Measures to detect newborn and infant hearing impairment effective
MedWire News: Current scientific evidence supports the use of universal neonatal hearing screening (UNHS) plus an observation program to detect early childhood hearing impairment and aid language development in hearing-impaired children.
Universal neonatal hearing screening is the standard for diagnosing hearing disorders in newborns and infants in Europe, the USA, and parts of Asia. Martin Ptok (Klinik und Poliklinik für Phoniatrie und Pädaudiologie, Medizinische Hochschule Hannover, Germany) conducted a literature review to determine whether screening can determine a child's type and degree of hearing impairment.
As reported in Deutsches Ärzteblatt International, Ptok carried out a selective search of five prominent databases. Confining the data to clinical or comparative trial results published between 2007 and 2010, Ptok identified 379 evaluable studies.
The two detection tools for UNHS - otoacoustic emission measurement and automated auditory brainstem response (AABR) audiometry - are often difficult to perform and the sensitivity can be variable. Varying figures on UNHS coverage are reported in the literature, depending on whether the country or state has mandatory screening for all newborns.
Selective screening of newborns with specific risk factors has been discussed as an alternative to UNHS. Children who have one or more of these factors have nearly a 10-fold greater risk for developing a hearing impairment requiring treatment than those with no risk factors (1-2 vs 0.1-0.2%). However, since nearly 50% of all hearing-impaired children do not have any risk factors, selective screening is not recommended. Newborns with specific risk factors should be referred for immediate AABR screening or have a confirmatory diagnostic evaluation.
For UNHS to be effective, a hearing disorder diagnosis must be confirmed and treatment started as early as possible, and speech acquisition and development must be recognizably better in children who received early diagnosis and treatment than in those with a later diagnosis.
To date, there have been no relevant prospective randomized trials to measure this, but cohorts with and without UNHS have been compared. These have shown that there has been a trend toward better and earlier speech development in children who were in a UNHS program. Few disadvantages of UNHS have been noted in the literature.
If UNHS indicates that a child may be hearing impaired, he or she will need to have confirmatory diagnostic evaluation. If a hearing disorder is detected, these investigations are required to provide as precise a characterization as possible, though usually it is enough if they show that the child has a permanent hearing loss of more than 35 decibels.
Therefore, the author concludes that well-run UNHS programs followed by observation yield positive results in terms of speech and general development in children with hearing impairments or disorders, with few risks or drawbacks. However, the author notes that data on the early detection of hearing impairment in newborns and infants are not very robust.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Stephanie Leveene