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From Chapter 3, Universal Newborn Hearing Screening by Gilbert R. Herer, Ph.D.
Communicating through speech, hearing, and language is the single characteristic that most distinguishes human beings from the rest of the animal world.
When there is a problem with communication--such as hearing loss in infancy or early childhood--it can have profound impact on a child's social, emotional, and educational development, even his ultimate career goals...unless the problem is recognized, and intervention is begun, very early. Universal newborn hearing screening (UNHS) programs provide the essential first step to identification of hearing loss in infancy--a period when most, if not all, childhood hearing loss is present.
There are several reasons why it's vital to identify permanent hearing loss at birth or very soon thereafter. First, most sensorineural (SN) hearing losses are present at birth for well babies (1.2 per 1000); and during the neonatal period for babies hospitalized in newborn intensive care units (3.8 per 1000). That means these infants are already deaf or hard of hearing before parents bring them home from the hospital.
Second, even though a newborn infant doesn't speak, that doesn't mean he isn't hearing--and learning how to listen. An infant normally starts taking in information through his hearing, and begins to make basic associations between sound and meaning, from birth. In fact, the most important period of language and speech development occurs between birth and age two. During that time, auditory pathways in the brain are undergoing their rapid development--but if the brain doesn't receive stimulation from sound input during this vital period, those pathways will remain. So, clearly, the earlier an intervention plan is implemented, the better chance a child has of developing his hearing, speech, and language abilities to his maximum potential.
This chapter will review the history of newborn hearing screening: describe the protocol used by UNHS programs, including its follow-up procedures; report the outcome data for seven years from a very large screening program; and address vital issues concerning the needs of babies with hearing loss highlighted by the advent of UNHS programs.
The History of Universal Newborn Hearing Screening
Prior to 1993, the only recommended approach to identifying hearing loss in young children was through a Risk Factor Assessment. This approach had very limited effectiveness. It wasn't widely used--and when it was, it missed 50 percent of babies with hearing loss. The average age of identifying children with hearing loss in the United States, therefore, was eighteen to twenty-four months.
TABLE 1. Key Activities Supporting the Development of UNHS, 1993-2000
The National Institutes of Health (NIH) sponsor a multi-center research project on methods to identify neonatal hearing impairment.
The U.S. Department of Health & Human Services' Bureau of Maternal and Child Health initiates a five-year program of support to help seventeen states start UNHS programs.
Two major studies published in the journal Pediatrics demonstrate positive outcomes from early identification/intervention programs (Yoshinago-Itano, Sedey, Coulter & Mehl; Finitzo, Albright & O Neil).
The Federal Newborn Infant Hearing Screening and Intervention Act, sponsored by Rep. James Walsh (Rep., NY), is signed into law to provide funds to help states develop UNHS programs.
The Joint Committee on Infant Hearing issues guidelines for UNHS and follow-up services.
Positive outcome results from NIH's five-year multi-center research project are published in the journal Ear and Hearing (Norton, Gorga, Widen et al.).
The good news of the early 1990s was that two new methods for hearing screening became available--the evoked otoacoustic emissions (EOAE) and screening auditory brainstem response (SABR) procedures. Both are computerized, requiring no response from the child, so they are ideal for evaluating hearing loss in infants and toddlers. EOAE testing assesses the function of your child's cochlea--the spiral, fluid-filled structure of the inner ear, specifically, the function of the outer hair cells of the inner ear. SABR measures a change in the electrical activity of the auditory pathway from the cochlea to the brain in response to specific sounds. These two tests provided, for the first time, an opportunity for efficient and cost effective mass hearing screening of infants, and thus the earliest detection of and intervention for those with hearing loss. (See Chapter 2 for more on audiological assessments.)
A seminal research study from this period at the Women and Infants Hospital in Providence, Rhode Island, showed that, by using EOAE and SABR, newborns could be effectively screened for hearing loss. The report coincided with and influenced a 1993 National Institutes of Health (NIH) Consensus Conference on the early identification of hearing impairment in infants and young children. This conference recommended, for the first time ever, the development of universal newborn screening in the United States. This recommendation set in motion a number of key activities and events over the next seven years in support of universal screening in birthing hospitals throughout the U.S. (See Table 1.) Currently, thirty-eight states require all newborns to have their hearing screened before discharge. Interestingly, the average age of identifying hearing loss remained at eighteen to twenty-four months until the year 2001--because most state regulations were not enacted until 2000. Then, the change was dramatic. As of this writing (2006), the average age of identification (and thus access to intervention) is three to four months in states where UNHS is conducted.