Hearing Assessment: Battery of Tests
A hearing test provides an evaluation of the sensitivity of a person’s sense of hearing and is most often performed by an audiologist using an audiometer. An audiometer is used to determine a person’s hearing sensitivity at different frequencies. There are other hearing tests like Tuning Fork Tests which the ENT surgeon does while doing other ENT examination.
We, at Decure International, have a dedicated audiology team for all the necessary tests required.
Prior to the hearing test itself, the ears of the client are usually examined with an otoscope to make sure they are free of wax, that the eardrum is intact, the ears are not infected, and the middle ear is free of fluid (indicating middle ear infection). The most common reasons to develop hearing loss due to genetic disorder, ageing problems, exposure to noise pollution, infections, birth complications, trauma to the ear, and certain medications or toxins.
Pure tone audiometry (PTA): First Step
The standard and most common type of hearing test is pure tone audiometry, which measures the air and bone conduction thresholds for each ear in a set of 8 standard frequencies from 250Hz to 8000Hz. The test is conducted in a sound booth using either a pair of foam inserts or supraural headphones connected to an external audiometer. The result of the test is an audiogram diagram which plots a person’s hearing sensitivity at the tested frequencies. On an audiogram an “x” plot represents the softest threshold heard at each specific frequency in the left ear, and an “o” plot represents the softest threshold heard at each specific frequency in the right ear. There is also a high frequency version of the test which tests frequencies over 8000Hz to 16000Hz which may be employed in special circumstances.
High Frequency Audiometry
High frequency audiometry (above 8 kHz) is performed using the same procedure as normal air conduction audiometry. High frequency audiometry is helpful when testing hearing impairments caused by ototoxicity, noise exposure, and acoustic traumas or in the assessment of patients with tinnitus. The frequency area is more susceptible to the effects of external factors such as medication and loud noises relative to the low and mid frequencies.
Impedance Audiometry /Tympanometry
This test tells us about the functioning of the middle ear and also that of the cochlea (i.e. inner ear). This is an objective test (i.e. the results are not dependent upon the subject’s response) and it helps the clinician to identify the nature of pathology in middle ear disorders, like whether it is a case of Otosclerosis, Otitis Media with Effusion, adhesive otitis media etc.
Whole Battery of Hearing Tests
- The audiologist or hearing instrument specialist may also conduct speech tests (Speech Audiometry), wherein the patient repeats the words he or she hears.
- The last test the audiologist may perform is an acoustic reflex In this test a probe is placed in the ear and a loud tone, greater than 70 dBSPL, is produced. The test measures the reflexive contraction of the stapedius muscle, which is important in protecting the ear from loud noises, such as a person’s own speech which may be 90 dBSPL at the eardrum. This test can be used to give information about the vestibular and facial nerves and indicate if a lesion may be present.