External and middle ear effects on infant hearing screening test results

Area of Science:

• Audiology
• Neonatal Medicine
• Otolaryngology

Background:

• Newborn hearing screening is crucial for early detection of hearing impairment.
• Automated auditory brain stem response (ABR) and transient-evoked otoacoustic emissions (EOAEs) are common screening methods.
• External and middle ear conditions can affect screening outcomes.

Purpose of the Study:

• To investigate the impact of external and middle ear factors on ABR and EOAE hearing screening results in newborns.
• To determine the effectiveness of clearing occluding vernix on screening pass rates.
• To assess the influence of tympanic membrane mobility on ABR and EOAE outcomes.

Main Methods:

• Screening of 200 healthy newborns (5-48 hours old) using ABR and EOAE.
• Otoscopic examination to assess external and middle ear conditions, including vernix presence and tympanic membrane mobility.
• Comparison of screening results before and after vernix removal.

Main Results:

• Initial ABR and EOAE pass rates were 91% and 58.5%.
• Occluding vernix was present in 28% of ears; its removal increased ABR and EOAE pass rates to 96% and 69%.
• Decreased tympanic membrane mobility affected EOAEs (33.4% pass) but not significantly ABR (95% pass).

Conclusions:

• Clearing vernix is essential for accurate newborn hearing screening.
• Automated ABR is less affected by middle ear effusion or decreased tympanic membrane mobility compared to EOAEs.
• Addressing external ear canal obstructions improves the reliability of neonatal hearing screening programs.