Pure tone audiometry and masking are tests done to measure the hearing threshold of an individual. The instrument used to conduct these tests is known as audiometer. In pure tone audiometry and masking tests the peripheral and central auditory systems are measured. The audiometer is used as an instrument for measuring the acuity of hearing, and threshold of audibility. There are two types of audiometers which are widely used across the world one that requires a subjective response from the patient while the other does not.
There are different levels of hearing loss. Normal hearing loss is anything in the limits of 0-24 DB while mild hearing loss is 26-40DB, moderate hearing loss is 41-55 DB moderate – severe hearing loss is 56-70 db severe hearing loss is 71-90 db and profound hearing loss is anything above 90 db. While doing a pure tone audiometry and masking test there are different apparatus used such as Oscillator, Interrupter switch, Hearing level attenuator, Equalization circuit, and Output power amplifier. The method of pure tone audiometry and masking is used in order to separate the test ear and make sure that results found are the true benchmarks of the test ear. When pure tone masking audiometry and masking audiology is done the person is made to hear a continuous noise in the ear that is not been tested so as to prevent crossover from the ear that is being tested. With the help of masking you can find out if there is loss of hearing only in one of both also whether it is partial or complete. Thus when conducting the ear which is being tested has to detect the signals or sound and the person has to respond accordingly. This signal reduction is known as interaural attenuation. For masking conventional headphones are used.
The main goal of pure tone masking is having the same frequency as the audiometer tone is that there will be grave difficulty in distinguishing the two sounds. Pure tone audiometry and masking hearing aid can be used for those who have permanent hearing loss. There different types of audiology test conducted that are air condition, bone condition, crossover and masking. In air condition assess the sensitivity when the signal travels through the outer middle inner and then through the brain to the cortex. In bone condition the signal is passed through the bones of the skull and then the cochlea and then through the audio way of the brain to check for the sensitivity.