Risk factors associated with hearing loss in infants: an analysis of 5282 referred neonates

Objective

The aim of our study was to evaluate the frequency of risk factors and their influence on - the distribution and manifestation of - hearing loss in infants. The study was conducted at the Department of Laryngology in the Upper Silesian Center for Child Health in Katowice (Poland), as part of the Polish National Universal Neonatal Hearing Screening, conducted from 2003 to 2009.

Materials and methods

The selected population included every newborn that twice tested positive on the transient evoked otoacoustic emission (TEOAE) screening test, as well as all neonates with one or more risk factors as defined by the Joint Committee of Infant Hearing in 2000 (JCIH).The following procedures were used with each neonate: otolaryngological examination (with otoscopy), tympanometry, automated otoacoustic emission (AOAE), and auditory brainstem response (ABR).A total of 5282 infants were examined. Subjects were categorized into two groups: the first group consisted of 2986 (56.53%) neonates with risk factors of hearing loss, while the second group included 2296 (43.47%) neonates without any known risk factors, but who twice tested positive on the TEOAE screening.

Results

Among all infants examined (5282), sensorineural hearing loss (SNHL) was identified in 240 cases (4.54%), and conductive hearing loss (CHL) in 40 cases (0.76%), while normal hearing (NH) appeared in 5002 cases (94.70%).In the first group, SNHL was identified in 128 neonates (4.29%), and CHL in 28 (0.94%), while NH appeared in 2830 (94.78%). The largest percentage of SNHL (15.52%) appeared in children with identified or suspected syndromes associated with hearing loss. The next highest frequency of SNHL was comprised of children subjected to mechanical ventilation for a period in excess of 5 days (11.45%).Only a small percentage (2.86%) of SNHL appeared to be due to the use of ototoxic medications, despite the fact that this factor is the most prevalent (33.13%) of all analyzed risk factors of hearing impairment. After ototoxic medications, the frequencies of risk factors are as follows: premature birth (16.21%); low birth weight (12.04%); intensive care in excess of 7 days (10.64%). Furthermore, as the number of coexisting risk factors increases, the probability of SNHL in infants is seen to also increase. For children with one to four coexisting risk factors, the probability of SNHL ranges from 3.15% to 5.56%; for five or more risk factors the probability nearly doubles.

Conclusion

Our results indicate that syndromes associated with hearing loss and mechanical ventilation for more than 5 days were statistically significant risk factors in the occurrence of hearing loss. The most common risk factors are ototoxic medications, premature birth, low birth weight, and intensive care in excess of 7 days. As the number of risk factors an infant is exposed to grows, the probability of hearing impairment increases. The large percentage of children with sensorineural hearing loss in the absence of any known risk factors demonstrates the necessity of hearing examinations in all neonates.     

An initial overestimation of sensorineural hearing loss in NICU infants after failure on neonatal hearing screening

Objective

Infants admitted to neonatal intensive care units have a higher incidence of significant congenital hearing loss. We classified audiologic diagnoses and follow-up in infants who had been admitted to our neonatal intensive care unit.

Methods

We included all infants admitted to the neonatal intensive care unit at Sophia Children's Hospital between 2004 and 2009 who had been referred for auditory brainstem response measurement after failing neonatal hearing screening with automated auditory brainstem response. We retrospectively analyzed the results of auditory brainstem response measurement.

Results

Between 2004 and 2009 3316 infants admitted to our neonatal intensive care unit had neonatal hearing screening. 103 infants failed neonatal hearing screening: 46 girls and 57 boys. After first auditory brainstem response measurement we found 18% had normal hearing or a minimal hearing loss. The remainder had a type of hearing loss, distributed as follows: 15% conductive, 32% symmetric sensorineural, 14% asymmetric sensorineural, and 21% absent auditory brainstem responses. Repeated auditory brainstem response measurement showed a shift in hearing outcome. The main difference was an improvement from symmetric sensorineural hearing loss to normal hearing. However, in a small percentage of children, the hearing deteriorated.

Conclusions

As many as 58% of infants in this high-risk population who failed the neonatal hearing screening were diagnosed with sensorineural hearing loss or absent auditory brainstem responses. An initial overestimation of sensorineural hearing loss of about 10% was seen at first auditory brainstem response measurement. This may be partially explained by a conductive component that has resolved. Finally, in a small percentage of children the hearing deteriorated.     

The economics of screening infants at risk of hearing impairment: an international analysis

Objective

Hearing impairment in children across the world constitutes a particularly serious obstacle to their optimal development and education, including language acquisition. Around 0.5-6 in every 1000 neonates and infants have congenital or early childhood onset sensorineural deafness or severe-to-profound hearing impairment, with significant consequences. Therefore, early detection is a vitally important element in providing appropriate support for deaf and hearing-impaired babies that will help them enjoy equal opportunities in society alongside all other children. This analysis estimates the costs and effectiveness of various interventions to screen infants at risk of hearing impairment.

Methods

The economic analysis used a decision tree approach to determine the cost-effectiveness of newborn hearing screening strategies. Two unique models were built to capture different strategic screening decisions. Firstly, the cost-effectiveness of universal newborn hearing screening (UNHS) was compared to selective screening of newborns with risk factors. Secondly, the cost-effectiveness of providing a one-stage screening process vs. a two-stage screening process was investigated.

Results

Two countries, the United Kingdom and India, were used as case studies to illustrate the likely cost outcomes associated with the various strategies to diagnose hearing loss in infants. In the UK, the universal strategy incurs a further cost of approximately £2.3 million but detected an extra 63 cases. An incremental cost per case detected of £36,181 was estimated. The estimated economic burden was substantially higher in India when adopting a universal strategy due to the higher baseline prevalence of hearing loss. The one-stage screening strategy accumulated an additional 13,480 and 13,432 extra cases of false-positives, in the UK and India respectively when compared to a two-stage screening strategy. This represented increased costs by approximately £1.3 million and INR 34.6 million.

Conclusions

The cost-effectiveness of a screening intervention was largely dependent upon two key factors. As would be expected, the cost (per patient) of the intervention drives the model substantially, with higher costs leading to higher cost-effectiveness ratios. Likewise, the baseline prevalence (risk) of hearing impairment also affected the results. In scenarios where the baseline risk was low, the intervention was less likely to be cost-effective compared to when the baseline risk was high.     

Threshold prediction in children with sensorioneural hearing loss using the auditory steady-state responses and tone-evoked auditory brain stem response

Objective

The purpose of this study was to compare ASSRs to tone-evoked ABR and to behavioral thresholds obtained on follow-up audiometry at 500, 1000, 2000, and 4000 Hz in infants and young children.

Methods

The study included 17 infants and young children ages between 2 months and 3 years old, with sensorineural hearing loss. The ASSRs thresholds were compared with the tone-evoked ABR thresholds, and with the behavioral thresholds obtained on follow-up audiometry.

Results

The correlation of tone-evoked ABR and ASSRs thresholds at 500, 1000, 2000 and 4000 Hz was 0.91, 0.76, 0.81, 0.89, respectively. ASSRs and behavioral hearing thresholds obtained on follow-up were highly correlated, with Pearson r values exceeding 0.94 at each of the test frequencies.

Conclusions

Multiple ASSRs have strong correlations to tone-evoked ABR and to behavioral thresholds obtained during follow-up in hearing impaired infants and young children. These results might be useful in order to provide further evidence for the use of multiple ASSRs, as an alternative tool to tone-evoked ABR, although further data are still required.     

Risk factors for elevation of ABR threshold in NICU-treated infants

Objective

Several risk factors for hearing impairment among infants treated in the neonatal intensive care unit (NICU) have been reported, but there have been few studies that show the correlation strength between the risk factors in NICU-treated infants and hearing impairment in childhood. The aim of this study was to clarify the relationship between risk factors in NICU-treated infants and a deteriolation of auditory brainstem response (ABR) threshold in their childhood.

Methods

One hundred one NICU-treated infants with ABR threshold of 50 dBnHL or more underwent 2nd ABR test at 20 months after delivery. Multiple regression analysis was performed with ABR threshold change as an objective variable and risk factors as explanatory variables.

Results

Two ABR tests of the 101 infants resulted in that 7 showed an elevation of ABR threshold by 20 dB, 70 showed a drop of ABR threshold by 20 dB, and 24 showed no significant change. Multiple regression analysis revealed that the factors contributing to the elevation of ABR threshold were congenital diaphragmatic hernia, severe respiratory disease, and a high C-reactive protein (CRP) level.

Conclusions

In the infants treated in NICU, an incidence of ABR threshold of 50 dBnHL or more was 9.0%, and 6.9% of the infants with the ABR threshold abnormality showed a significant elevation of ABR threshold in their childhood. Factors significantly related to an elevation of ABR threshold were a history of congenital diaphragmatic hernia, severe respiratory disease, and elevation of CRP. In infants with such factors, periodical examination of hearing is required.     

Etiological diagnosis in the hearing impaired newborn: proposal of a flow chart

Objective

Most industrialized countries have introduced some form of universal newborn hearing screening program. Both identification and rehabilitation of hearing loss in newborns have evolved to an acceptable standard and the need for a standardized etiological protocol is emerging.

Methods

Extensive literature search to determine which investigations can help identifying the cause of congenital hearing loss and how to limit extensive testing in these children by taking into account the most prevalent causes.

Findings

A stepwise approach to detect the cause of hearing loss in children with congenital sensorineural hearing loss was developed.

Conclusion

In general it is advised to first rule out Cx26/Cx30 and infectious causes (cytomegalovirus and, if indicated, toxoplasmosis and rubella), and to preserve more extensive investigations for those children in whom these causes do not explain the hearing loss.     

Auditory function in women with autoimmune inner ear diseases and their offspring

Objective

The precise cause of congenital sensorineural hearing loss (CSNHL) is unclear in many cases. In a previous study we found that offspring from guinea pigs with autoimmune sensorineural hearing loss (ASNHL) exhibited signs of SNHL. Here we studied women with autoimmune inner ear diseases (AIED) and their offspring. Our aim was to determine if autoimmune damage may be one of the causes of CSNHL.

Methods

Thirty-eight pregnant women with AIED were recruited. Thirty-three had ASNHL; one with autoimmune delayed endolymphatic hydrops (ADEH) and four with autoimmune Meniere's disease (AIMD). The following were assessed in all women: audiogram, auditory brain stem response (ABR), otoacoustic emission (OAE), vestibular function test and presence of inner ear antigens. The following were assessed in offspring from these women: OAE, ABR and presence of inner ear antigens.

Results

Five of the 38 children born to women with AIED had SNHL (an incidence much higher than normal). OAEs were not inducible in these children shortly after birth or within 46-100 days after birth. Abnormal ABR findings were apparent in these five children and inner ear antigens were detected in three of the five children (the mother's of these children were also positive for inner ear antigens).

Conclusions

These preliminary findings suggest that the prevalence of congenital ASNHL may be increased in offspring born to women with AIED.     

Audiological chronological findings in children with congenital anomalies of the central nervous system

Objective

To determine the frequency of hearing impairment in children with congenital anomalies of the central nervous system (CNS) by using detailed audiological evaluation methods.

Methods

The patients were 78 children with congenital anomalies of the CNS with a mean age of 29.5 months. They had been observed for a mean period of 38.5 months. Hearing levels were evaluated behavioral observation audiometry (BOA), visual reinforcement audiometry (VRA) and distortion product otoacoustic emissions (DPOAEs) were performed. Auditory brainstem responses (ABRs) and computed tomography (CT) scans of the temporal bone were performed in the cases in which the minimum response levels (MRLs) were above 30 dBHL. All cases were assessed in terms of developmental age.

Results

A total of 14.1% (11/78) of the children with congenital anomalies of the CNS were initially diagnosed with bilateral sensorineural hearing loss (SNHL). However, the hearing levels of nine of them improved by the time of the last diagnosis. Therefore, the patients with bilateral SNHL were only 2.6% (2/78) of the total patients with congenital anomalies of the CNS at last diagnoses. As shown by our results, many children with bilateral SNHL at initial diagnosis showed improved ABR thresholds and behavioral hearing thresholds with age. In this series, the use of hearing aids was arranged for six patients. However, four patients stopped using hearing aids when their hearing threshold levels improved. In two cases, there were no changes in hearing levels and the children continued using hearing aids.

Conclusion

Our results suggest that hearing level recovery can occur in some children with CNS anomalies. Confirmation of hearing loss in children with congenital anomalies of the CNS takes a long time. There are improvements in hearing loss during the observation period. Therefore periodic assessment of hearing is important.     

Prevalence of auditory neuropathy (AN) among infants and young children with severe to profound hearing loss

Auditory neuropathy is a challenging disorder and needs special habilitative/rehabilitative approach. This study aimed to detect its prevalence among infants and young children with severe to profound hearing loss. 112 infants and young children with age ranged 6-32 months were examined and diagnosed as having severe to profound hearing loss and were referred for hearing aid fitting. Those infants were reassessed in our centers for detecting cases with auditory neuropathy. The study group was subjected to immittancemetry, behavioral observation audiometry, ABR and cochlear microphonics.

Results

15 patients were found to have auditory neuropathy according to our criteria for diagnosis.

Conclusions

The prevalence of AN in the study group was 13.4%. CM were recommended to be tested routinely during ABR assessment whenever abnormal results are obtained.     

Sensorineural deafness in Tanzanian children—Is ototoxicity a significant cause? A pilot study

Objectives

9 years experience working in Tanzania revealed a surprisingly large population of profoundly deaf children. The object was to identify the cause.

Methods

200 children between the ages of 5-12 with significant sensorineural hearing loss were identified in Stone town, Zanzibar. These were aged and neighbourhood matched with 218 normal hearing children.A parental questionnaire administered by health workers from the Zanzibar Outreach Programme was used to interview parents of the matched group of deaf and normal hearing children. Outcome measures included the genetic history especially first cousin marriage (common in Zanzibar), rubella, head injury, fever admission, and drug treatment of fever.The limitations were lack of hospital records and it was a retrospective study. The results were analysed from Excel spreadsheets.

Results

36% of the deaf group had an infant fever admission history compared with 4% of the normal hearing group. Nearly all had i.m. quinine and/or gentamicin. The genetic history was equal in both groups, and rubella was rare. Most fevers were assumed to be malaria or pneumonia which are unlikely causes of deafness on their own.

Conclusions

Ototoxic drugs given to sick infants with “fever”, without weight recording or gentamicin level monitoring, was the probable cause of a third of all severe/profound deafened Zanzibarian children.The Ministry of Health and Social Welfare in Zanzibar have reacted by issuing posters to all health facilities advising hearing testing in all children three months after discharge following “fever” admission.This is a pilot study and the apparent findings need to be confirmed by a well designed prospective study as soon as possible.     

Central auditory nervous system dysfunction in infants with non-syndromic cleft lip and/or palate

Objective

Peripheral hearing loss has been commonly reported in children with non-syndromic cleft lip and/or palate (NSCLP) but few studies have provided information about central auditory nervous system (CANS) functioning for this group. The main objective of this study was to explore CANS functioning in infants with NSCLP through analysis of auditory evoked potentials (AEPs).

Methods

AEPs including auditory brainstem response (ABR), middle latency response (MLR), and mismatch negativity (MMN) recordings were conducted in 34 infants of Chinese ethnicity with NSCLP and an equivalent number of normal controls.

Results

There was no significant difference in ABR (all measurements, including wave I, III, V latencies, I-V inter-wave latency, and wave V amplitude), or MLR (recordable components, Na, Pa latencies, and Na-Pa amplitude) findings between the two groups. However, infants with NSCLP had a significantly smaller MMN response than their normal controls, using MMN strength as the measurement.

Conclusions

Significant abnormal auditory evoked potential findings at the cortical level suggest that infants with NSCLP may be at risk of central auditory discrimination dysfunction. Further effort is needed to determine auditory processing abilities in infants with NSCLP.     

The audiological characteristics of a hereditary Y-linked hearing loss in a Chinese ethnic Tujia pedigree

Objective

To investigate audiometric characteristics of hearing loss in a large Chinese ethnic Tujia family and determine its hereditary type.

Methods

Total 76 live individuals were investigated in the notable 84 members of this family. The detailed audiometric evaluations were undertaken for the proband and his 47 family members. The degrees of sensorineural hearing impairment were defined as an air/bone gap <15 dB hearing loss averaged over 0.5, 1 and 2 kHz. The severity of hearing loss was established based on the hearing ability of the better ear, averaged over 0.5, 1, 2 and 4 kHz, and classified into four categories: mild, moderate, severe and profound.

Results

Nineteen patrilineal relatives of the 76 live members had hearing impairment. The age of onset ranged from 7 to 21 years old with the average of 13.2 years. The audiometric defect was described by auditory curves of a high frequency in 47% of the patients. Affected members in this family demonstrated a non-syndromic, late onset, bilateral, symmetrical, postlingual and sensorineural hearing loss.

Conclusions

The audiometric configuration in males of the pedigree is consistent with the hereditary Y-linked hearing loss. Thus we speculate that a putative gene on the Y chromosome could contribute to the cause of the disease.     

Place of birth and characteristics of infants with congenital and early-onset hearing loss in a developing country

Objective

To determine the characteristics of infants with sensorineural hearing loss (SNHL) and the relationship with place of birth.

Methods

Subjects were drawn from hospital-based and community-based universal infant hearing screening programs concurrently conducted from May 2005 to April 2008 in Lagos, Nigeria. Maternal and infant characteristics of children born in hospitals and detected with SNHL were compared with those born outside hospitals. Each program consisted of a first-stage screening with transient-evoked otoacoustic emissions (TEOAE) followed by second-stage automated auditory brainstem response (AABR). Hearing status was confirmed by diagnostic auditory brainstem response, tympanometry and visual response audiometry.

Results

A total of 4718 infants were screened under the hospital-based program out of which 12 (0.3%) infants were confirmed with SNHL whereas 71 (1.0%) of the 7179 infants screened under the community-based program were confirmed with SNHL. Of all infants with SNHL 39 (47.0%) were born in hospitals suggesting that 27 (38.0%) of infants under the community-based program were born in hospitals. Prevalence of SNHL ranged from 4.0 per 1000 among infants born in government hospitals to 23 per 1000 among those born in family homes. Mothers of those born outside hospitals were significantly likely to belong to the Yoruba tribe (p < 0.001), use herbal medications in pregnancy (p < 0.001), deliver vaginally (p = 0.004) but without skilled attendants at delivery (p < 0.001). There were no significant differences among the infants themselves except that those born outside hospitals were significantly likely to be detected in the first 3 months of life compared to those born in hospitals (p < 0.001).

Conclusions

A significant proportion of infants with SNHL in many developing countries are likely to be born outside hospitals thus underscoring the need for community-oriented UNHS to facilitate early detection and intervention. Conventional risk factors for SNHL are unlikely to discriminate across places of birth. Pediatricians and otolaryngologists should consider a more active role in fostering community-oriented delivery of primary ear care services in this and similar settings in the developing world.     

Prevalence of A1555G mitochondrial mutation in Chinese newborns and the correlation with neonatal hearing screening

Objective

To investigate the feasibility of genetic screening for deafness causative genes in the process of newborn hearing screening in China.

Methods

Total 865 newborn babies between November 2009 and March 2010 were enrolled for the simultaneous hearing and deafness causative gene screening in Tongji Hospital, Wuhan, China. Hearing screening followed a two-stage strategy with transient evoked otoacoustic emissions. Infants referred after the second-stage screening were tested by diagnostic auditory brainstem response (ABR). Genomic DNA was extracted from heel blood of newborns, and the mitochondrial 12S rRNA A1555G mutation was detected by polymerase chain reaction (PCR) based restriction fragment length polymorphism and confirmed by DNA sequencing.

Results

In hearing screening, 134 out of the 865 newborns (15.5%) were referred after the first-stage screening and 86.6% (116/134) of them returned for the second stage. After the second-stage screening, 15 who were still referred were tested by diagnostic ABR and 3 of them failed the test. On the other hand, gene screening identified 6 of the 865 newborns (0.7%) harbored homoplasmic 12S rRNA A1555G mutation although they passed the hearing screening.

Conclusion

It might be practical and effective to complement routine hearing screening in newborns with gene screening for the purpose of early diagnosis and discovery of the late-onset hearing loss.     

Risk factors for sensorineural hearing loss in NICU infants compared to normal hearing NICU controls

Objectives

To evaluate independent etiologic factors associated with sensorineural hearing loss in infants who have been admitted to the neonatal intensive care unit compared to normal hearing controls.

Method

Between 2004 and 2009, 3366 infants were admitted to the neonatal intensive care unit of Sophia Children's Hospital, of which 3316 were screened with AABR. A total of 103 infants were referred for auditory brainstem response analysis after failure on neonatal hearing screening. We included all infants diagnosed with sensorineural hearing loss. Each patient was matched with two normal hearing controls from the neonatal intensive care unit of the same gender and postconceptional age.The following risk factors were studied: birth weight, dysmorphic features, APGAR scores (at 1, 5 and 10 min), respiratory distress (IRDS), CMV infection, sepsis, meningitis, cerebral bleeding, cerebral infarction, hyperbilirubinemia requiring phototherapy, peak total bilirubin level, furosemide, dexamethason, vancomycin, gentamycin and tobramycin administration.

Results

Fifty-eight infants were diagnosed with sensorineural hearing loss: 26 girls and 32 boys. The incidence of dysmorphic features (P = 0.000), low APGAR score (1 min) (P = 0.01), sepsis (P = 0.003), meningitis (P = 0.013), cerebral bleeding (P = 0.016) and cerebral infarction (P = 0.000) were significantly increased in infants with sensorineural hearing loss compared to normal hearing controls (n = 116).

Conclusion

Dysmorphic features, low APGAR scores at 1 min, sepsis, meningitis, cerebral bleeding and cerebral infarction are associated with sensorineural hearing loss independent of neonatal intensive care unit admittance.     

Exploring factors that affect the age of cochlear implantation in children

Objective

Early access to sound through early cochlear implantation has been widely advocated for children who do not derive sufficient benefit from acoustic amplification. Early identification through newborn hearing screening should lead to earlier intervention including earlier cochlear implantation when appropriate. Despite earlier diagnosis and the trend towards early implantation, many children are still implanted well into their preschool years. The purpose of this study was to examine the factors that affected late cochlear implantation in children with early onset permanent sensorineural hearing loss.

Methods

Data were examined for 43 children with cochlear implants who were part of a group of 71 children with hearing loss enrolled in a Canadian outcomes study. Eighteen (41.9%) of the 43 children were identified through newborn screening and 25 (58.1%) through medical referral to audiology. Medical chart data were examined to determine age of hearing loss diagnosis, age at cochlear implant candidacy, and age at cochlear implantation. Detailed reviews were conducted to identify the factors that resulted in implantation more than 12 months after hearing loss confirmation.

Results

The median age of diagnosis of hearing loss for all 43 children was 9.0 (IQR: 5.1, 15.8) months and a median of 9.1 (IQR: 5.6, 26.8) months elapsed between diagnosis and unilateral cochlear implantation. The median age at identification for the screened groups was 3.3 months (IQR: 1.4, 7.1) but age at implantation (median 15.8 months: IQR: 5.6, 37.1) was highly variable. Eighteen of 43 children (41.9%) received a cochlear implant more than 12 months after initial hearing loss diagnosis. For many children, diagnosis of hearing loss was not equivalent to the determination of cochlear implant candidacy. Detailed reviews of audiologic profiles and study data indicated that late implantation could be accounted for primarily by progressive hearing loss (11 children), complex medical conditions (4 children) and other miscellaneous factors (3 children).

Conclusions

This study suggests that a substantial number of children will continue to receive cochlear implants well beyond their first birthday primarily due to progressive hearing loss. In addition, other medical conditions may contribute to delayed decisions in pediatric cochlear implantation.     

Screening for delayed-onset hearing loss in preschool children who previously passed the newborn hearing screening

Objective

The goal of this study was to investigate the prevalence of delayed-onset hearing loss in preschool children who previously passed newborn hearing screening in Shanghai, China.

Methods

Between October 2009 and September 2010, 21,427 preschool children were enrolled from five areas of Shanghai, who had passed newborn hearing screening. Children were screened for delayed-onset hearing loss with pediatric audiometers. Children with positive results in initial and re-screening tests were assessed audiologically and for risk indicators according to the Year 2007 Statement of the American Joint Committee on Infant Hearing (JCIH).

Results

During the study period, 445 children (2.08%) were referred for audiologic assessment; 16 (0.75/1000, 95% CI 0.38-1.12) had permanent delayed-onset hearing loss. Of these, five (0.23/1000) had bilateral moderate hearing loss; seven (0.33/1000) had mild bilateral hearing loss; and four (0.19/1000) had unilateral moderate or mild hearing loss. JCIH risk indicators were established for six children (6/16, 37.5%), including parental concern regarding speech and language developmental delay, neonatal intensive care unit with assisted ventilation or hyperbilirubinemia, recurrent otitis media with effusion, craniofacial malformation, and family history (n = 1 for each). The remaining ten (62.5%) had no related risk factors.

Conclusions

A significant proportion of preschool children have undiagnosed delayed-onset hearing loss. Hearing screening in preschool is recommended for an early detection.     

The role of dyslipidemia in sensorineural hearing loss in children

Objective

The relationship between dyslipidemia and hearing is controversial; especially in children, the available evidences are scarce. This study is designed to determine whether dyslipidemia is associated with sensorineural hearing loss in a group of 5-18-year-old children and adolescents.

Methods

Through an analytic cross-sectional study, records of all 5-18-year-old children who attended the pediatric endocrinology clinic of Loghman Hospital in Tehran, Iran, between April 2007 and April 2009 were reviewed. Records with a lipid profile were determined. Lipid profiles were repeated for eligible cases; they were enrolled if the results were the same as before (normal or dyslipidemic). Hearing loss, speech discrimination scores and lipid profiles were analyzed.

Results

When controlled for age and sex, no association between dyslipidemia and sensorineural hearing loss were found. There was also no statistically significant relationship between dyslipidemia and sensorineural hearing loss in different age groups.

Conclusions

Dyslipidemia seems to have no association with sensorineural hearing loss in 5-18 years old children according to this study.