What is an audiogram and what does it test for?
The world of audiology can be a little confusing at times due to the names used to describe our field! I am going to break down what an audiogram is in this article which will hopefully make your first visit with an audiologist a little less overwhelming. An audiogram is the name of the graph used to depict someone’s hearing abilities. This graph tells us what the person was able to hear during their evaluation, their word recognition abilities, and contains other important information about their anatomy and the physical properties of hearing.
How is the audiogram performed?
The day of your appointment the audiologist will first review your medical history, ask you any clarifying questions, and answer any questions you might have before starting the testing. Otoscopy is the examination of your outer and middle ear, where the audiologist will look with their otoscope, or ear light, into your ear canal. If cerumen, or wax, is found, it may need to be removed prior to having your hearing tested. Cerumen can be removed either using water or with special tools to help grab the wax and pull it out of the ear canal. Once your ear canals are clear, you will have your hearing tested in a special room, called a sound booth. This booth allows for a fair assessment of your hearing without outside distractions. The audiologist will place either foam insert eartips or over the ear headphones in/on your ears. Often, you are given a push button or asked to raise your hand every time you hear a stimulus presented, such as a beep. This is how the audiologist will record that you are hearing the sounds presented to you. These steps are repeated at each frequency several times to ensure the correct response was recorded. It is important to push the button every time you hear the stimulus, even if it is very quiet. We are looking for the softest sound you can hear, therefore we do not want you to wait until you can clearly hear the sound. It is also important to not continuously push the button even when sounds are not being presented, as this can extend the time of the evaluation and give inaccurate results of your hearing.
The audiogram graph has frequencies arranged from low frequencies to high frequencies running from left to right on the image. The graph has loudness increments, known as decibels, running from very quiet to very loud sounds, arranged from top to bottom. The audiogram uses red Os to describe the responses of the right ear and blue Xs to describe the responses of the left ear. The Xs and Os represent the softest responses, or threshold, of the frequency tested that the person can hear. Those scores represent what is called the “air conduction score.” Air conduction is how you hear the world around you normally. A sound is produced, a sound wave moves through the air, traveling from your outer ear, into your ear canal, through your eardrum or tympanic membrane, and into your inner ear, or cochlea.
Another set of scores you will see on an audiogram are “< / >” or “[ / ]” ; these symbols represent a “bone conduction score.” Bone conduction is the process by which you hear through vibrotactile methods. A tight band is placed on the bony bump on the back of your head, often the mastoid. Sound is played to the processor which then vibrates the skull. The skull conducts or sends those vibrations directly to the cochlea! The softest level or threshold is marked on the audiogram. The correlation between air conduction and bone conduction allows us to know where pathology of hearing loss occurs IF hearing loss is present.
The final portion of the audiogram is speech testing. Speech testing should be performed via recorded voice for best practices and outcomes. The evaluation will first evaluate the threshold, or softest two-syllable word the person can hear. Think of this test like limbo, how low can you go! We want to establish the softest level that your brain can hear and interpret the word it was presented. Secondly, we will add 40dB of sound to that level and present a word list to measure word recognition. You will hear a man’s voice say: “Say the word….” and then you will hear a tiny word at the end. The person completing the test needs to repeat the tiny word back to the audiologist as best as they can. The results will be calculated and scored on the audiogram.
What are the benefits of getting an audiogram done regularly?
There can be other tests that make up a hearing evaluation based on your case history, but an audiogram specifically, consists of air conduction testing, bone conduction testing, and speech testing as described above. Sometimes your provider may test speech in noise, run a tympanogram, which is a measurement of your middle ear space and eardrum movement, or complete a test called an OtoAcoustic Emission! There are other options but those are commonly performed tests you may see during a hearing evaluation.
Once the testing is complete, your audiologist will discuss and review your results with you. In a private practice setting those results are often reviewed the same day and time as your appointment. When discussing hearing loss, the audiologist will tell you the severity and type of hearing loss. Severities can range from mild to profound and hearing loss has three types: sensorineural, conductive, or mixed. Sensorineural hearing loss is permanent hearing loss with damage to the inner ear, cochlea. Conductive hearing loss occurs when something in the outer or middle ear is blocking sound from passing, and can sometimes be resolved. Mixed hearing loss is a combination of sensorineural and conductive hearing loss.The audiologist will discuss the different parts of your test results and correlate those into your personal listening situation based on the information you shared during your intake questionnaires and case history. If you have any potential medical concerns with your hearing loss, your audiologist will recommend a referral to an Ear Nose and Throat, ENT, physician to rule out any medical management needed. If you have no medical contraindications which would prompt you needing a referral your audiologist will most likely recommend hearing aids as part of a treatment plan to correct your hearing loss. Generally, annual or every other year, hearing evaluations are recommended to be repeated. This allows your audiologist to monitor the progression of your hearing loss and word understanding. We expect hearing loss to change very slowly over time. If we see alarming downward shifts or an asymmetry develops we will refer you to an ENT for medical evaluation.
If hearing aids are recommended and you proceed with the fitting of the devices, there is an acclimatization period to wearing hearing aids. It is not a difficult period but the hearing aid process is a two-sided relationship in that your audiologist will work through listening goals with you and you will need to work on your end of listening goals also! Hearing aids don’t just get placed in your ear and then magically everything is clear, like we experience with glasses. It does take your brain time to adjust to the new sounds and experiences around you. Once you complete the first few weeks with hearing aids the process is usually comfortable and easy to wear your “new ears!”