Hearing tests can be classified into two main types: diagnostic and screening. Screening tests that employ pure tone audiometry via basic air conduction are utilized to rapidly assess whether more comprehensive diagnostics tests are necessary.
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Otoscopy is the first step in any screening. By visualizing the ear canal and eardrum, the screener can examine for wax occlusion, foreign objects, and ear infections. The subject is ready for air conduction testing after otoscopy.
Air conduction
Air conduction exams assess the entire hearing system simultaneously. Headphones are placed on or over the ears (or earphones are inserted into the ear canal) so that the person being examined can hear the sounds.
The sound waves enter the outer ear canal, travel into the middle ear space, and enter the inner ear organ, or cochlea. Here, the sound waves are converted into an electrical signal that the brain can comprehend.
Following the presentation of a sound, the patient is expected to respond. Typically, the examiner will ask the patient to raise their hand or press a button.
Newborn hearing screening
Newborn hearing screening is an important procedure designed to identify hearing impairments in infants shortly after birth. Early identification and intervention for hearing loss are essential, as hearing plays an important role in a child's language development and overall communication abilities.
This screening is usually performed within the first few days of a baby's life, preferably before they leave the hospital or birthing center. There are two primary methods for newborn hearing screening:
Otoacoustic emissions screening
Otoacoustic Emissions screening (OAEs) assesses the function of the cochlea by examining the outer hair cell function. A probe microphone is inserted into the ear canal. It plays sounds and the response by the hair cells echo is recorded.
These screenings are commonly employed for newborn hearing screenings or for young children who cannot participate in air conduction testing.
OAE screening test results are pass or fail. A failed result does not necessarily indicate that hearing loss is present, but it should always prompt a re-test or a referral for more comprehensive testing.
Auditory brainstem response screening
Auditory Brainstem Response (ABR) screening tests examine how the auditory nerve responds to a sound stimulus. For newborn hearing screening, the infant wears electrodes that are attached to their head, and muff-style headphones are placed on their ears.
When the sound is presented in the test, a neural response is recorded. Similar to the OAE, the screenings provide a pass/fail result. ABR is the favored newborn hearing screening test because it examines the auditory nerve, whereas an OAE only examines the cochlea.
Mild hearing loss can impair a child’s speech and language development. It is therefore crucial that screening for hearing continues throughout childhood.
Hearing screenings for adults are also very important, as emerging research highlights the significance of hearing and brain health. Early detection of hearing loss results in timely treatment.
Child hearing screening
Air conduction screening tests for children typically commence as early as four years old and are commonly conducted in pediatrician’s offices, schools, and occasionally at the child’s home.
These tests can be conducted by trained nurses, teachers, speech pathologists, volunteers, and sometimes by audiologists, and are usually categorized as a pass or fail.
A headset that fits over the child’s ear is utilized to present the tones. A standard intensity, often chosen for children, such as 20 dB is applied. 4 frequencies are tested, typically 500, 1000, 2000, and 4000 Hz.
If a child does not respond to one or more of these frequencies, they will be referred to an audiologist for more comprehensive testing. Creating a quiet space with minimal distractions is a crucial factor for accurate screening: a child may fail if the test environment is too noisy or if they become distracted.
Screening exams are significant for children as they can serve as the initial indicator of hearing loss, ear infections, or other ear disorders.
Adult hearing screening
Adult screening test protocols differ based on the purpose of the screening. Exams are conducted by various individuals and in diverse settings, such as doctor’s offices, assisted living facilities, workplaces, and even at a patient’s home.
One of the most common reasons for adult screening is occupational noise. In many countries, employees in a workplace that has noise environments of 85 dB for over eight hours must have routine screening tests.
Testing for occupational noise involves threshold testing, where the patient must respond to the softest sound that they can hear.
Typically, frequencies of 500, 1000, 2000, 3000, 4000, and 6000 Hz are assessed. In this type of screening the tester is looking for hearing loss (threshold responses of 30 dB or more) and threshold shifts (changes in hearing response of 15 dB or more).
The hearing screenings for adults are like those discussed for children, as a pass-or-fail test. These screenings help determine whether a patient should be referred to an audiologist for a diagnostic test and hearing consultation.
Screening audiometers
Amplivox’s comprehensive range of reliable, accurate, and PC-based screening audiometers offers a perfect solution for newborn, child, and adult hearing screening.
All Amplivox’s devices are portable and user-friendly, delivering a customized and flexible mobile or static solution. Alongside providing hearing screening and data management tailored to the user’s specific demands, Amplivox also ensures efficient and accurate testing.
References and further reading
American Speech-Language Hearing Association. Hearing Screening. Accessed at: https://www.asha.org/public/hearing/hearing-screening/
Centers for Disease Control Prevention (2018). Noise & Hearing Loss Prevention: Hearing Loss Prevention Programs. Accessed at: https://www.cdc.gov/niosh/programs/ppops/hlp.html
Centers for Disease Control Prevention (2022). Screening and Diagnosis of Hearing Loss. Accessed at: https://www.cdc.gov/ncbddd/hearingloss/screening.html
American Speech-Language Hearing Association. Adult Hearing Screening. Accessed at: https://www.asha.org/practice-portal/professional-issues/adult-hearing-screening/
American Speech-Language Hearing Association. Types of Tests Used to Evaluate Hearing in Children and Adults. Accessed at: https://www.asha.org/public/hearing/types-of-tests-used-to-evaluate-hearing/
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