Need for neonatal hearing examinations reiterated
MedWire News: Polish researchers have highlighted the importance of hearing examinations in all neonates after their study showed a high rate of sensorineural hearing loss (SNHL) in infants without known risk factors.
"The high percentage (4.9%) of children with SNHL without any risk factors is a cause for concern," say Ireneusz Bielecki and colleagues from the Medical University of Silesia in Katowice.
Furthermore, a known risk factor for hearing loss - ototoxic medication - was only associated with a small percentage of SNHL, despite the high prevalence of its use in the cohort.
The study included 5282 infants born during 2003-2009 with either one or more defined risk factors for hearing loss (n=2986; including familial hearing loss, craniofacial abnormalities, low birth weight [<1500 g], and intensive care in excess of 7 days), or who tested positive twice on the Transient Evoked Otoacoustic Emission (TEOAE) test within the first 2-3 days of life (n=2296).
Hearing loss was defined as unilateral or bilateral hearing loss of 30 db or more.
Overall, SNHL was identified in 240 (4.5%) infants examined, of whom 128 had one or more identifiable risk factors. Conducive hearing loss was apparent in 40 (0.8%) infants, and normal hearing in 5002 (94.7%) of babies.
Of note, almost 5% of babies diagnosed with hearing loss had no identifiable risk factors.
Infants with the highest percentage of SNHL (15.5%) were those who had identified or suspected syndromes associated with hearing loss, while the next highest percentage (11.5%) was observed among infants who were exposed to mechanical ventilation for a period exceeding 5 days, remarks the research team in the International Journal of Pediatric Otorhinolaryngology.
Unexpectedly, a low percentage of SNHL diagnoses (2.9%) were found in infants who received ototoxic medications, despite the fact that it was the most prevalent of all analyzed risk factors for hearing impairment in the group (33.1%).
Finally, as the number of co-existing risk factors increased, so did the probability of SNHL: 3.1-3.5% of those with one or two risk factors had SNHL, compared with 5.4-5.6% of those with two or three risk factors, and 9.5-10.5% in those with five or more risk factors.
The number of children with hearing loss and an absence of risk factors "indicates the importance of Universal Neonatal Hearing Screening," conclude Bielecki et al.
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By Sarah Guy