Special Advice: Do you suspect a hearing problem?

In the second part of a series on hearing impairment, we look at screening procedures for different ages


So you have realised your child doesn't hear as well as he should and you suspect a hearing impairment - now what?

Hearing screening tests provide a quick and cost effective way to separate people into two groups: a pass group and a fail group. Those who pass hearing screening are presumed to have no hearing loss. Those who fail are in need of an in-depth evaluation by an audiologist and may also need follow-up care from other professionals. Hearing screening can be provided from birth throughout the adult years when requested.

Hearing and balance can be assessed by an audiologist, and disorders treated and rehabilitated. An audiologist's job is to select, fit, and dispense amplification systems such as hearing aids. They prevent hearing loss by providing and fitting protective devices and can be consulted on the effects of noise on hearing and consumer education. It is recommended that all hearing screening programmes be conducted under the supervision of an audiologist holding the American Speech-Language-Hearing Association's (ASHA) Certificate of Clinical Competence (CCC).

SCREENING PROCEDURE FOR DIFFERENT AGE GROUPS

Newborns and Infants: Hearing screening for newborns before they leave the hospital or maternity centre is becoming a common practice. Screening procedures for newborns and infants can involve use of non-invasive, objective physiologic measures that include oto-acoustic emissions (OAEs) and/or auditory brainstem response (ABR). Both procedures can be done painlessly while the infant is resting quietly.

Without such programmes, the average age of hearing loss identification will stay at 12 to 25 months. When hearing loss is detected late, language development is already delayed. Children who are identified early and receive early intervention are found to function at the level of their peers by the time they enter school.

Infants who do not pass a screening are often given a second screening to confirm findings and then referred for follow-up audiological and medical evaluations that should occur no later than three months of age. If an infant passes the screening but has any risk factors for progressive or delayed-onset hearing loss (as mentioned in the box), he should receive audiological monitoring every six months until the age of three years.

Older Infants and Toddlers: Infants and toddlers, seven months to two years, should be screened for hearing loss as needed, requested, mandated, or when conditions place them at risk for hearing disability.

Infants, older infants and toddlers who received neonatal intensive care or special care, or who display other indicators that place them at risk for hearing loss should also be screened.

This screening should be done even if an initial hearing screening is passed because some causes of hearing loss do not take effect until later in the child's development. These children' s hearing should be monitored at least every six months until three years of age, and at regular intervals thereafter, dependent upon the risk factor.

Two screening methods are suggested as the most appropriate tools for children who are functioning at a developmental age of seven months to three years - visual reinforcement audiometry (VRA) and conditioned play audiometry (CPA). Both of these methods are behavioural techniques that require involvement and cooperation of the child.

With both of these methods, sounds of different frequencies are presented at a sound level that children with normal hearing can hear. It is ideal if the child will allow earphones to be placed on his or her head so that independent information can be obtained for each ear. If this is not possible then sounds are presented through speakers inside a sound booth.

Since sound field screening does not give ear specific information, a unilateral hearing loss (hearing loss in only one ear) may be missed. Alternative procedures, oto-acoustic emissions (OAEs) or auditory brainstem response (ABR) may be used if the child is unable to be conditioned or is uncooperative.

A toddler who does not pass the screening should be re-screened or referred for audiologic evaluation.

Pre-schoolers: The goal of screening for hearing loss in pre-schoolers, ages three to five years, is to identify children most likely to have hearing loss that may interfere with communication, development, health, or future school performance. In addition, because hearing loss in this age range is so often associated with middle ear disease, it is also recommended that children in this age group be screened for outer and middle ear disorders.
If the child cannot be conditioned to the play audiometry, the child will be screened using infant-toddler procedures or will be recommended for a more in-depth audiological assessment. If the child did condition and did not pass the screening, then referral for audiological assessment by an ASHA-certified audiologist will be made.

School age (five to 18 years): School-age children should be screened for hearing loss as needed, requested, mandated, or when conditions place them at risk for hearing disability. School age children with even minimal hearing loss are at risk for academic and communication difficulties. Periodic screenings are recommended if there is an exposure to high levels of noise so that any hearing impairment may not affect their future educational, vocational, or social opportunities. School age children should be screened at the following times:

* On first entry into school.

* Every year from kindergarten to third grade.

* In the seventh grade.

* In the 11th grade.

* Upon entrance into special education.

* Upon grade repetition .

* Upon entering a new school system without evidence of having passed a previous hearing screening.

School age children who already receive regular audiological management need not participate in a screening programme.

HEARING SCREENING SHOULD BE DONE IN OTHER YEARS WHEN:

* Parent/care provider, healthcare provider, teacher, or other school personnel have concerns regarding hearing, speech, language, or learning abilities.

* There is family history of late or delayed onset hereditary hearing loss.

* Otitis media with effusion (fluid in the middle ear) recurs or persists for at least three months.

* There are skull or facial abnormalities, especially those that can cause changes to the structure of the pinna and ear canal.

* Characteristics or other findings occur that are associated with a syndrome known to include hearing loss.

* Head trauma occurs with loss of consciousness.

* There is reported exposure to potentially damaging noise levels or to drugs that frequently cause hearing loss.

Adults: Hearing loss is a prevalent chronic condition among adults of all ages. It is recognised that hearing loss increases as a function of age. However, adults tend to ignore its effects, delay their decision to seek audiologic services and ten