Complete hearing testing for ages four to adult provided by a certified clinical audiologist. Evaluations include measures of hearing sensitivity for air and bone conducted sounds and, when necessary, assessment of the middle ear function (impedance audiometry), and special testing to determine the location of dysfunction.
Hearing loss is not measured in percentages. The general hearing loss categories used by most hearing professionals are as follows:
- Normal hearing (0 to 25 dB HL)
- Mild hearing loss (26 to 40 dB HL)
- Moderate hearing loss (41 to 70 dB HL)
- Severe hearing loss (71 to 90 dB HL)
- Profound hearing loss (greater than 91 dB HL)
Brainstem auditory evoked potentials
ABR-Diagnostic Auditory Brainstem Response (ABR) is a diagnostic test which is similar to an elctroencephalogram (EEG). This procedure involves the use of clicking sounds to stimulate the auditory nerve, which produces an electical response. Electrodes placed on the patient's face and ears pick up the electrical activity of the nerve, and a computer displays the results for the audiologist to interpret.
Otoacoustic emissions testing (OAE)
Otoacoustic Emissions testing (OAE): measures the function of structures in the inner ear. The OAE are sounds (“echoes”) that are produced by the inner ear in response to sound stimulation. If the OAE is normal then we assume that structures in the inner ear are functioning normally.
The echo is found in most normal hearing individuals, so if echoes are present during OAE testing then the likelihood is that hearing is normal. If the echo is absent it could indicate that a hearing loss is present and referral for further testing such as Auditory Brainstem Response testing is made. OAE can be measured in newborn as well as older children. It is often used to get an estimate of inner ear function in children with developmental disabilities who cannot give behavioral responses.