Screening helps identify conditions in healthy individuals for early detection and intervention. Universal neonatal hearing screening aims to detect hearing loss early in all newborns, promoting timely treatment for optimal development. It is not a diagnostic tool, but it helps identify cases requiring further evaluation.

Hearing is essential for language and overall development. Hearing loss can impair language, speech, and social skills, impacting a child's growth. Early intervention reduces these effects on social, emotional, and intellectual development.

In India, 0.60% of children aged 0-4 have hearing loss, higher than other disabilities (0.32%) 1. However, neonatal hearing screening programs are limited, especially in rural areas, due to challenges like a shortage of audiologists and inadequate infrastructure2.

Neonatal hearing screening began in India in the 1970s, with studies like Yathiraj et al. in 2002 exploring effective methods3. In 2006, the National Programme for Prevention and Control of Deafness (NPPCD) aimed to identify severe hearing loss by six months and provide rehabilitation by nine months. The Joint Committee on Infant Hearing (JCIH) recommends screening by one month, diagnosis by three months, and intervention by six months4.

Oto-acoustic Emissions (OAEs) are a reliable and cost-effective method for hearing screening, as they don’t require a behavioral response5.

This topic highlights the importance of early hearing loss detection for children's development and well-being.a

STUDY DESIGN: Cross sectional study

SAMPLE SIZE: 500

INCLUSION CRITERIA:

1. All newborns delivered at Bhaskar General Hospital, Department of Obstetrics and Gynecology.
2. All neonates attending the Department of Pediatrics at Bhaskar General Hospital.
3. All neonates whose parents provide informed written consent for participation in the study.
4. Neonates of gestational ages, including preterm and term, to ensure comprehensive screening across different stages of birth.
5. Neonates without significant congenital abnormalities that could affect hearing, such as craniofacial malformations or syndromic conditions.

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EXCLUSION CRITERIA:

1. Neonates with meatal atresia or congenital abnormalities of the external ear, where the insertion of the probe for oto-acoustic emissions testing is not feasible due to structural abnormalities.
2. Neonates whose parents or guardians do not provide informed written consent for participation in the study.

METHODOLOGY:

This is a one-year cross-sectional study conducted at Bhaskar Medical College & Hospital, Moinabad, to screen the hearing of all newborns delivered at the hospital and neonates attending the facility from January 2019 to December 2019.

Parents of neonates who meet the inclusion criteria will be interviewed regarding maternal and neonatal history, and written informed consent will be obtained. The neonates will then undergo hearing screening using Oto-Acoustic Emissions (OAE) in a soundproof room.

Initially, all neonates will be screened, and their responses will be recorded as either PASS or REFER. The OAE test takes approximately 5 minutes to complete. Follow-up screening will be performed on neonates with a REFER result after one month. If the result remains REFER on the first follow-up, a second screening will be done after another month. If the neonate continues to show REFER results after the third follow-up, a BERA (Brainstem Evoked Response Audiometry) test will be conducted to confirm the diagnosis and assess the type and degree of hearing loss. Routine Ear, Nose, and Throat (ENT) investigations will be conducted if necessary, based on the neonate's medical history and clinical findings.

STATISTICAL ANALYSIS

During this study, 500 neonates born at and attending Bhaskar General Hospital were subjected to Oto-Acoustic Emission (OAE) testing, and the results were analyzed using percentages. The age of the study group ranged from 3 to 90 days. Among the participants, 279 neonates (56%) were male and 221 neonates (44%) were female. The gestational age of the neonates ranged from 30 to 38 weeks, and their birth weight varied from 1000g to 3800g.

At the end of the three-stage screening process, 499 neonates (99.8%) were found to have normal hearing, while 1 neonate (0.2%) had hearing impairment.

• Total neonates screened initially by OAE: 500
• Total neonates who passed the first screening by OAE: 413 (82.6%)
• Total neonates who failed the first screening by OAE and were rescreened: 87 (17.4%)
• Total neonates who passed after the second screening by OAE: 71 (81.6%)
• Total neonates who failed after the second screening by OAE and were rescreened for the third time: 16 (18.4%)
• Total neonates who failed after the third screening by OAE: 1
• Total number of neonates who underwent ABR (Auditory Brainstem Response) testing: 1 (0.2%)
• Only one neonate was diagnosed with hearing impairment after the ABR, resulting in an incidence rate of 0.2%.

TABLE- 1: SEX DISTRIBUTION

Of 500 neonates screened for OAE, 279 males and 221 females were tested. In the first screening, 51 males (18.2%) and 38 females (16.2%) were marked as REFER. In the second, 10 males and 6 females were marked as REFER, and in the third, only 1 male was marked as REFER.

TABLE- 2: FIRST SCREENING BY OAE

After the first screening of 500 neonates, 413 (83%) were marked as PASS and 87 (17%) as REFER. Among the REFER group, 18 (3%) had REFER in one ear, while 69 (14%) had REFER in both ears.

TABLE- 3: SECOND SCREENING BY OAE

Of the 87 neonates with a REFER result in the first screening, 71 passed the second test, while 16 were marked as REFER again. Of these 16, 5 had REFER in one ear and 11 had REFER in both ears.

TABLE- 4: THIRD SCREENING BY OAE

Out of the 16 neonates with a REFER result in the second screening, only one neonate was marked as REFER in both ears during the third screening. This baby was further evaluated by ABR and diagnosed with bilateral profound hearing loss.

TABLE- 5: TYPE OF DELIVERY

Out of 500 neonates studied, 204 were delivered via NVD and 296 via LSCS, with most LSCS performed electively due to previous deliveries, oligomenorrhea, LBW, and twinning. Among the 204 NVD deliveries, 26 (12.7%) were marked as REFER, while 61 (20.6%) of the 296 LSCS deliveries were given a REFER result.

TABLE- 6: TERM VS PRETERM

Out of 500 neonates studied, 492 were term, and 5 were preterm. The preterm deliveries were due to twinning (1 case), abruption placenta (1 case), and pre-eclampsia (2 cases). Of these 5 preterm neonates, only one (20%) was given a B/L REFER result. The baby with a REFER result on the third test was a preterm neonate delivered by NVD due to abruption placenta.

TABLE- 7: TYPE OF MARRIAGE

Out of 500 neonates studied, 77 were born to consanguineous marriages and 423 to non-consanguineous marriages. Among them, 17 (24.2%) neonates from consanguineous marriages and 70 (16.5%) from non-consanguineous marriages were given a REFER result. Only one neonate (1.2%) from a consanguineous marriage received a TEOAE REFER in the third test and was later evaluated by ABR.

TABLE- 8 : BIRTH WEIGHT

In our study of 500 neonates, 49 had low birth weight (LBW), with 7 (14.3%) marked as REFER. Of the 451 neonates with normal birth weight, 80 (17.7%) were marked as REFER. Only one LBW neonate was marked as REFER on the third test.

TABLE-9 FAMILY HISTORY OF HL

In the study of 500 neonates, 7 had a family history of HOH, and 2 (28.5%) were marked as REFER in the first test, both of which passed the second test. Among the 493 neonates without a positive family history, 85 (17.2%) were marked as REFER, with only one diagnosed with hearing impairment.

TABLE- 10: APGAR SCORE

Of the 500 neonates studied, 56 had a low APGAR score, with 15 marked as REFER in the first test. Among the 444 neonates with normal APGAR scores, 72 were marked as REFER. The neonate with a REFER result on the third test had a low APGAR score of 4/1 and 5/5.

The present study evaluated the effectiveness of otoacoustic emissions (OAE) in neonatal hearing screening among 500 neonates at Bhaskar General Hospital. The findings demonstrate a high success rate of OAE screening, with only one neonate ultimately diagnosed with hearing impairment. This aligns with previous studies highlighting OAE as a reliable and efficient screening tool for early detection of neonatal hearing loss5.

Sex distribution analysis showed that male neonates were slightly more likely to fail the initial screening compared to females. However, by the final assessment, both sexes exhibited similar hearing outcomes. This finding is consistent with existing literature suggesting that while initial screening failure may be more common in males, long-term hearing outcomes do not significantly differ between genders 6. 

The mode of delivery appeared to influence the screening outcomes, as neonates born via cesarean section (LSCS) had a higher initial failure rate compared to those born via normal vaginal delivery (NVD). This is in agreement with previous studies suggesting that LSCS neonates may have transient middle ear fluid retention, which can temporarily affect OAE test results. However, subsequent screenings indicated that this factor did not contribute to long-term hearing impairment7. 

Gestational age was another critical factor, as preterm neonates exhibited a higher likelihood of failing the initial screening. However, follow-up screenings indicated that the majority of these neonates eventually passed, suggesting that prematurity may delay auditory system maturation rather than indicate permanent impairment. This is consistent with studies reporting that while preterm neonates are at increased risk for auditory dysfunction, many show normal hearing upon reassessment8. 

Consanguinity has long been recognized as a risk factor for hereditary hearing loss due to the increased probability of autosomal recessive conditions. In this study, neonates born to consanguineous parents showed a slightly higher likelihood of initial screening failure compared to those from non-consanguineous marriages. However, follow-up assessments revealed that consanguinity alone was not a determining factor for permanent hearing impairment, reinforcing the need for genetic screening in high-risk populations9. 

Birth weight analysis revealed that low birth weight (LBW) neonates were initially more likely to fail the screening compared to those with normal birth weight. However, reassessments indicated that most of these neonates eventually demonstrated normal hearing. Previous studies have shown a higher prevalence of hearing impairment in very low birth weight (VLBW) neonates, often due to perinatal complications and prolonged NICU stays, but this study found that LBW alone was not a definitive predictor of permanent hearing loss10. 

A family history of hearing loss was identified in a small subset of neonates. While initial screening failure was more common in this group, follow-up screenings confirmed normal hearing in most cases. This underscores the role of genetic predisposition in congenital hearing loss while also emphasizing the importance of comprehensive follow-up evaluations before concluding a diagnosis11. 

The APGAR score, which assesses neonatal vitality at birth, was another factor influencing screening results. Neonates with lower APGAR scores were more likely to fail the initial screening. However, subsequent screenings indicated that only a small fraction of these neonates had persistent hearing concerns. This finding supports existing research suggesting that while neonatal distress may temporarily impact hearing function, most neonates recover auditory function with time12. 

Overall, the study reinforces the utility of universal neonatal hearing screening using OAE. The high pass rate following multiple screenings highlights the effectiveness of this method in identifying neonates requiring further evaluation. The results also suggest that while factors such as gestational age, mode of delivery, birth weight, family history, and APGAR scores may influence initial screening outcomes, most neonates achieve normal hearing upon reassessment. These findings underscore the importance of timely follow-up and confirmatory testing, ensuring early intervention for the small percentage of neonates with true hearing impairment. 

In this study of 500 neonates, 87 (17%) initially showed TEOAE REFER results in the first screening. This decreased to 16 (3%) in the second screening, and only 1 (0.2%) neonate failed the third screening and was later diagnosed with profound hearing loss via ABR.Out of the 500 neonates, 279 were male and 221 were female. Only 1 (0.3%) male neonate had a REFER result in the third screening.Among the 500 neonates, 204 were delivered by Normal Vaginal Delivery (NVD) and 296 by Cesarean Section (LSCS). Of these, only 1 neonate (0.4%) born via NVD had a REFER result in the third screening.Of the 500 neonates, 5 were preterm. Among these, 1 (20%) neonate had a bilateral REFER result in the third screening.Of the 500 neonates, 77 were born to consanguineous marriages, and 423 were born to non-consanguineous marriages. Only 1 (1.3%) neonate from a consanguineous marriage showed a REFER result in the third screening.Out of 500 neonates, 49 had low birth weight. Among them, 1 (2%) neonate, weighing 1.1 kg, had a REFER result in the third screening.Seven neonates had a family history of hearing loss (HOH), but all 7 passed the second screening.Among the 500 neonates, 56 had low APGAR scores. Of these, 1 neonate (1.7%) with an APGAR score of 4/1 and 5/5 had a REFER result in the third screening. The study confirms the effectiveness of universal neonatal hearing screening using OAE. Hearing screening for all newborns should be mandatory before 3 months, with treatment starting by 6 months. The government should raise awareness, establish audiology clinics at PHCs, and educate parents on the importance of early detection for child development.

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11. American Academy of Pediatrics, Joint Committee on Infant Hearing. "Year 2007 Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs." Pediatrics, vol. 120, no. 4, 2007, pp. 898–921.
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