Contralateral Suppression of Transient-evoked Otoacoustic Emissions in Leisure Noise Exposed Individuals.

Background: Leisure noise may have a significant impact on hearing thresholds and young adults are often exposed to loud music during leisure activities. This behavior puts them at risk of developing noise-induced hearing loss (NIHL). A frequent initial indication of NIHL is reduced hearing acuity at 4 kHz. The objective of the current study was to assess the role of the medial olivocochlear reflex (MOCR) in leisure noise-exposed individuals with and without a 4-kHz notch. Materials and Methods: Audiological evaluation, including pure-tone and immittance audiometry, was performed for 156 college-going, young adults between May 2019 to December 2019. All participants had averaged pure-tone audiometric thresholds within normal limits, bilaterally. Annual individual exposure to personal listening devices (PLDs) was calculated using the Noise Exposure Questionnaire. The participants were then categorized into exposed (with and without audiometric 4 kHz notch) and nonexposed groups. Transient-evoked otoacoustic emission amplitude and its contralateral suppression were measured using linear and nonlinear click stimuli to study the effect of leisure noise exposure on MOCR. Results: A significantly reduced overall contralateral suppression effect in participants exposed to PLD usage (P = 0.01) in both linear and nonlinear modes. On the contrary, significantly increased suppression was observed in linear mode for the 4 kHz frequency band in the PLD-exposed group without an audiometric notch (P = 0.009), possibly suggesting an early biomarker of NIHL. Conclusion: Measuring contralateral suppression of otoacoustic emissions may be an effective tool to detect early NIHL in leisure noise-exposed individuals.

Status of Newborn Hearing Screening Program in the State of Tamil Nadu, India.

Newborn hearing screening in India is gaining momentum and more programs are getting established every year. We need to know their performance levels, strengths and weaknesses to provide suggestions for building effective future programs. The study aimed to report the status of Newborn Hearing Screening (NHS) program in the state of Tamil Nadu, India. A questionnaire on "Newborn Hearing Screening Survey" was developed and sent to 80 sites with NHS facility all over Tamil Nadu, India. The information collected was subjected to descriptive statistical analyses. On a 95% return rate, private sector contribution towards NHS program are the highest and most of the private hospitals have outsourced the NHS program. In most of the sites, audiologists are incharge of the NHS program and carried out the NHS testing. The majority of sites (67.1%) follow selective screening such as high risk factors, doctor's referral and admission at NICU. The preferred testing was TEOAE in the screening program. NHS protocol was found to be variable at each site and for each patient. The time between second screening and diagnostic testing went up to 3-6 months. However, there is a lack of organized system for documenting the program outcome. The result of this study calls the need for wider implementation of UNHS and to introduce a centralised state or local reporting system for documenting and tracking the infants with hearing impairment.