There are typically two parts of a hearing evaluation. Pure tone thresholds (air/bone) and speech audiometry. The basic hearing exam has remained unchanged for the past 50 years.
Audiology as a profession got its start after World War II. Many returning veterans had hearing loss from the explosions and gunfire associated with combat. Dr. Raymond Carhart of Northwestern University was the first professor to start an audiology program. What all professions need are standards. Dr. Carhart and his associates are credited with establishing many of the current standards of a traditional hearing exams.
First, standards for normal hearing were established. One thousand normal (self-reported) 18 to 20 years were tested using pure tones (air/bone) from 125-8000 Hz. The average of these subjects became our “normal hearing” thresholds. That is why the range of normal hearing is 0-20 dB or 0-25 dB (depending on who you consult).
The next part of a hearing test is speech audiometry. This test is designed to evaluate a patient’s ability to recognize or detect speech. Similar to the pure tone exam, speech exam are standardized based on results of mass samples. There two main speech exams. Spondee Recognition Threshold (SRT) and Word Recognition Scores (WRS). Spondee words are two syllable words with equal emphasis on both syllables. Words such as baseball, hotdog, airplane, etc. These words are purposefully redundant to make it easy for the patient to correctly understand the word. Word recognition testing are one syllable words with no redundancy.
There are innumerable variations of list that can be used, however all have been standardized to ensure good test-re-test reliability.
Other speech exams include Speech in Noise (SIN Test). Speech in Noise exams evaluate a person’s ability to recognize speech in the presence of differing levels of background noise. Speech in noise test can help in deciding what type of hearing aid a patient may need.
These are the basic parts to every hearing evaluation. Most states require that both pure tone (air/bone) and speech audiometry be performed on every patient before they can be fit with a hearing aid. Nevada is one of those states. So if you are not receiving both exams ask your provider why.