Degrees of Hearing Impairment
For Children

Frequencies in Hz

Normal Hearing

Children with thresholds less than 15 dB HL have normal hearing. These children will be able to hear vowels and consonants. Speech sounds will be heard clearly and consistently. Children with normal hearing are able to understand rapid speech better than a child with even a mild hearing loss. These children are better equipped to understand speech when background noise is present.

Mild Hearing Loss

Children with thresholds 15 dB HL – 30 dB HL have a mild hearing loss. Speech sounds are not heard clearly and consistently. These children will be able to hear the vowel sounds, a, e, i, o, u, clearly, but they may miss some consonants. For example, they may miss the sounds p, h, f, s and th. A mild hearing loss will make it difficult for a child to understand speech, when background noise is present. Rapid speech also poses a problem.

Moderate Hearing Loss

Children with thresholds 30 dB HL – 50 dB HL have a moderate hearing loss. Without the amplification of hearing aids and implementation of auditory training and speech therapy, these children will miss most sounds at a normal conversation level. Due to inaccurately hearing sounds and missing sounds completely, children with a moderate hearing loss may have a limited vocabulary and difficulty with grammatical rules, word placement in a sentence and word meanings.

Severe Hearing Loss

Children with thresholds 50 dB HL – 70 dB HL have a severe hearing loss. No sounds can be heard at normal conversation level, without amplification by a hearing aid. If a severe loss is not detected at birth, or shortly there after, language and speech will not develop spontaneously and learning dysfunction is possible. If a severe hearing loss is identified early, and the child is fit with hearing aids and auditory training and speech therapy are implemented, the child has a much more positive outlook on speech and language development and facility of learning.

Profound Hearing Loss

Children with thresholds greater than 70 dB HL have a profound hearing impairment. Without the use of hearing aids, these children, generally, are unable to hear sound. Children with a profound hearing loss will experience severely impeded language development and learning dysfunction. The speech of these children is characterized by extended vowel sounds, distortion of vowel sounds, slow speech, excessive nasality and abnormal rhythm. Children with a profound hearing loss are able to learn speech and language with the use of hearing aids and intensive training and education.

Children with mild, moderate, severe and profound hearing losses can all benefit from the use of hearing aids, auditory training and speech therapy. The type of hearing aid and intensity of auditory training and speech therapy can be determined by an Audiologist and Speech Language Pathologist, based on each child’s hearing loss and special needs.

A Trip to the Audiologist

Here are a few things that can be expected at a visit with an Audiologist. First, the Audiologist will request information about the child including medical history and overall development, speech and language development and the parents’ observations and concerns regarding the child’s hearing.

If the child is between birth and two years of age, the Audiologist will begin testing with Behavioral Observation Audiometry (BOA). With BOA, the Audiologist observes the child’s unconditioned responses, such as head and/or eye movement, in response to sounds produced by noisemakers and soundfield signals, in a controlled environment.

Testing usually begins in the soundbooth for children two and older, where several tests are performed in order to obtain an accurate measure of the child’s hearing thresholds at different frequencies. The following are tests the could be performed:

1. Speech Reception Threshold (SRT) – The audiologist tries to find the softest test sound level at which the child is able to identify 50% of spoken words.

2. Audiometry - The child wears a set of earphones and is asked to respond, when he or she detects a sound generated by an audiometer. The audiologist will test different frequencies.

3. Bone Conduction – A bone conduction receiver is placed behind the ear, and the child is asked to respond when he or she detects a sound produced by the device. The Audiologist will test different frequencies.

The Audiologist will examine the ear canal and tympanic membrane (ear drum), with an otoscope, before continuing with immittance testing. The immittance test battery includes the following tests:

1. Tympanometry – This test measures how easily sound flows through the tympanic membrane (ear drum), while air pressure is varied against it.

2. Acoustic Reflex Measurement – This test measures the contraction of the middle ear muscles in response to loud sounds.
   
   
3. Physical Volume Measure

For children who are physically or mentally incapable of cooperating to perform the conventional audiometric tests, which require participation, there are other tests, which measure the hearing function of a child without his or her active participation.

After reviewing the patient’s information and test results, the Audiologist will be able to describe a hearing loss as unilateral (affecting one ear) or bilateral (affecting both ears), the degree of hearing impairment: mild, moderate, severe or profound, and the type of loss: conductive, sensorineural or mixed. If he or she deems necessary, the Audiologist will make referrals to other professionals. He or she will make recommendations regarding amplification and provide suggestions on how to best manage the hearing impairment.

Contributed by Brandi Pandis