Adapted and reprinted with permission from American Speech-Language-Hearing Association's "Lets Talk."

A diagnostic audiological evaluation is sometimes thought of as “just a hearing test.” But more than “just” the ability to hear sounds is involved. The basic audiological evaluation consists of several different components: a case history, physical examination, pure tone test, speech audiometric tests, and acoustic immittance audiometry. Additional special testing may be required, depending on the initial test results.

The audiologist asks several questions during the case history such as, “How long have you noticed difficulty with your hearing? Was this a gradual or a sudden onset? Do you have ringing in your ears? Is there a history of ear infections? Have you noticed any pain or discharge from your ears? Is there a family history of hearing loss? Do you have greater difficulty hearing women’s, men’s or children’s voices?” For children, questions will be asked regarding speech and language development, recognition of and response to familiar sounds (a telephone ringing, a knock at the door, or music), and if the child startles in response to loud sounds such as a dog barking, ballon popping, or a door slamming. The answers to these and other questions, as well as any volunteered information, will assist in obtaining useful background data.

A video otoscope Ð an instrument that contains a light and magnifies the ear onto a TV screen Ð is used during the physical examination. The ear is examined for the presence of excessive cerumen (wax), foreign objects (toys, food, pieces of cotton swabs, etc.), holes in the eardrum, signs of infection, or any other indications of the need for a referral for a medical evaluation.

The pure tone test is completed in a soundproof booth, a room with special sound treating to the walls, ceiling and floor to ensure that background noise does not affect the test results. Only those sounds that the audiologist introduces into the room (either through earphones or through speakers located in the room) will be heard. Sounds may also be sent through a special headset that has been placed just behind the ear or on the forehead. The patient is instructed to give some type of response, such as raising a finger or hand, pressing a button, pointing to the ear where the sound was received, or saying ‘yes’ to indicate that the sound was heard. Sometimes children are given a more play-like activity to indicate response. They may be instructed to string a peg, drop a block in a bucket or place a ring on a stick in response to hearing the sounds. Infants and toddlers are observed for changes in their behavior in response to sounds, such as sucking a pacifier, quieting or searching for the sound.

The audiologist uses an audiometer to present tones at different frequencies (pitches) and intensity levels. The frequency or pitch of the sound is referred to in Hertz (Hz). The intensity of the sound is measured in decibels (dB). Responses are recorded on a chart called an audiogram. In certain situation, other types of sounds (such as white noise, environmental sounds, music or noisemakers may be used.)

Speech audiometry includes speech recognition threshold (SRT) and word recognition (discrimination) scores. The SRT estimates the lowest level at which speech is identified correctly at least half the time. Two-syllable words are used, such as baseball, playground, sidewalk and airplane. The results are expressed in dB.

Word recognition tests attempt to evaluate how well you understand what you have heard. Singe-syllable words, such as chew, what and knees are spoken at a comfortable loudness level. Words may be presented in quiet and then in the presence of background noise. People who have difficulty speaking or those who are unable or unwilling to speak may respond by pointing to pictures or objects. A numerical score is obtained based on responses. A score of 0% indicates no understanding of the speech signal. A score of 100% indicates every word was identified correctly.

Acoustic immittance measurement are valuable in evaluating the outer and middle ear. The testing can assist in the detection of an ear infection, holes in the eardrum, wax blocking the ear canal, or other problems that indicate the need for a medical evaluation. Tympanometry, one aspect of immittance testing, gently introduces air pressure into the ear canal. Sounds similar to those heard during the pure tone test are used; however, the patient need not respond. The audiologist may also measure the acoustic reflex, a contraction of muscles in the middle ear in response to loud sounds Ð a reaction that serves to protect the ear from potentially damaging noise levels. The level of response or the absence of the acoustic reflex offers additional diagnostic information.

The audiologist will review each component of the audiological evaluation to obtain a profile of hearing abilities and needs. Additional special testing may be indicated based on the initial test results. As you can see, a diagnostic audiological evaluation is more that “just a hearing test!”

Contact your local audiologist for more information on diagnostic hearing evaluations for infants, children and adults, the effects of noise on hearing, how frequent ear infections affect hearing ability, and many other topics of concern regarding your hearing health and hearing health are.

This article brought to you by:

Peninsula Hearing Services

Karen M. Martin, Au.D.

105 Shady Lane, Soldotna 99669

(907) 262-3224