History
Prior to the advent of UNHS protocols, children with congenital deafness
were often not diagnosed until the absence of spoken language became of concern.
Deaf children were often 18 months of age or older at diagnosis. In 2000, JCIH endorsed the concept of UNHS through
an interdisciplinary system of early hearing detection and intervention.[2] UNHS
had become possible because of advances in technology that permit rapid
screening of infant hearing without employing highly trained
specialists.
In the years that followed, a significant expansion in UNHS programs
occurred. By 2005, every state had implemented a UNHS program and approximately
95% of newborns in the US were screened prior to hospital discharge using either
otoacoustic emissions (OAEs) or automated auditory brainstem evoked response
(ABR) technology.[1] In Illinois, UNHS became mandated by law in January of
2003. In calendar year 2007, 99% of live births in Illinois were screened
prior to hospital discharge (G. Tanner, AuD, administrator, Vision and Hearing
Section, IL Dept of Public Health, written communication, 2007).
UNHS programs have demonstrated both the feasibility and benefits of
early identification and remediation of childhood hearing loss. An expanding
body of literature demonstrates that intervention by 6 month of age for newborns
who are deaf or hard of hearing results in measurably higher performance in
vocabulary, articulation, speech intelligibility, social adjustment and
behavior, which are important in school functioning.[3]
Earlier diagnosis and intervention
To minimize treatment delays, the updated JCIH guidelines urge hearing
screening by recommended technologies (OAEs or automated ABR) by 1 month of age
at the very latest. In addition, infants failing initial screening and a
subsequent rescreening should complete the diagnostic testing necessary to
confirm loss by 3 months of age. To achieve the latter recommendation, infants
with otitis media with effusion would in most cases need to have this issue
resolved in order for accurate threshold testing to be accomplished. In the
event of permanent hearing loss in which amplification would be appropriate and
beneficial, fitting of hearing aids is recommended within 1 month of
diagnosis.
Expertise in infant hearing loss needed
To improve diagnostic accuracy and outcome of intervention, the updated
guidelines specify that audiologists with skills and expertise in evaluating
newborns and young infants provide the diagnostic evaluations and fitting of
amplification. Similarly, the otolaryngologists who evaluate infants with
confirmed hearing loss should be knowledgeable in the area of early childhood
hearing loss. Expertise in evaluating infants also is suggested regarding
ophthalmologic consultants called upon to assess visual acuity. Also of great
importance is the recommendation that early intervention providers involved with
these children have expertise in infant hearing loss. The latter is particularly
important as many parents and medical professionals are unaware that it is
uncommon for speech pathologists, teachers and audiologists to have extensive
experience in managing hearing impaired infants and toddlers, unless they have a
special interest, completed additional training and/or practice in a setting
focused on hearing impaired children in this age group.
Auditory neuropathy merits special consideration
The new JCIH guidelines acknowledge the need for special procedures to
identify children with auditory neuropathy/dys-synchrony (AN). This is a
disorder in which there is poor synchrony in the firing of the hearing nerve in
response to sound. Children with AN are at significant risk to develop very poor
communication skills.[4,5] These children often pass hearing screening using
OAEs, the most commonly employed technology in UNHS programs. In contrast,
infants with AN are likely to be referred for further evaluation if screened via
automated ABR, as this test relies on the presence of neural synchrony in
response to sound.[5]
As children with a history of a neonatal intensive care unit (NICU ) stay
are more likely to have AN, the new guidelines recommend that all NICU infants
admitted for more than 5 days have ABR screening, not OAEs alone, as an integral
part of their hearing screening protocol.[6-8]
It is of special importance that children with AN undergo diagnostic ABR
testing conducted by an experienced pediatric audiologist. The necessary testing
to diagnose AN requires specialized protocols to distinguish AN from more common
sensorineural hearing loss. Recognizing which problem is present is critical as
initial treatment and counseling are quite different. Children with AN often do
not benefit from amplification, yet often do benefit from cochlear implantation.
A small number experience spontaneous resolution of AN during infancy. Thus,
their clinical presentation is highly variable. They often initially exhibit the
ability to detect sounds, yet do not typically develop the ability to adequately
understand spoken language or to acquire speech that is age appropriate.
Audiologists and otolaryngologists who specialize in early childhood hearing
loss are more likely to have the clinical experience necessary to counsel
parents of these children.
Onset of sensorineural hearing loss after passing UNHS
Implementation of UNHS has resulted in increased awareness that children
develop sensorineural hearing loss after birth more often that previously
recognized. Therefore, the updated guidelines recommend that hearing be
reevaluated in children with known risk factors for progressive hearing loss,
with earlier and more frequent reevaluations in children with higher likelihood
of delayed onset hearing loss (see Table 1). However, a minimum of 1 diagnostic
assessment by age 24 to 30 months is suggested.[9]
A significant number of children without known risk factors at birth also
develop sensorineural hearing loss after birth. This group of children includes
those with mutations of the Connexin 26 gene, the most common genetic cause of
non-syndromic bilateral childhood sensorineural hearing loss. As this condition
is autosomal recessive, the family history is often negative. Thus these
children typically present without evidence of risk factors until the etiology
is proven via molecular genetic testing. Of the 51 children in the author's
practice diagnosed with mutations of Connexin 26, 27% have had a history of
having passed UNHS.[10]
To address the issue of progressive loss in children without obvious risk
factors, the JCIH recommends continued regular surveillance of developmental
milestones including auditory and spoken language skills beginning at 2 months
of age as suggested by the AAP.[11] Global screening by an objective validated
assessment tool that includes speech and language is suggested at 9, 18, 24 and
30 months of age, or at any time the primary care physician or family has
concerns. Infants and children who do not pass the speech/language portion of
the global screening or for whom there is concern regarding hearing or language
should be referred for both speech/language and audiology
evaluations.
Impact on childhood deafness
The success of UNHS has enabled growing numbers of children to take
advantage of newer diagnostic and intervention technologies, including improved
hearing aids, assistive devices and cochlear implants. Identifying children with
bilateral profound sensorineural hearing loss has the potential to significantly
improve their lives, assuming that early identification leads to early referral
for cochlear implant candidacy evaluation.
Prior to implantation, on average, deaf children developed language at
half the rate of normal hearing children.[12] Most deaf children were educated
in self-contained classrooms where sign language was the primary mode of
communication. On average, fourth-grade literacy has been achieved by deaf
children in these programs. Few developed intelligible spoken language. The
result was a significantly lower rate of high school graduation and enrollment
in postgraduate education, as well as a significantly lower rate of full
employment and earnings.[12]
Improved hearing through a cochlear implant has been shown to double the
language growth rate for children in both sign language and oral education
programs.[13] In addition, cochlear implantation positively impacts the ability
of these children to understand spoken language and provides the opportunity for
many to learn to talk.
Improved outcomes from implantation are more likely if the period of
auditory deprivation is abbreviated. Therefore, identifying deaf children early
in life for whom hearing aids are not enough is critical to enable these
children to achieve their full potential.
References
[1.] Joint Committee on Infant Hearing. Year 2007 Position Statement:
Principles and guidelines for early hearing detection and intervention programs.
Pediatrics 2007;120:898-921.
[2.] Joint Committee on Infant Hearing; American Academy of Audiology,
American Academy of Pediatrics, American Speech-Language-Hearing Association,
Directors of Speech and Hearing Programs in State Health and Welfare Agencies.
Year 2000 Position Statement: Principles and guidelines for early hearing
detection and intervention programs. Pediatrics 2000;106:798-817.
[3.] Yoshinaga-Itano C. Levels of evidence: Universal newborn hearing
screening (UNHS) and early hearing detection and intervention systems (EHDI). J
Commun Disord 2004;37:451-465.
[4.] Sininger YS, Hood IJ, Starr A, et al. Hearing loss due to auditory
neuropathy. Audiol Today 1995;7:10-13.
[5.] Sininger YS, Abdala C, Cone-Wesson B. Auditory threshold sensitivity
of the human neonate as measured by the auditory brainstem response. Hearing Res
1997;104:27-38.
[6.] Berg AL, Spitzer JB, Towers HM, et al. Newborn hearing screening in
the NICU: Profile of failed auditory brainstem response/passed otoacoustic
emission. Pediatrics 2005;116:933-938. Published correction appears in
Pediatrics 2006;117:997.
[7.] Shapiro SM. Bilirubin toxicity in the developing nervous system.
Pediatr Neurol 2003;29:410-421.
[8.] Starr A, Picton TW, Sininger Y, et al. Auditory Neuropathy. Brain
1996;119:741-753.
[9.] Johnson JL, White KR, Widen JE, et al. A multicenter evaluation of
how many infants with permanent hearing loss pass a two-stage otoacoustic
emissions/automated auditory brainstem response newborn hearing screening
protocol. Pediatrics 2005;116:663-672.
[10.] Young NM, Meyer AK, Hoff S. Identification of GJB2 mutations in a
large urban pediatric population. Poster Presentation COSM, 2008.
[11.] American Academy of Pediatrics, Committee on
Practice and Ambulatory Medicine. Recommendations for preventive pediatric
health care. Pediatrics 2000;105:645-646.
[12.] Mohr PE, Feldman J, Dunbar J. The societal cost of severe to
profound hearing impairment in the United States. Project HOPE.
International Journal of Technology Assessment in Health Care
2000;16(4):1120-1135.
[13.] Robbins AM, Svirsky M, Kirk KI. Children with implants can speak,
but can they communicate? Otolaryngol Head Neck Surg
1997;117:155-160. | 
