لخّصلي

Family history has been considered a risk factor for permanent
congenital, delayed onset, or progressive hearing loss by the Joint
Committee on Infant Hearing since 1973 [1–6]. As a result, a family
history of pediatric hearing loss is used to identify children in
neonatal hearing screening and targeted surveillance programs
around the world. Despite this, the validity of family history as a
risk factor for pediatric hearing loss has yet to be fully evaluated. In
consequence of the lack of evidence to support this risk factor, as of
June 2012, a family history of hearing loss was removed from the
risk factor registry in the United Kingdom [7].
In fact,the true validity has been often obscured, as studies have
failed to isolate family history from additional confounding risk
factors. As noted by Cone-Wesson et al. [8] in their comparative
report of data from normally-hearing neonates with data from
hearing-impaired neonates, many subjects had more than one risk factor for pediatric hearing loss. They reported that, although 26.7%
of infants with permanent hearing loss had a family history of
pediatric hearing loss, this risk factor was also present in 6.8% of
infants with normal hearing at the time of assessment. Sutton and
Rowe [9] calculated a similar prevalence of family history in infants
with congenital hearing loss of 26.2%. Another study by Ohl et al.
[10] found a statistically significant relationship between family
history and congenital hearing loss (p-value 0.03). Yet, again, both
of the latter authors remarked that family history was not
examined as a sole risk factor.
Conflicting evidence also exists in relation to the importance of
this risk factor, with most studies using small subject cohorts.
Zamani et al. [11] conducted a cross-sectional investigation of
infants who were referred for diagnostic assessment to Tehran
University of Medical Sciences children’s hospitals between
September 2000 and February 2002. Of these children, 230 were
identified with various risk factors for neonatal hearing loss and 18
were found to have a hearing loss. However, hearing loss was not
detected in any of the children with a positive family history.
Halpern and colleagues [12] also failed to find a relationship
between family history and congenital hearing loss, although this may have been influenced by the study population, which
consisted only of babies admitted to neonatal intensive care units.
Studies by Kountakis et al. [13,14] have also concluded that family
history was not a significant risk factor.
Regardless, a family history of pediatric hearing loss is still
considered a risk factor for both congenital and postnatal hearing
loss [6]. Therefore, other studies have investigated the relationship
in postnatal cohorts. A recent study using data from Queensland
Health’s Healthy Hearing Targeted Surveillance Program found a
statistically significant correlation between family history and
postnatal hearing loss [15]. The researchers noted that family
history had a high yield of 5.3%, with family history present in
46.4% of 56 subjects who developed postnatal hearing loss [15,16].
Another study by Weichbold et al. [17] also aimed to assess the
relationship between various risk factors and postnatal hearing
loss. From a total sample of 23 children with hearing loss, 3 were
identified as having a positive family history. Although this is a
reasonable percentage, it is difficult to draw concrete conclusions
from this study, as the sample size was very small and the
statistical analysis limited. In a similar study, Fortnum and Davis
[18] attempted to ascertain the etiology of hearing loss in 97
children with progressive or late onset hearing loss and determined that genetics were the likely cause in 23.1% of cases.
Although these studies provide some insight into the relationship
between family history and pediatric hearing loss, the variability of
their findings suggests that further research is necessary.
In addition, further research is needed to address another gap in
the literature regarding the characteristics of hearing loss found in
children with a positive family history. The severity of hearing loss
in children can be linked to language development and,
consequently, educational outcomes [19]. Hence, various studies
have attempted to provide information on the audiometric
characteristics of children with risk factors for pediatric hearing
loss. Billings and Kenna [20] isolated each risk factor and assessed
the severity and laterality (unilateral or bilateral) of the hearing
loss identified. They found that, of 36 children with a positive
family history, 26 had bilateral severe to profound loss, 3 had
bilateral mild to moderate loss, and 4 had unilateral severe to
profound losses. Sutton and Rowe [9] also attempted to assess the
degree of hearing losses identified in their study based on the
probable etiology. They found that, of 38 children whose hearing
losses were likely to be of genetic origin, 23 had thresholds >70 dB
HL and 15 had thresholds 70 dB HL. However, these authors did
not note whether these losses were bilateral or unilateral and it
should also be considered that‘genetic’ does not necessarily equate
with parental report of a positive family history. Other studies have
assessed a variety of JCIH risk factors without isolating the results
for each [8,16]. Consequently, further research using large sample
sizes and systematic definitions of specific audiometric characteristics is required. Such knowledge would be useful in optimizing
treatment planning and clinical policy.
Further studies are also needed to examine the nature of the
familial relationship between family members with hearing loss,
as existing literature is particularly sparse. Fortnum and Davis
[18] assessed the relationships between 125 children with
congenital hearing loss and their family members who also had
pediatric hearing loss. They found that 20% of these children had
only their parents affected, 39.2% had only their siblings affected,
14.4% had both parents and siblings affected, and 19.2% had
relatives other than parents and siblings affected. Details about
family history were unavailable for the remaining 7.2% of the
sample. Beswick et al. [15] reported on familial relationships in
postnatal hearing loss but only included the child’s parents and
siblings. Differing definitions of positive family history along
with varied methods of obtaining a child’s history will lead to
different prevalence estimates. Evidence of the nature of familial relationships implicated in both congenital and postnatal
hearing loss may be useful in forming more specific case-history
questions for use in screening processes and may guide screening
programs to identify children at a higher risk of hearing loss due
to such nature.
It is essential that the aforementioned gaps in the current
literature are addressed to determine the validity of family history
as a risk factor for both congenital and postnatal hearing loss.
Various researchers have noted a lack of efficiency in targeted
hearing surveillance programs in Australia and have recommended that comprehensive research be conducted to assess
specific risk factors [16,21]. This should lead to more informed
policy in all aspects of newborn hearing screening. The present
study used data from Queensland Health’s Healthy Hearing
program to assess the relationship between family history as a
reported risk factor and pediatric hearing loss. Specifically, it aimed
to investigate:
The prevalence and yield of family history as a reported risk
factor in children with congenital and postnatal hearing loss,
The audiometric characteristics of hearing loss in children with a
positive family history,
The nature of the familial relationships between family members
with pediatric hearing loss.