Hearing evaluations are completed in a soundproof booth (a room with special treatment to the walls, ceiling, and floor to ensure that background noise does not affect test results).  The hearing evaluation allows an audiologist to determine whether a patient has a hearing loss and, when they do, to establish the type, degree (severity) and configuration of the loss.   The following tests are performed during a hearing evaluation:
 

Pure-Tone Audiometry

The audiologist introduces sounds into the soundproof booth through earphones, speakers, and/or a special bone transducer ("vibrator") that is placed just behind the ear or on the forehead. Hearing thresholds, or the faintest tones a person can hear, are determined at selected pitches (frequencies) from low to high.

Where as sounds presented via earphones or speakers travel through the entire hearing system (outter, middle and inner ear), sounds presented via the bone transducer by-pass the outer and middle ear and directly stimulate the inner ear. By comparing results obtained from earphones to those from the bone transducer, the audiologist is able to determine whether an identified hearing loss is sensorineural ("nerve type hearing loss") or conductive (outer or middle ear pathology).  

The results of a pure-tone test are plotted on an audiogram. The audiogram is a chart that graphically represents a patients hearing sensitivity; frequency (pitch) is plotted on the x-axis (the horizontal axis) and intensity (loudness) is represented on the y-axis. 

• Red circles (o) indicate the results obtained from the right ear under earphones and blue x's (x) indicate the results obtained from the left ear under headphones. 
• The '< ' and '[' symbols represent right ear 'bone' results and the '>' and ']' symbols represent left ear 'bone' results. 
   

                                

 

Speech Audiometry

A speech reception threshold (SRT) and word recognition score are also determined.

• A Speech reception threshold represents the faintest level at which a person can hear and correctly repeat easy-to-distinguish two-syllable (spondaic) words; one is determined for each ear. 
• Tests of word recognition evaluate how well a person can distinguish words at a comfortable listening level; the individual is aksed to repeat words (or point to pictures) and the percentage of words correctly identified is recorded for each ear.  

Acoustic Immittance

Immittance testing is performed to determine the status of the tympanic membrane (ear drumb) and middle ear via tympanometry, as well as to evaluate acoustic reflex pathways, which include cranial nerves (CN) VII and VIII and the auditory brainstem.

• Tympanometry measures sound reflection from the tympanic membrane while the operator varies air pressure in the ear canal. Tympanometry aids assessment of the outer and middle ear system, including the Eustachian tube.
• Acoustic Reflex Threshold is a middle ear measurement of stapedius muscle response to higher intensity sounds, as measured at distinct fequencies (pitches).