Key Words
amplification - children - hearing aids - mild hearing loss - unilateral hearing loss
INTRODUCTION
The first intervention tool available for most children with permanent hearing loss
is appropriate amplification. As proposed by [Tomblin et al (2015)], amplification use may be one of the important moderators of the negative impact
of hearing loss on auditory and communication development outcomes. Although amplification
is the standard care for children with moderate and greater hearing loss, decisions
and follow-up for children with bilateral mild or unilateral loss (frequently referred
to as minimal hearing loss) have been less certain ([McKay et al, 2008]; [Fitzpatrick et al, 2010]; [2014]; [Bagatto and Tharpe, 2014]; [Bagatto et al, 2016]). There is a lack of evidence about the effectiveness and use of hearing aids or
any intervention for these children, resulting in some universal hearing screening
programs setting the target definition for screening at moderate hearing loss ([Wood et al, 2015]). However, in programs where mild hearing loss is targeted, the age of diagnosis
has been substantially reduced from school age to <1 to 2 yr of age ([Fitzpatrick et al, 2014]; [Ghogomu et al, 2014]), leading to earlier intervention with amplification.
The problems related to mild bilateral and unilateral hearing loss (MUHL) from a hearing
perspective and consequently, the reasons for consideration of amplification are different.
Unilateral loss results in a binaural hearing deficit, which leads to difficulty with
localization and listening in noise, whereas mild bilateral loss results in a reduction
in access to soft speech, which also affects speech understanding particularly in
the presence of noise. Despite these fundamental differences in the disorders, many
of the problems children experience academically and in communication as well as the
challenges relative to amplification use reported in the literature are remarkably
similar ([Porter et al, 2016]). In our qualitative interviews with parents of preschool children, which included
11 with unilateral and 9 with mild bilateral loss, parents’ discussions of the challenges,
doubts, and questions around the need for and use of amplification were strikingly
similar ([Fitzpatrick et al, 2016]).
Although guidelines for pediatric amplification are well-established for hearing loss
of moderate degree and greater ([King, 2010]; [AAA, 2013]; [Bagatto et al, 2016]), there is some uncertainty about the benefits of amplification for children with
mild loss or unilateral loss. This uncertainty results frequently in consideration
of hearing aids on a case-by-case basis for these children ([McKay et al, 2008]; [Bagatto and Tharpe, 2014]). The overwhelming majority of children with milder losses are eventually fitted
with hearing aids although the gap between diagnosis and amplification recommendation
is longer than for those with more severe loss ([Fitzpatrick et al, 2010]; [2014]; [Walker, Holte, et al, 2015]). Furthermore, considerable clinical indecision and inconsistent hearing aid use
have been reported, suggesting nonuse or inconsistent use in 30–50% of these children
([Davis et al, 2001]; [Reeve, 2005]; [Fitzpatrick et al, 2010]; [2014]). However, most of these data are from children who did not undergo newborn hearing
screening and were identified later in childhood. More recent data from a longitudinal
study that included results for 38 children with mild bilateral loss showed that about
37% of the children used their hearing aids on a full-time basis (>8.3 hr per day),
40% were part-time users, and 23% did not use them ([Walker, Holte, et al, 2015]). There seems to be a tendency to amplify the overwhelming majority of children
with mild bilateral or unilateral loss eventually; that is, there are perceived benefits
from amplification ([Fitzpatrick et al, 2017]). However, further research is needed to determine the advantages of amplification
for this clinical population and to assist in establishing best practices.
Recent research investigating hearing aid use either through data logging in digital
hearing aids or using parent report has drawn attention to the challenges in achieving
consistent amplification use in young children across the full spectrum of severity
of hearing loss ([Jones and Launer, 2011]; [Walker et al, 2013]; [Muñoz and Hill, 2015]; [Muñoz et al, 2015]; [Walker, McCreery, et al, 2015]). [Jones and Launer (2011)] reported an average of 5.5 hr per day of hearing aid use based on objective data
logging records for approximately 5,000 children from birth to 19 yr of age in the
United States with 40% of children in the 0–4 yr age range achieving <4 hr daily hearing
aid use. More recently, [Muñoz et al (2015)], in a survey of 37 families of young children at a mean age of 22 mo, found that
parents reported <5 hr of daily hearing aid use for 31% of children. Using both data
logging and parent report data, [Walker, McCreery, et al (2015)] found substantially higher average hours of use of 10.6 hr (parent report) and 8.4
hr (data logging) per day for 290 children (age 6 mo to 7 yr at start of study) followed
in a longitudinal study. The preschool children with visits documented from 2 to 4
yr of age had an average of 7.6 parent-reported hours of amplification use and 79%
wore their hearing aids >8 hr daily over the study (up to 6 yr of age).
There is also evidence that hearing aid use varies widely depending on factors such
as the listening context, age of the child, degree of hearing loss, and socioeconomic
status ([Moeller et al, 2009]; [Walker et al, 2013]; [Walker, McCreery, et al, 2015]; [Muñoz et al, 2016]). In children with mild to moderate hearing loss, [Moeller et al (2009)] found that only two of seven parents reported that they established consistent hearing
aid use in multiple listening environments before 2 yr of age. Similarly, [Muñoz et al (2015)] reported that car rides were particularly problematic for parents. In some studies,
children with milder degrees of hearing loss showed greater vulnerability to less
hearing aid use ([Walker et al, 2013]; [Muñoz et al, 2014]; [2016]). For example, in a 2013 study on the same cohort described earlier (n = 272, mean
age of 40.51 mo), [Walker et al (2013)] found that more hearing aid use was related to older age, poorer hearing, and higher
maternal education level. Children with hearing loss <50 dB HL used hearing aids about
one hr less daily (9.95 compared with 11.12 parent-reported hours per day) than those
with >50 dB loss. However, in their 2015 study, an examination of factors affecting
hearing aid use trends did not show any association with severity of hearing loss
or maternal education for the preschool group (n = 125; [Walker, McCreery, et al, 2015]).
Taken together, these studies point to the challenges associated with early amplification
use, which is an essential component of intervention in pediatric hearing care. However,
there is still relatively limited information about the specific population of children
with mild hearing loss or unilateral loss and their amplification use in the current
context of screening and early intervention. Yet, combining mild bilateral and unilateral
loss, these children now account for 40–50% of children identified with permanent
hearing loss during the preschool years ([Fitzpatrick et al, 2014]; [Barreira-Nielsen et al, 2016]). The purpose of this study was to examine hearing aid use in a contemporary cohort
of children who were diagnosed with mild bilateral or unilateral hearing loss following
the implementation of newborn hearing screening. We also sought to identify factors
that influence hearing aid use.
METHODS
Design and Setting
The MUHL study is a multicenter longitudinal cohort study investigating developmental
outcomes in preschool-age children with mild bilateral or unilateral hearing loss.
As part of the study, we collected information from parents on amplification recommendations
and use.
Definitions for mild and unilateral hearing loss for this study were adapted from
the National Workshop on Mild Bilateral and Unilateral Hearing Loss (2005): mild bilateral
hearing loss—average pure-tone air conduction thresholds (at 0.5, 1, and 2 kHz) between
20 and 40 dB HL or thresholds >25 dB HL at two or more frequencies greater than 2
kHz; unilateral hearing loss—hearing loss in one ear only with a pure-tone average
≥20 dB HL or >25 dB at two or more frequencies greater than 2 kHz. In this study,
we categorized children as mild bilateral based on hearing levels in the better ear.
In 2002, a province-wide universal newborn hearing screening program, which involves
screening, early communication development, and parent support was implemented in
the province of Ontario, Canada, a province of approximately 11 million people ([Hyde et al, 2004]). The program includes MUHL in the target disorder. In the Ontario program, children
referred from screening undergo diagnostic assessment at a designated pediatric audiology
program. Children who have hearing loss confirmed are seen by an otolaryngologist
to confirm permanent hearing loss and to receive medical clearance for hearing technology,
if applicable. Parents make an informed choice about hearing technology and other
intervention options such as therapy ([Brown and Mackenzie, 2005]). Children continue audiological follow-up at 3 and 6 mo intervals, respectively,
during the first and second year of amplification followed by annual visits for the
first 6 yr ([OMCYS, 2014]). Frequency of therapy is determined by the child’s intervention program. All services
are publicly funded.
Participants
Inclusion criteria for enrolment in the MUHL study included (a) less than age 3 yr
at study enrollment, (b) permanent mild bilateral (better ear) or unilateral hearing
loss, (c) congenital or early onset hearing loss (before age 6 mo), and (d) English
as one of the languages spoken at home. Children with auditory neuropathy spectrum
disorder were excluded from the study as well as those with a diagnosis of severe
developmental delay based on the requirement to complete multiple spoken language
assessments.
Families were enrolled from 2010 to 2015 in the longitudinal project and were recruited
through their clinical providers from three regions in Ontario (Ottawa, Toronto, and
Southern Ontario). Recruitment took place at several different sites, and we were
unable to collect information on how many families were approached. Children entered
the study at various ages between 12 and 36 mo and were followed up to age 4 yr. The
study received ethics approval from the Children’s Hospital of Eastern Ontario (#09-64×)
Research Institute (main study site) and the University of Ottawa (#H10-09-11), and
met ethics requirements for all of the clinical programs that invited families to
participate in the study.
Study Procedures
For this report, our focus is on amplification information collected through parent-completed
questionnaires. For the study, baseline characteristics related to the child and family
were collected through an intake form at study enrollment. Families were asked to
sign a consent form so that details about the diagnosis and degree of hearing loss
as well as amplification recommendations and fitting could be collected from the child’s
audiology program. At enrolment, families were also sent a study-specific intervention
questionnaire with questions about amplification recommendations, amplification use,
hearing health, and therapy services ([Supplemental Appendix S1]). This questionnaire was resent to the families at each annual assessment and they
were invited to update the information between each assessment. Audiogram information
from the child’s clinical program was examined to document any change in hearing over
the course of the study and to confirm parent reports of recommendations for amplification.
For this part of the study on amplification, data were extracted from the intervention
questionnaire related to the section entitled “Your Child’s Amplification,” which
included three questions on amplification recommendations and use ([Supplemental Appendix S1]). As shown in the questionnaire, parents were specifically asked to report whether
their child had amplification recommended (yes, no) and whether it was used (yes,
no), and to identify the amount of use by checking one of the four responses provided:
all day (all waking hours); most of the time (>6 hr); not often (<6 hr); and never.
These categories were somewhat arbitrary and based primarily on the notion that this
study involved young early-identified children and that, after accounting for naptime,
>6 hr was a reasonable estimate for “most of the time.” Data logging information was
not captured during the study. For this observational study, no protocol was in place
to check or modify the child’s hearing instrument(s). As part of the Ontario Infant
Hearing Program protocol, children are followed by a designated audiology clinic with
trained providers who are required to follow the Infant Hearing Program protocol for
fitting and management of amplification ([OMCYS, 2014]).
Information from parent reports was collapsed into four categories to capture amplification
use over the time of the study:
-
Consistent use—children with a recommendation for amplification and consistent use
(all day, most of the time) over the course of the study.
-
Inconsistent use—children with a recommendation for amplification and limited use
(not used some of the time, not often used) over the course of the study.
-
Not used—children with a recommendation for amplification and not used at all during
the study.
-
Not recommended—parents reported no recommendation for amplification.
Data Analysis
Statistical analysis was performed using SPSS Version 24 (IBM Corporation, Armonk,
NY). Baseline characteristics for the participants were summarized with descriptive
statistics and included frequency counts as well as means and standard deviations
or medians and interquartile ranges, as appropriate.
Parents’ report of amplification use during the study was first examined descriptively
and categorized according to parent questionnaire responses into one of four categories:
consistent use, inconsistent use, not used, or not recommended. We also explored descriptively
the pattern of hearing aid use for children who had at least two completed questionnaires
(n = 58) to monitor any change in hearing aid use.
Using logistic regression, we estimated the association between child or family factors
and amplification use. For this analysis, the response categories for those with hearing
aids recommended were first collapsed into two broader options, (a) most or all day
use (category 1 as described earlier) and (b) little or no use (categories 2, 3 described
earlier). Univariate analyses were first carried out to examine the association between
hearing aid use and the following variables: laterality (bilateral versus unilateral),
sex, type of hearing loss (sensorineural or permanent conductive), age at diagnosis
(<6, ≥6 mo), maternal education, and home language. Because of their association with
the variable of interest, laterality, sex, and maternal education were entered into
the regression model. This number of predictors should allow for the estimation of
a valid model ([Peduzzi et al, 1996]). Using χ2 analysis, we also explored whether there was an association between degree of hearing
loss in the worse ear (mild versus >mild) for the bilateral group and in the impaired
ear (mild versus >mild) in the unilateral group and having amplification recommended
or not. Significance was accepted at the p = 0.05 level and all p-values were two-sided.
RESULTS
Clinical Characteristics of Participants
The results reported in the later paragraphsare based on a total of 184 (83.6%) questionnaires
received over the course of the study for the 69 children (36 boys and 33 girls) in
the study. Based on age at enrolment, a total of 220 questionnaires would have been
expected. However, eight families withdrew before study end (12 questionnaires), seven
children were younger than 48 mo at study end (nine questionnaires), and 15 other
questionnaires were not returned at annual follow-up, thus 83.6% (184 of 220) of the
possible questionnaires were received. A total of 11 parents provided one questionnaire,
18—two questionnaires, 23—three questionnaires, and 17—four questionnaires. In addition,
a total of 153 audiology reports were received with at least one report for each child.
Detailed clinical characteristics of the children are reported in [Table 1] for the full group as well as individually according to mild bilateral or unilateral
loss. The sample consisted of 38 (55.1%) children with unilateral and 31 (44.9%) with
bilateral hearing loss at initial diagnosis. The families who agreed to participate
in the study tended to have completed postsecondary education; mean maternal education
level was 17.4 yr (standard deviation = 3.5). As shown, this was an early-identified
cohort with 91.3% (63 of 69) of children having undergone screening. Children were
identified at a median age of 3.6 (interquartile range [IQR] = 2.4, 5.7) mo. The majority
of the children (85.5%, n = 59) presented with congenital loss and an additional four
(5.8%) children had known early onset hearing loss (before age 6 mo). A total of 75.4%
(n = 52) had sensorineural loss. The relatively large number of children with permanent
conductive loss (24.6%, n = 17) is consistent with ear, nose, and throat malformations
(microtia and atresia) as the single largest known etiology, accounting for 21.7%
of known etiologies. Of the 38 children with unilateral loss, 23 (60.5%) had <70 dB
loss in the impaired ear at diagnosis, whereas 15 (39.5%) presented with severe or
profound loss. For the 31 children with bilateral loss, degree of hearing loss in
the worse ear at diagnosis ranged from high frequency only to <70 dB, with the majority
presenting with mild loss (61.3%, n = 19). Based on audiological reports, six children
showed deterioration in hearing at some point during the study.
Table 1
Characteristics of 69 Children with Mild Bilateral or Unilateral Hearing Loss
|
Characteristics
|
Unilateral HL
|
Mild Bilateral HL
|
All
|
|
N
|
38
|
31
|
69
|
|
Sex (male %)
|
23 (60.5%)
|
13 (41.9%)
|
36 (52.2%)
|
|
Maternal education, # yr, mean (standard deviation)[*]
|
17.2 (3.4)
|
17.7 (3.6)
|
17.4 (3.5)
|
|
Screening status
|
|
|
|
|
Screened
|
35 (92.1%)
|
28 (90.3%)
|
63 (91.3%)
|
|
Not screened or unknown status
|
3 (7.9%)
|
3 (9.7%)
|
6 (8.7%)
|
|
Age confirmation, mo, median (IQR)
|
3.4 (2.0, 5.5)
|
3.6 (2.7, 5.9)
|
3.6 (2.4, 5.7)
|
|
Age enrolment, mo, median (IQR)
|
14.2 (9.0, 26.4)
|
19.3 (10.8, 28.1)
|
16.5 (9.5, 26.8)
|
|
Age final assessment, mo, median (IQR)
|
47.8 (38.8, 48.5)
|
48.1 (47.2, 49.3)
|
48.0 (46.2, 48.6)
|
|
Onset of hearing loss, n (%)
|
|
|
|
|
Congenital
|
35 (92.1%)
|
24 (77.4%)
|
59 (85.5%)
|
|
Early onset (<6 mo)
|
0
|
4 (12.9%)
|
4 (5.8%)
|
|
Late onset (>6 mo)
|
2 (5.3%)
|
1 (3.2%)
|
3 (4.3%)
|
|
Unknown
|
1 (2.6%)
|
2 (6.5%)
|
3 (4.3%)
|
|
Type of hearing loss, n (%)
|
|
|
|
|
Sensorineural
|
24 (63.2%)
|
28 (90.3%)
|
52 (75.4%)
|
|
Conductive
|
14 (36.8%)
|
3 (9.7%)
|
17 (24.6%)
|
|
Etiology known
|
|
|
|
|
Neonatal intensive care unit
|
2 (5.3%)
|
0
|
2 (2.9%)
|
|
Hereditary/genetic
|
2 (5.3%)
|
6 (19.4%)
|
8 (11.6%)
|
|
Syndromes
|
1 (2.6%)
|
2 (6.5%)
|
3 (4.3%)
|
|
ENT malformations
|
13 (34.2%)
|
2 (6.5%)
|
15 (21.7%)
|
|
Cytomegalovirus
|
1 (2.6%)
|
1 (3.2%)
|
2 (2.9%)
|
|
Etiology unknown
|
19 (50.0%)
|
20 (64.5%)
|
39 (56.5%)
|
|
Degree of hearing loss at diagnosis (impaired/worse ear)
|
|
|
|
|
High frequency[†]
|
0
|
5 (16.1%)
|
5 (7.2%)
|
|
Mild (20–40 dB HL)
|
3 (7.9%)
|
19 (61.3%)
|
22 (31.9%)
|
|
Moderate (41–55 dB HL)
|
7 (18.4%)
|
4 (12.9%)
|
11 (15.9%)
|
|
Moderately severe (56–70 dB HL)
|
13 (34.2%)
|
3 (9.7%)
|
16 (23.2%)
|
|
Severe (71–90 dB HL)
|
11 (28.9%)
|
0
|
11 (15.9%)
|
|
Profound (>90 dB HL)
|
4 (10.5%)
|
0
|
4 (5.8%)
|
|
Age rec amplif, mo, median (IQR)[‡]
|
6.7 (4.6, 30.0)
|
4.9 (3.2, 14.9)
|
6.5 (3.6, 21.2)
|
|
Age fitting amplif, mo, median (IQR)[§]
|
12.2 (7.2, 29.9)
|
10.5 (5.2, 21.7)
|
10.9 (6.0, 22.1)
|
amplif = amplification; ENT = ear nose throat (anomalies included atresia and microtia);
HL = hearing loss; rec = recommendation.
* Not reported by three families.
† Defined as ≥25 dB HL at ≥2 frequencies above 2 kHz.
‡ Age was available for 27 of 30 children with unilateral hearing loss and for 27 of
29 with mild bilateral loss who received amplification recommendations.
§ Age of fitting was available for 21 of 26 children with unilateral hearing loss and
for 25 of 27 with mild bilateral loss.
Overall Amplification Use
[Figure 1] shows an overall summary of amplification recommendations and use for children with
bilateral and unilateral hearing loss. Overall, 59 of the 69 children (85.5%) received
a recommendation for amplification based on parent and audiologist reports at diagnosis
or during the study. This included 30 of 38 (79.0%) children with unilateral loss
and 29 of 31 (93.6%) with bilateral loss. Amplification was recommended at an early
age at a median of 6.5 mo (IQR = 3.6, 21.2). A total of 53 (89.8%) of the children
who received a recommendation were fitted with amplification (one with frequency modulation
system only) at a median age of 10.9 (6.0, 22.1) mo. Parents of an additional six
children with recommendations for amplification reported that they did not acquire
it.
Figure 1 Amplification recommendations and use for 69 children based on parent report.
Overall, 39 (66.1%) of the 59 children who received amplification recommendations
acquired and achieved consistent use in the preschool years, whereas the remaining
20 (33.9%) had inconsistent use (n = 7) or did not use or acquire amplification at
all (n = 13). A substantially larger proportion of children with mild bilateral loss
(25 of the 29, 86.2%), who had amplification recommended, used it consistently compared
with 14 of the 30 (46.6%) of those with unilateral loss. Although recommended, amplification
was not used at all by 11 of the 38 children (28.9%) with unilateral loss and 2 of
the 29 (6.9%) with bilateral loss.
Trends in Amplification Use
We qualitatively examined trends in hearing aid use over time for 58 children whose
parents provided at least two questionnaires. By the study end, 36 (62.1%) of these
had achieved consistent use and the remaining 22 (37.9%) continued to show inconsistent
or no use based on parent report. In the consistent use group, as shown in [Figure 2], increases in amplification use were seen over time for 8 of the 36 (22.2%) children.
These were eight children whose parents, at the start of the study (first questionnaire),
reported no use (n = 3) or not often used (n = 5). In the inconsistent use group,
only one parent reported a change in use over time, decreasing from most of the time
at 24 mo of age to not often at age 36 and 48 mo. Similarly, in those who had no amplification
use by the study end, no changes were observed over time except for one child who
showed variation across four questionnaires, moving from “not used” to “most of the
time” to “not often” to “not used.”
Figure 2 Change in amplification use from initial to last parent report for children who achieved
consistent use (n = 36).
Factors Affecting Amplification Use
There was no significant difference in consistency of amplification use based on sex
(odds ratio [OR] = 0.52; 95% confidence interval [CI] = 0.15, 1.75) or maternal education
(OR = 1.18; 95% CI = 0.76, 1.84). However, compared with children with unilateral
hearing loss, those with bilateral loss were more likely to use amplification consistently,
that is, they had 6.75 times the odds of consistent use (OR = 6.75; 95% CI = 1.84,
24.8).
We also explored the effect of degree of hearing in the worse ear related to hearing
aid use for the 31 children with mild bilateral loss because poorer hearing in the
worse ear was associated with hearing aid recommendations in our previous research
([Fitzpatrick et al, 2010]; [2014]). There was, however, no significant association with degree of hearing loss (p = 0.38) in the present study. An exploration of the association between having amplification
recommended (yes, no) and degree of hearing loss in the worse ear (mild bilateral
group) or degree in the impaired ear (unilateral loss group) showed no significant
difference for either group (Fisher’s exact test: p = 1.0 for both groups).
DISCUSSION
Early identification of large numbers of children with MUHL is a relatively recent
consequence of the widespread implementation of newborn screening programs. Our findings
showed that clinicians overwhelmingly recommended amplification for these children
regardless of degree or laterality of hearing loss, with 85.5% of all children receiving
recommendations for amplification by the end of our study. Furthermore, on average,
amplification was recommended for these early-identified children at much earlier
ages (on average 6.5 mo of age) than previously documented ([Durieux-Smith et al, 2008]; [Fitzpatrick et al, 2014]). However, 1 in 5 children with unilateral hearing loss did not have any type of
amplification prescribed compared with just 1 in 15 of children with mild bilateral
loss. Although amplification was widely recommended, just two-thirds of parents reported
that consistent use had been established in the preschool years. The problem was particularly
concerning for children with unilateral loss because although amplification was recommended
for 79%, <50% (14 of 30) achieved consistent device use. More than one-third of those
with unilateral loss, who had received recommendations for amplification, reported
not having acquired or used a hearing instrument. By contrast, the majority (86.2%,
25 of 29) of children in the bilateral group consistently used their amplification
and only two families reported total nonuse. An examination of trends in use for all
children suggested that most of the parents either adopted amplification and used
it from the beginning or achieved little or no use over time. For most children, there
was little increase or decrease in the amount of use reported across the study period.
This study adds to the growing body of knowledge ([Martin et al, 2005]; [Moeller et al, 2009]; [Walker et al, 2013]; [Muñoz and Hill, 2015]; [Muñoz et al, 2015]; [Walker, McCreery, et al, 2015]) that has brought greater awareness to the challenges for families in establishing
early amplification use. Of particular importance, this study adds information specific
to an early-identified cohort of children with minimal hearing loss. Comparison with
other studies is somewhat challenging as there are variations in definitions/cut-points
used to define consistency of use. Our overall study results, with one-third of children
showing inconsistent or no amplification use, are similar to those of [Muñoz et al (2015)] where 31% of parents of 37 children (unilateral and bilateral mild-to-severe loss)
reported <5 hr of daily hearing aid use. It is noteworthy that parent-reported use
for children with “minimal” losses in our study was remarkably similar to those for
children across the spectrum of hearing loss. Interestingly, in contrast to our findings,
[Muñoz et al (2014)] found that children (age = 7 mo to 6 yr) with unilateral loss (n = 7) used their
hearing aid more hours than those with mild loss in the better ear (n = 10).
Although [Walker et al (2013)] and [Walker, McCreery, et al (2015)] found higher parent-reported hearing aid use overall (approximately 10 hr daily)
than the aforementioned studies, children with <50 dB loss used amplification less
consistently. In previous research, we found that greater degree of hearing loss in
the worse ear for children with bilateral loss was related to audiologists’ decisions
to amplify ([Fitzpatrick et al, 2010];[ 2014]). However, in the present study, we did not find that having greater than mild loss
in the worse ear affected consistency of use for the 31 children with bilateral loss.
It is possible that the younger age of children in this study and, therefore, shorter
time with hearing aids may have contributed to these different findings. Another possibility
is that clinical practices including counseling have changed and that audiologists
strongly encourage parents to use their child’s hearing aids regardless of degree
of hearing loss. Amplification was recommended for a larger proportion of children
and with a shorter gap between diagnosis and fitting than we have documented in previous
research with older identified children ([Fitzpatrick et al, 2010]; [2014]).
Our findings are also aligned with those of [Moeller et al (2009)] who reported hearing aid use to be highly variable in early-identified children
with mild to moderately severe hearing loss. Our findings did not, however, concur
with these investigators’ results that on average, amplification use became more consistent
during the second year of life. [Walker, McCreery, et al (2015)], who collected information on use from both parent report and data logging values,
also found that most of the 290 children with bilateral mild-to-severe hearing loss
increased use over time, although a minority also decreased use. Likewise, [Muñoz et al (2014)] also reported that hearing aid use increased with age (age = 7 mo to 7 yr) as well
as with more severe hearing loss. For most of the children, we did not observe a change
in the pattern of use over the course of our study, but these children had only reached
a maximum age of 48 mo by the end of the study.
It is important to note that our study population was different from that described
in the reports mentioned earlier as we included only children with mild bilateral
or unilateral hearing loss. It is possible that the auditory benefits of hearing aids
are not as readily observable in these children’s spoken language acquisition and
auditory behavior ([Walker, Holte, et al, 2015]). Most families who reported use may be those who simply “buy in” from the beginning.
Indeed, interviews reported in a previous study with a subset of 20 families from
our study ([Fitzpatrick et al, 2016]) revealed that decision-making and using hearing aids was one of the most confusing
experiences for families. [Walker, McCreery, et al (2015)] found that maternal education influenced trends in hearing aid use. In our study,
we did not detect any significant relationship between maternal education and parent
report of amplification use. However, the small sample size and the fact that most
mothers were university educated may have precluded this finding. Population-based
studies that examine use in children across a broader spectrum of sociodemographic
status may be able to shed light on the association between hearing aid use and parent-education
level.
Considered in the context of reports on large datasets for children across the spectrum
of hearing loss, which showed that 40% of children used hearing aids <40% of the time
([Jones and Launer, 2011]; [Jones and Feilner, 2013]), our results may at first appear encouraging. Based on parent report, two-thirds
of these young children with mild bilateral hearing loss used amplification >6 hr
per day. However, as reported by [Walker et al (2013)], data logging showed that parents seriously underestimated the actual amount of
use. [Walker, Holte, et al (2015)] concluded that improved audibility through full-time or part-time hearing aid use
was associated with better language scores for 38 children (assessed at age 5 or 7
yr) with bilateral slight or mild loss. It is difficult to directly compare our results
on amplification use to this study for several reasons. First, we used different cutoffs
to categorize children. The [Walker, Holte, et al (2015)] study showed that about a third (37%) of children achieved full-time use, but they
used a cutoff of >8.7 hr, whereas we categorized consistent use as >6 hr use. Furthermore,
their documentation of hearing aid use was based mostly on data logging measures,
and we depended solely on parent report. Finally, our study was focused on early-identified
children (median age of 3.6 mo). By contrast, 15 of 38 children in the [Walker, Holte, et al (2015)] study were late-identified at an average age of 45.5 mo. Both these studies suggest
that audiologists recommended amplification for these children, based on the assumption
or measurement of improved audibility. This work, therefore, continues to point to
the need for parent support in helping them to understand the need for hearing aids
and for establishing consistent use with their young children.
A strength of our study is that it provides information on a large group of early-identified
children with minimal loss followed prospectively over several years. It is also an
advantage that children were serviced in different clinical centers within the same
province; therefore, providing a broader representation of this clinical population.
However, like other longitudinal studies of this type, which require voluntary and
long-term commitment, our research tends to be biased toward families of higher socioeconomic
status. Therefore, the findings may not be as readily applicable to families from
more diverse socioeconomic backgrounds.
The study is limited to a broad parent report of hearing aid use as we did not collect
parent report details on hearing aid use across specific environments such as in the
car, in playgroups and in daycare settings. Furthermore, no comparative objective
measurement of amplification use is available as data logging information was not
collected because the study protocol was planned before widespread availability and
application of this option. Previous studies have reported high (0.76) correlations
between data logging and parent report ([Walker et al, 2013]; [Walker, McCreery, et al, 2015]), although 84% of parents overestimated use by an average of >2.3–2.6 hr ([Walker, McCreery, et al, 2015]). This finding suggests that parent report of use is a reasonably reliable measure
despite overestimation of the actual amount of time hearing instruments are worn.
Our MUHL study was an observational study whose primary purpose was to examine auditory
and communication development outcomes in early-identified children. We did not collect
information on the quality of hearing aid fitting or care. As noted previously, all
children with amplification were required to be followed according to protocols established
by the publicly funded provincial program ([OMCYS, 2014]).
The relatively few changes observed over time for children suggest that most parents,
either adopted amplification and used it consistently from the beginning or simply
did not understand or otherwise “buy into” the need for amplification. We were not
able to collect sufficient reliable information about the type and amount of intervention
to glean insights into whether therapy or particular audiological support early in
the intervention process influenced parents’ decisions to use the prescribed amplification.
Further research could help determine whether greater investment from audiology and
early intervention programs in supporting parents to use the amplification could make
a difference. At a minimum, our research suggests that the majority of parents are
unlikely to change their habits related to amplification practices over time. This
finding connects with our previous qualitative research with a subset of parents from
this study who shared their misunderstandings and ambivalent feelings about the benefits
of amplification ([Fitzpatrick et al, 2016]), and are consistent with findings reported from other research with parents ([McCracken et al, 2008]; [Muñoz et al, 2014]). Taken together, these results suggest that when amplification is prescribed, an
upfront investment may be worthwhile. In particular, our study suggests that parents
of children with unilateral hearing loss require considerable support to use amplification
as one-third (11 of 30) did not acquire or use amplification despite the audiological
recommendation. When combined with inconsistent use, this means that more than half
of the children with unilateral loss did not achieve ongoing use of their recommended
amplification.
Given the apparent amount of time invested in managing these children, future research
specifically geared toward achieving a better understanding of the benefits and costs
of amplification and how to support families in their use of devices seems warranted.
As pointed out by [Moeller et al (2009)], improved understanding of the factors that present challenges for hearing aid use
can help shape the type of information and guidance provided to parents. Given that
up to 40–50% of young children are now first identified with minimal loss and prescribed
amplification, it seems that investing in improving our understanding specifically
of factors affecting these families’ ability to use amplification would be worthwhile.
This is of particular importance as many children may not receive or require regular
long-term language intervention sessions like children with more severe loss, whose
parents receive ongoing guidance.
CONCLUSIONS
This study indicates that audiologists now routinely recommend amplification for children
with minimal hearing loss at an early age. However, parent report points to the challenge
of establishing consistent amplification use, as only two-thirds of all children and
less than half of those with unilateral loss reportedly wore their devices on an ongoing
basis. Given that very few children increased amplification use throughout the study,
our findings suggest that the groundwork for improving auditory access through amplification
needs to be laid at the outset if there is an expectation for auditory benefits from
amplification in children with minimal loss, particularly those with unilateral loss.
Although many children may not be enrolled in specific spoken language intervention,
these results highlight the need for intervention that provides some level of specific
parent support to establish amplification use in the early stages of the care process.
Abbreviations
CI:
confidence interval
IQR:
interquartile range
MUHL:
mild bilateral and unilateral hearing loss
OR:
odds ratio
