Testing must be performed only by licensed physicians or licensed audiologists.
Bone conduction equipment needs to be properly calibrated.
Testing must include the following.
- Tympanometry. If tympanometry is abnormal, medical referral is indicated prior to further testing.
- Perform otoacoustic emissions. If abnormal, proceed to ABR.
- Perform ascending click-evoked threshold search and 4000 Hz-toneburst ascending threshold search via air conduction. (Normal sensitivity for clicks may be defined as a repeatable wave V threshold of 30 dB nHL.)
- If either the click ABR or the 4000 Hz toneburst ABR is abnormal, perform ascending threshold search toneburst ABR at 2000Hz and 500Hz.
- If air conduction click thresholds are abnormal, perform ascending threshold search via bone conduction. Air-bone gaps of 20 dB or more should be considered significant.
- If time permits, perform click-evoked, neurodiagnostic ABR via air conduction.
- Test at 70-80 dB nHL, to evaluate retrocochlear function.
- Evaluate absolute latencies for waves I, III and V.
- Evaluate interpeak latencies for waves I to III, III to V, and I to V.
- Evaluate waveform morphology.
- Prepare a written report interpreting test results and describing the diagnostic profile.
- If hearing loss is confirmed, provide the parents with the Oregon Health Services list of early intervention educational institutions.
- Disseminate written report and other information to the infant's primary care provider and other care providers and agencies as requested by the parents.
- If test results are inconclusive, further audiological evaluation using appropriate behavioral techniques is warranted, prior to six (6) months of age.