyeri hearing clinic and also
Dr Manuel J. D'Cruz, OGW, FRC, DLO, Hon. Executive Director for Kenya Ear Foundation.
Claude Laurent, M.D., Ph.D., Prof in ENT and Lisbeth Olsson, Audiologist
I would also like to thank my husband for all support before, during and after this research.
Finally, great thanks to SIDA, Minor Fields Studies scholarship program and
Audionomföreningen for financial support which made this research possible to perform. The
study was partly financed by Minor Fields Studies (MFS), a Swedish International
Development Cooperation Agency (Sida)-funded scholarship program administered by the
International Agency to University students.
Ethical approval
This study has been evaluated by Kenya Ear Foundation in Nairobi by Executive Director of
in the Consolata Hospital management
in Nyeri.
Conflict of interest
There are no conflicts of interest to declare
51
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54
Figure 1. Age distribution classified in 9 years period for all the patients in this study divided in
female and male participants.
Table 1. Characteristics of the participants
Gender
Participant n=80
Age range
Median age
Women
31 (39%)
21-78
42
Men
23 (29%)
24-83
60.5
Girls
10 (12%)
3-17
9.5
Boys
16 (20%)
1.5-14
5
Employees
4
32-46
37.5
Main activity, adults
Employment
26
Retired
10
Housework
12
Unemployed
3
Other (specify)
2
Missionary
Religious sister
12
4
1
4
0
6 5 5
2
5
5
4
9
4
4 6 5
0
0
2
4
6
8
10
12
14
16
18
0 - 9 10 -
19
20-29 30-39 40-49 50-59 60-69 70-79 80-89
Number
female
male
55
Table 2. Prevalence and characteristics for tinnitus in adults.
Tinnitus (adults)
Adults (female:male)
35 (23:12)
Tinnitus duration
≤1 year
6 (19%)
1≤5 years
19 (61%)
5<10 years
2 (7%)
≥10 years
4 (13%)
Tinnitus, how often?
Sometimes
20 (59%)
Often
2 (6%)
All the time
12 (35%)
Table 3. Characteristics of participants, possible causes for hearing impairment
Children n=26
Adult n=54
Family hearing impairment
history
5
10
Ear diseases in childhood
5
7
Ear diseases as an adult
5
Chronic ear inflammation
0
4
Ear operation
1
5
Exposure to noise
(shooting, hunting)
5
Exposure to noise (work)
3
Exposure to solvents, paint
or glues
1
Accident (head trauma)
3
Malaria
11 (4:7)
29 (16:13)
Malaria medication
11
29
HIV+
1
2
56
Figure 2. The median hearing thresholds for 11 children and for 29 adults, who had had malaria.
Figure 3. The median hearing thresholds for 11 of 26 children who were hearing tested of the
respective frequency left and right ear with traditional pure tone audiometry
0
10
20
30
40
50
60
70
80
90
100
Hearing level (dB HL)
Frequency (Hz)
Left ear,children
Right ear,children
Right ear,adult
Left ear,adult
0
10
20
30
40
50
60
70
80
90
100
110
125 250 500 1000 2000 3000 4000 6000 8000
hearing level (dB HL)
Frequency (Hz)
left ear right ear
57
Figure 4. Women and men, the median hearing thresholds for 48 of 54 adults of the respective
frequency left and right ear with traditional pure tone audiometry
0
10
20
30
40
50
60
70
80
90
100
125 250 500 1000 2000 3000 4000 6000 8000
Hearing level (dB HL)
Frequency (Hz)
left ear,women
right ear, women
left ear, men
right ear, men
58
Figure 5. Box plot of the difference between PTA and KW right ear (R125-R8000). Difference was
calculated by subtracting the individual hearing threshold for each of the 11 patients measured
with PTA from the threshold measured with KW for each frequency between 125-8000 Hz, when
p<0.05 ie 1 * for frequencies 250--test. Same results with the
Bonferroni correction when p<0.0027.
59
Figure 6. Box plot of the difference between PTA and KW left ear L125-L8000). Difference was
calculated by subtracting the individual hearing threshold for each of the 11 patients measured
with PTA from the threshold measured with KW for each frequency between 125-8000 Hz, when
p<0.05 ie -test. The Bonferroni
correction did not reach significance on the left ear when p<0.0027.
