A hearing test is the most important way to properly measure and determine a patient’s degree of hearing loss. When conducted properly, a thorough hearing test provides detailed information about the level of hearing in each ear and helps clarify the type of hearing loss as well.
There are many steps that might occur during a hearing test. The most common step is a ‘tone test’. During a tone test, each ear is tested to see how much volume is required to detect each of 8 to 10 tones. Some of the tones are very deep toned (low frequency), and some of the tones are very shrill or high toned (high frequency), and some of the tones are in between, or mid-toned. The tone test measures how much volume is required to just barely detect each tone. The lower the volume necessary to just hear the tone, the better the patient’s hearing is for that tone.
Think of the tone test like tapping individual key on a piano keyboard. During the tone test, we tap 8-10 keys on the keyboard, from the deepest notes at the far left to the highest notes at the far right. Normal hearing means you can hear the note when a specific key on the keyboard is barely tapped. The harder the key has to be tapped for you to barely hear the note, the more hearing loss you have at that note.
When hearing loss is deep enough for some notes, you will not hear it regardless of how loud it is played. So imagine sitting at the piano. You gently tap a key on the keyboard at the far left, and you hear a faint deep note. Then you gently tap a key in the middle of the keyboard . . . and hear nothing. So you tap a little harder . . . still nothing. And then when you tap even harder, you finally hear a faint middle tone. When you use that same amount of pressure to tap the key at the far left of the key board, the deep note is very loud. This indicates a significant hearing loss for that specific middle tone.
During our tone test, a patient wears a set of occluding ear muff headphones. That is, the head phones completely cover the entire ear. This ensures the patient hears the tones as well as possible. We then test one ear at a time, starting with your ear that hears better. If you feel you hear evenly in both ears, we usually start with the left ear first. On average, most people hear better with their left ear due to slightly better blood flow to the left ear. Once the tone test is completed for the better hearing ear, we then test the other ear.
During a hearing test, a tone test can be conducted with a bone oscillator. Like the headphones described above, this piece of equipment also creates tones for a patient to hear. The oscillator is placed behind the test ear and the tones travel through the bone directly to the cochlea, the main nerve center for hearing. This test provides insight about whether the patient’s hearing loss is more related to nerve loss, more related to conductive loss, or a mix of the two.
During a hearing test, you might also listen to words and sentences through headphones, through a speaker in front of you, from my voice, or from a friend or family member who attends the appointment with you. These words and sentence can be listened to with one ear at a time or with both ears at the same time. We can also introduce varying types of noise at different volumes to see how much of an impact noise has on your ability to hear. When you bring a friend or family member with you to serve as your ‘familiar voice’, we do our best to incorporate their voice into the hearing evaluation and the hearing aid demonstration.