World Journal of Medical Sciences 9 (4): 267-272, 2013
ISSN 1817-3055
© IDOSI Publications, 2013
DOI: 10.5829/idosi.wjms.2013.9.4.81171
Childhood Hearing Loss-A Nigerian Experience and a Call to Action
1O. Olaosun Adedayo, 2Ogundiran Olawale and 3Osisanya Ayodele
1Department of Otorhinolaryngology, LAUTECH Teaching Hospital / 
LAUTECH College of Health Sciences, Osogbo, Osun State, Nigeria
2Department of Otorhinolaryngology, LAUTECH Teaching Hospital, Osogbo, Nigeria
3Department of Special Education University of Ibadan, Ibadan, Nigeria
Abstract: The burden of childhood hearing loss is huge, its effect on affected children devastating and the
economic toll is heavy. Unfortunately much attention is not given to programs that promote early detection,
management and rehabilitation of such children in developing countries. A cross-sectional study of the
prevalence and patterns of hearing loss was undertaken among 127 children aged 5-15 years who presented
for hearing assessment in two ear clinics in south-western Nigeria. Results revealed that majority (72.5%) of the
children were confirmed as having hearing loss and 90.2% of those with hearing loss had disabling hearing loss.
Conductive hearing loss was rampant but sensorineural hearing loss was the most prevalent. Although the flat
audiogram and the flat tympanogram (Type B) predominated, other patterns of tympanograms and audiograms
were also found. In conclusions, in developing countries there should be stronger advocacy by health workers
for programs that will empower them and others who work with children to identify and refer children with
hearing loss promptly. Universal screening of newborns and children should be made mandatory and programs
aimed at preventing conditions and infections that can lead to childhood hearing loss should also be prioritized
and strengthened as a matter of urgency. 
Key words: Childhood Hearing Loss  Disabling Hearing Loss  Early Detection  Rehabilitation
INTRODUCTION currently ranks third on the global causes of years lived
with disability (YLD) index and 15th on the disability
The importance of hearing is grossly underestimated. adjusted life-years (DALY) index (one of four non-fatal
Helen Keller, blind and deaf, emphasized the importance conditions among the 20 leading contributors to the
of hearing by saying "Blindness separates people from global burden of disease) [7, 8]. 
things, but deafness separates people from people"[1]. According   to   the    World Health     Organization,
The origin of   these   words  has  also  been  ascribed  to of the 360 million people (over 5% of the world’s
Immanuel Kant, eighteenth century German population)   affected  by  hearing loss,  about  32  million
Philosopher"[2]. The extreme isolation described by these are children [9]. If milder cases of hearing loss are
words is particularly relevant to children, who need to included,  almost  10%  of  the  world  population  are
interact with people for normal and optimal development. affected by hearing loss making it the most prevalent
Without early intervention children with hearing loss are disabling     condition    globally    [7,   10-12].   It is
condemned to a life of deprived language and cognitive estimated that childhood hearing loss constitutes
development, restricted literacy, poor academic and approximately 25% of this global burden and significant
vocational outcomes, personal-social maladjustments and hearing loss is present in 1  to  6  per  1000  newborns  [7].
emotional difficulties [3, 4]. Childhood onset hearing loss To mitigate the effects and burden of disease in children
also has significant implications for long-term economic many programs have been instituted in many places
costs. It has been suggested that the global burden of worldwide This includes the universal Newborn Hearing
disease for childhood hearing loss may be significantly screening which has been successful in much of the
higher than for adult-onset hearing loss [5, 6] which developed world [13-15].
Corresponding Author: Adedayo O. Olaosun, Department of Otorhinolaryngology LAUTECH Teaching Hospital, 
Osogbo, Nigeria.  Tel: +234-803-3736113. 
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In Nigeria, studies have suggested that the RESULTS
prevalence of hearing loss in school-aged children ranges
between 6.7 and 8.9%, although these studies were A  total  number  of  127  children  (75  from LTH  and
confined to specific age groups or geographical areas 52 from UCH) was studied. The Male: Female ratio was
[16]. It is also estimated that 6000-27,000 babies with 1.2:1. The ages of the children ranged from 5 to 15 years.
permanent congenital and early-onset hearing loss Mean age was 10.2 years (Standard deviation= 2.94years).
(PCEHL)  will  be  born  in  Nigeria  annually  and  about The age distribution was shown in Table 1. Table 2 shows
5000-22,000 of these will live beyond five years of age the diagnostic profile of all the patients studied. There
[17]. Unfortunately, more than 90% of infants in was a wide range of diagnoses entertained. The list
developing countries still do not have access to early included problems of the ears as well as problems of the
identification of hearing loss [13-15]. This problem is nose and throat. The range of pathology included
compounded by paucity of data to facilitate planning and congenital, inflammatory as well as neoplastic problems.
to deal effectively with this complex problem. This study Tables 3 and 4 show the degrees of hearing loss
therefore examined the prevalence and patterns of hearing exhibited by subjects' ear. Table 3 shows the distribution
loss among the children who presented for hearing according to the severity of hearing loss while Table 4
assessment in the ear clinics of the University College shows the distribution according to the presence or
Hospital, Ibadan, Nigeria and LAUTECH Teaching absence of disability. Slightly more than a quarter (27.5%)
Hospital, Osogbo, two teaching hospitals that serve much of the assessed children had normal hearing, 64.6% of
of south-western Nigeria. right ears exhibited hearing loss and 53.5% of the left ears
had hearing loss. This means that 64.6 % of the children
MATERIALS AND METHODS tested had hearing loss in at least one ear. Disabling
hearing   loss  was  found  in  56.7%  of  right  ears  and
This was an institutionally approved cross-sectional 47.2% of left ears. Overall, 90.2% of those who had
study  of   children  presented  for  hearing  assessment. hearing loss had disabling hearing loss.
A  minimum  sample  size   of   125   was   determined   and
127 consecutive patients who matched inclusion criteria Table 1: Age distribution of the studied subjects
in study  institutions  were   recruited   into   the   study. Age (Years) Frequency Percent
They included all children between the ages 5 and 15 who 5-10 years 64 50.4
presented for hearing assessment and were able to 11-15 years 63 49.6
cooperate with the test procedures but excluded those Total 127 100.0
with discharging ears and those with congenital ear Table 2: Diagnostic profile of studied patients 
malformations like absence of the ear canal. Calibrated Diagnosis Frequency  Percent
audiometers were used to determine the pure tone Chronic Suppurative Otitis Media 26 20.5
audiometric thresholds in a sound-proof booth and Nasal blockage 7 5.5
tympanometers (also calibrated) for the impedance testing Post measles hearing loss 6 4.7
of the ears. These procedures were carried out by certified Adenoid enlargement 4 3.1
audiologists on both ears in each patient. The test results Mental retardation 2 1.6
for pure tone audiometry were configured (charted) on Hard of hearing 45 35.4
wax impaction 10 7.9
audiograms (graphs of intensity against frequency of Otalgia 8 6.3
sound) and the degree, type and pattern of hearing loss Cerebellopontine angle cyst 1 0.8
were noted. Tympanometry results were also charted on Cerebral palsy 1 0.8
tympanograms, graphic representations of the Congenital hearing loss 5 3.9
relationship of external auditory canal air pressure to Chronic non suppurative otitis media 1 0.8
impedance and the type (classified on the basis of the Sudden hearing loss 3 2.4
configuration as Type A, Type AD, Type AS, Type B and Eustachian tube dysfunction 1 0.8
Microtia 1 0.8
Type  C)   was  noted  for  each  patient.   Data   entry, Road traffic accident 2 1.6
cleaning and analysis were done with the Statistical Post nasal space mass 1 0.8
Package for the Social Sciences (SPSS) version 15. Data Bloody otorrhoea 1 0.8
analysis was univariate (proportions, means and standard Cleft palate 1 0.8
deviations, medians and ranges) and results were Cranofacial abnormality 1 0.8
presented as frequency distributions. Total 127 100.0
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Table 3: Profile of Severity of Hearing Loss in examined ears Table 5: Types of hearing loss 
Degree of Hearing Loss Frequency Percent Types of Hearing Loss Frequency Percent
Right Normal Hearing 45 35.4 Right Normal 45 35.4
Mild 18 14.2 Conductive 34 26.8
Moderate 13 10.2 Sensorineural 30 23.6
Moderately-severe 30 23.6 Mixed 18 14.2
Severe 12 9.4 Total 127 100.0
Profound 9 7.1 Left Normal 59 46.5
Total 127 100.0 Conductive 19 15.0
Left Normal Hearing 59 46.5 Sensorineural 35 27.6
Mild 15 11.8 Mixed 14 11.0
Moderate 11 8.7 Total 127 100.0
Moderately-severe 17 13.4
Severe 11 8.7 Table 6: Audiometric patterns of examined subjects
Profound 14 11.0 Patterns of Hearing Frequency Percent
Total 127 100.0 Right Normal 45 35.4
Both Both Ears Normal 35 27.5 Flat 35 27.6
Trough 18 14.2
At least Mild Loss in Both Ears 57 44.9
Peaked 16 12.6
Only Left Ear Normal 24 18.9
Notched 3 2.4
Only Right Ear Normal 11 8.7
Precipitous 5 3.9
Total 127 100.0 Low frequency HL 1 0.8
Others* 4 3.1
Table 4: Profile of hearing loss in examined ears (Showing presence or Total 127 100.0
absence of disability) Left Normal 58 45.7
Degree of Hearing Loss Frequency Percent Flat 27 21.3
Right 0-25 dB (Normal hearing) 46 36.2 Trough 16 12.6
26-30 dB (Mild loss, not disabling) 9 7.1 Peaked 15 11.8
>30 dB (Disabling loss) 72 56.7 Notched 1 0.8
Total 127 100.0 Precipitous 5 3.9
Left 0-25 dB (Normal hearing) 59 46.5 Others* 5 3.9
26-30 dB (Mild loss, not disabling) 8 6.3 Total 127 100.0
>30 dB (Disabling loss) 60 47.2 * Criteria for inclusion in any other category not met.
Total 127 100.0
Table 7: Patterns of tympanograms of examined subjects
0Both Normal 35 27.6
Disabling 83 65.3 Patttern of Tympanogram Frequency Percent
Not Disabling 9 7.1 Right Type A-Normal 66 52.0
Type B-Flat 44 34.6
Total 127 100.0
Type As-Shallow 13 10.2
Type C-ETD 4 3.1
Hearing loss of both conductive and sensorineural
Total 127 100.0
types as well as the mixed form (combining both
Left Type A-Normal 70 55.1
conductive and sensorineural types) were found in both Type B-Flat 39 30.7
ears. In the right ear, the most common type found Type As-Shallow 16 12.6
(26.8%) was the conductive type, although the Type C-ETD 2 1.6
sensorineural   type   was   almost   as   common   (23.6%). Total 127 100.0
In the left ears, the sensorineural type was the commonest
type, the proportion (27.6%) almost doubling that for the flat type. The trough and peak types were also
conductive hearing loss (15%) (Table 5). frequently  encountered   though   not   as   commonly.
Table 6 shows the audiometric patterns that were Other   known  patterns  of  audiograms  were  also  found.
found. Apart from the normal pattern that was found in A few audiograms did not meet the criteria for inclusion in
the normal ears, the predominant pattern for both ears was any  other   category.   Table   7   shows  the    distribution
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of   the    patterns     of     the     tympanograms     found. of hearing loss  may  not   be   on   a   list   of   priorities.
The predominant pattern for both ears was the normal This situation is unfortunately rather paradoxical since it
pattern.    Among   those  with  hearing   loss,   however, has been shown that economic losses from a high
the predominant pattern was the flat type. prevalence of hearing loss in the community is actually
very high [20]. There is therefore a need for very strong
DISCUSSION advocacy to bring to light the true situation of hearing
loss in our communities and to show that we could
Majority (72.5%) of the children aged 5-15 years who actually make economic gains on the long run if the
presented for hearing assessment in our study were sent prevention, detection, treatment and rehabilitation of
in for a wide variety of reasons. Most of them were hearing loss in children are paid more attention in our
diagnosed     as    having   hearing   loss   and  in   90.2% health programs.
of those with hearing loss, the loss was disabling. Further supporting the likelihood that the prevalence
Although conductive hearing loss was the predominant figures available may be underestimating the true
type on the right and sensorineural hearing loss on the prevalence of hearing loss in the community is the fact
left, overall, sensorineural hearing loss was the most that our study was conducted on children with a wide
prevalent. The flat audiogram was the most common and variety of diagnoses and not only on children presenting
the flat tympanogram (Type B) predominated other with hearing loss. Many of the patients did not complain
patterns of middle ear pathology. of hearing loss. It is true that the patients presented with
A prevalence as high as we found in this study problems in systems that are closely associated with the
(72.5%) is much higher than those reported in literature. auditory systems which may lead to hearing loss. But it is
Some community based studies have suggested the also true that such problems exist in abundance in the
prevalence of hearing loss among children in Nigeria community  and  since the   patients   may   not   present
ranges  from  6.7  to  8.9%   [16]   and   a   prevalence   of with overt hearing loss, the hearing  loss  may be
11.3% has been given from another study [18]. Our study overlooked. It has been noted that a vast number of
was conducted in an ear clinic and gave the prevalence of children in our environment do have mild hearing loss
hearing among children presenting for hearing which may not be noticed  and  therefore  may  not
assessment, not the community prevalence. It is however present  on  time  [21]. This further emphasizes the
pertinent to note that some of the previous community importance of vigilance and maintenance of a high index
based studies were based on segments of the population of suspicion among health workers and other
of children, for example, children in schools [16] or professionals who deal with children so as to ensure
pediatric clinics and may also not be correct estimates the cases of hearing loss in children as possible are readily
of the true community prevalence. It is reasonable to identified. It also underscores the need for very strong
postulate that the true community prevalence may in fact ear-care programs as part of every tier of our health care
be higher that  what  previous  studies  have   estimated. systems in developing countries. 
This is a plausible situation since in the developing world According to the World Health Organization,
we often only observe a very small proportion of the disabling loss in children aged 0-14 years is defined as the
pathology that actually exists. This so-called 'the tip of presence of a hearing threshold of = 31 dB in the better
the iceberg' phenomenon is in harmony with the situation ear [9]. Going by this criterion, an overwhelming majority
of hearing loss among children in developing countries (nine out of ten) of the children in our study presented
which has been described as "a silent epidemic" and "a with disabling hearing loss. This very significant finding
silent health priority"[19]. raises the volume of our alarm even higher as it suggests
The point that we do emphasize from the high that the majority of the children that we see in our ear
prevalence in our study is that  hospitals  and  ear  clinics clinics with hearing loss may be children who have
in developing countries such as ours and maybe also in disabling loss. It may also mean that children with
the developed world get to see a lot of patients with progressively worsening hearing loss do not present until
hearing loss and they need to be prepared to detect, treat the loss becomes disabling. Both possibilities have grave
and rehabilitate such patients. Governments and health implications for a child. Hearing loss in children has been
authorities should also have strong primary prevention linked with deficits in speech and language acquisition,
programs in place. These measures are particularly poor cognitive development, poor academic performance,
important   in   resource-scarce   developing   countries personal-social maladjustments and emotional difficulties
where such preparation for prevention and management [3].
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Yet another finding of great importance in our study being   exclusively   hospital   patients  has  however,
is the overall preponderance of sensorineural hearing loss provided an opportunity to gain valuable insight into the
in the ears of the children tested. Previous studies have patterns of hearing loss in this population. The exclusion
suggested that the conductive type of hearing loss is the of children aged less than five years, due to the fact that
commonest type of hearing loss among children [22]. these children could not cooperate with pure tone
Hearing loss of the conductive type is due to problems of audiometry instructions, leaves a gap in the data
the external and middle ears [23]. Middle ear infections are concerning children of this age group. This excluded age
particularly common in children and if recognized can group is significant since children in the group are
usually be successfully treated [24]. In our study, particularly  vulnerable  to  the  effects  of  hearing  loss.
conductive hearing loss was indeed responsible for a Our recommendations for further studies include
large number of the cases, underscoring the need for community based household studies and studies that
programs directed at preventing and identifying such utilize methods (such as auditory brainstem response
cases for early intervention. But there were more ears with audiometry and otoacoustic emissions technology) that
sensorineural hearing loss. Sensorineural hearing loss, that can be used for children under five.
unlike conductive is usually irreversible and the emphasis In order to reduce the huge burden that hearing loss
is on rehabilitation. Permanent congenital and early-onset places on this special group, especially in developing
hearing loss (PCEHL) is also very common in children and countries like ours, we recommend that many more new
it is of paramount importance that these cases also be programs be created and existing programs strengthened
detected and rehabilitated [21, 25, 26]. to empower health workers and other professionals who
There is therefore evidence from literature that both work with children including teachers to identify children
types of hearing loss existed in children in large enough with hearing loss and other ear diseases early and to refer
amounts to justify readiness for the management of both them promptly. 
types. Unfortunately, in our environment, facilities for
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