There are several different types of audiological tests used by audiologists to make an assessment regarding a child’s hearing and auditory function. An audiologist will usually use several of these tests to gain a complete picture of the child’s hearing ability and the functioning of the auditory system. While considering which types of tests to perform, an audiologist will have to take into account the child’s age and developmental level.
Conventional audiometry is one such test that is usually performed on children over the age of 5 and adults. By definition, it is a screening test used to assess hearing acuity by requiring a specific response to an acoustic stimulus. In other words, the subject’s hearing abilities are gauged by requiring them to perform a certain action on hearing a specific sound. The action required could be the pushing of a button or the raising of a hand. Assessment is done by the measurement of speech reception threshold (SRT) and word recognition measures. A comprehensive assessment will include tympanometry and testing for acoustic reflex and acoustic reflex delay.
The child is first seated in a sound-proof room and told to put on a set of headphones or earphones. The child is instructed to raise a hand or push a button each time a sound is heard. The hearing threshold is measured for different frequencies of sound. This is the faintest level at which a particular sound frequency is audible.
This method of hearing the sounds over headphones is known as air conduction method. Another method that may also be used to measure hearing threshold is bone conduction.
The various hearing thresholds are plotted on an audiogram. This graph shows the softest sounds that a person can hear at different frequencies. The hearing threshold for a particular sound frequency is determined by taking multiple readings at that frequency with a response detected at least 50% of the time. The threshold of hearing is compared to the normal threshold of 15 dB HL for the purpose of determining the degree of hearing loss.
The results of the test, taken together with the other audiometry tests deemed necessary by the audiologist, will define the nature and the degree of the hearing impairment. Once this is done, the audiologist can recommend the appropriate remedial action to be taken.
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