There are numerous tests that can take place to measure how a client hears. In most cases more than one test will take place to carefully and accurately measure hearing.
Types of Tests
STANDARD HEARING TEST
A client will be asked to wear either headphones on or small earplugs in their ears and a small oscillator behind the ear. They will need to listen to sounds at different loudness levels and at different pitches. The client will respond each time they hear a sound by raising their hand or by pressing a button. The client will also likely be asked to repeat lists of words or sentences, at different loudness levels.
Part of a standard hearing test is to assess how well a person understands speech at levels that are loud enough for a person to hear well. This is called speech discrimination or word recognition. This information will tell the audiologist how well a person can expect to hear through a hearing aid.
AUDITORY BRAINSTEM RESPONSE TEST (ABR) OR BRAINSTEM EVOKED RESPONSE TEST (BAER)
This test measures the amount of time it takes for the sound to travel from your ear to auditory centers in your brain. The results of this test can be used to confirm hearing levels for individuals who may not be able to cooperate fully with standard testing, or to investigate if the auditory pathways between the ear and the brain are intact. It involves
having the client wear small soft earplugs in both ears and/or a small oscillator behind the ear. Four electrodes are then placed on their head. Sounds at different loudness levels and sometimes at several different pitches are presented into the ears while the electrodes measure the brain’s response to the sounds. A computer averages these responses and displays waveforms that are interpreted by the audiologist.
IMMITTANCE
A brief test that requires a small ear tip to be placed in the ear canal. One part of this test is Tympanometry which involves presenting air pressure into the ear canal to measure the movement of the eardrum. Sound is introduced into the ear canal at the same time as the air pressure. The reflection of the sound off of the eardrum is recorded. Various patterns indicate normal eardrum movement, negative or positive pressure present in the middle ear, or may be consistent with fluid in the middle ear. The second common part of this test involves testing your acoustic reflexes by presenting sounds into the ear to assess if the muscles in your middle ear tighten up when a loud sound is present. This test is not a hearing test; however, provides information about the functioning of parts of the outer and middle ear.
OTOACOUSTIC EMISSIONS TESTING (OAE)
This is a brief test that measures sounds created by vibrations of hair cells in the cochlea in response to sounds put in the ear by a small probe. OAE testing is very quick and is used both as a hearing screening tool and to obtain information about how part of the cochlea is working. OAEs give us the ability to document normal to near-normal functioning of the cochlea. The measurement is objective (that is, doesn’t require a response from the patient) and non-invasive.
It is important to know that the presence of OAEs rules out anything worse than a mild peripheral hearing loss, however the absence of OAEs does not necessarily mean that a hearing loss is present. More testing is required to make that determination.
