What is an Audiogram and Why is it Important?
As an ENT specialist, I often meet patients who need hearing tests but aren't quite sure what to expect. One of the most common tests you’ll hear about is the audiogram. It's a chart that shows the results of your hearing test, which helps us understand how well your ears are working. Let’s break it down in simple terms so you can better understand what an audiogram is, why we do it, and how to interpret the results.
Understanding your audiogram results can lead to early intervention, which is essential for maintaining good hearing health and improving quality of life. Whether it's for a child struggling in school due to undiagnosed hearing loss or an adult noticing the early signs of hearing impairment, an audiogram is the first step towards effective treatment.
We conduct an audiogram when there are signs of hearing problems, such as:
- Difficulty understanding conversations, especially in noisy environments.
- Frequently asking people to repeat themselves.
- Ringing in your ears (tinnitus).
- Ear infections or discomfort.
- A sudden loss of hearing.
The test helps us understand what kind of hearing loss you might have—whether it's temporary (due to an ear infection or wax buildup, for example) or more permanent, as sometimes happens with age or noise exposure.
The Key Components of an Audiogram: Breaking It Down
An audiogram is a graphic representation of your hearing ability. It’s used to check how well you can hear sounds at different pitches (frequencies) and volumes (intensities). The test is important because it helps us figure out if you have hearing loss, and if so, how severe it is. Let's break it down into its different sections:
Pure Tone Audiometry:
This is the main part of the hearing test. It measures your ability to hear sounds at different pitches (like a high-pitched whistle or a deep drum). The goal is to find the quietest sound (or threshold) you can hear at each frequency. This threshold is recorded on the audiogram, and it tells us how well sound is traveling through your entire hearing pathway—from your outer ear to your inner ear.
The results are plotted on a graph (the audiogram), with the frequency (pitch) on the horizontal part of the graph (top or bottom) and volume (loudness) along the side. A healthy ear will show good hearing at low volumes across all pitches. In other words, the lower the thresholds on the audiogram, the worse the hearing. As an example, 20 decibels is the sound level of a whisper while 90 decibels is the sound level of a food processor
Speech Audiometry:
This part tests your ability to understand speech, not just hear sounds. You’ll listen to words or sentences and repeat what you hear. This helps us measure two things:
- Speech Reception Threshold (SRT): The softest level at which you can correctly identify words. You will be presented with spondee words, which are words that contain only two syllables (with equal emphasis on both syllables) like "baseball" or "hotdog", and you'll have to correctly repeat them.
- Word Recognition Score (WRS): How well you understand words at a comfortable listening level (that level was determined by the SRT above). A list of single syllable words is presented at a comfortable loudness level, often around 25 to 50 words, to assess how clearly you understand speech without needing to adjust the volume. You score (a pourcentage) will represent the number of correctly identified words out of the total list.
Speech audiometry is important because even if you hear sounds, understanding speech—especially in noisy environments—can be challenging.
Tympanometry:
A test that checks how well your eardrum moves in response to changes in air pressure. It’s like when you pop your ears on a plane or when you yawn. The test involves placing a small probe in your ear that gently changes the air pressure, and we measure how your eardrum responds. It feels a little strange, but it’s painless. The result is a pressure-volume curve, which shows how the eardrum moves as the air pressure changes. "Compliance" refers to how flexible or stiff the eardrum is—higher compliance means the eardrum moves easily, while lower compliance means it’s stiffer. This test helps us figure out if there are problems with your middle ear, like fluid buildup or issues with the small bones behind the eardrum.
The Process: How Audiograms are Conducted
Conducting an audiogram is a straightforward and non-invasive process. Here's how it typically works:
- Preparation: You'll be seated in a soundproof room or booth to ensure accurate results. The audiologist will first check if your ears are clear from obstruction such as wax. If it's the case, your ears will be cleaned. Headphones, ear inserts or bone oscillators are then placed in/behind your ears to deliver the test sounds.
- Pure Tone Audiometry: You'll listen to a series of tones or beeps at different frequencies and volumes. Your task is to indicate when you hear each sound, usually by pressing a button.
- Speech Audiometry: You'll hear words or sentences through the headphones and be asked to repeat them.
- Tympanometry: A small probe is inserted into your ear canal to change the air pressure and measure eardrum movements. This part of the test is quick and painless.
A report is then generated and sent to you and/or your healthcare provider.
The examination can take anywhere from 30-90 minutes to complete depending on many factors.
Interpreting Your Audiogram:
1) What do the results mean?
The audiogram graph displays your hearing thresholds across different frequencies, typically ranging from 250 Hz to 8000 Hz. The audiogram chart may look confusing at first, but here’s what to focus on:
Frequency (Pitch): The horizontal axis shows the pitch of the sound, from low to high. Low-pitch sounds might be like a drumbeat, while high-pitch sounds are like a whistle. The unit of measurement is called a "Hertz".
Volume (Intensity): The vertical axis shows how loud the sounds need to be for you to hear them, with the softest sounds at the top and the loudest at the bottom. In other words, the lower you are on the graph, the worse the hearing. The unit of measurement is the decibel (dBHL). For example, 20 decibels is the sound level of a whisper while 90 decibels is the sound level of a food processor.
Hearing Levels (or thresholds): They represent the "points" on the audiogram graph, which indicate the quietest sound you can hear at each frequency. Different symbols have different meanings, here are the most common ones:
| Test | Right ear | Left ear |
| Air conduction (unmasked) | O | X |
| Air conduction (masked) |  |
|
| Bone conduction (unmasked) | < | > |
| Bone conduction (masked) | [ | ] |
| No response | ↘ | ↙ |
When talking about hearing thresholds, it is important to look at both the air conduction levels, the bone conduction levels and the air-bone gap (see section below) to determine the type of hearing loss. The severity of the hearing loss is always determined using your air-conduction levels. Your hearing thresholds are plotted on the chart. Normal hearing is typically between 0 and 25 decibels (dBHL). If your results are below this range, you might have some degree of hearing loss
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- 0-25 dB: normal hearing (some professionals consider 0-15 dB as normal hearing, and add the category 15-25 dB as very mild hearing loss)
- 26-40 dB: Mild hearing loss.
- 41-55 dB: Moderate hearing loss.
- 56-70 dB: Moderate-to-severe hearing loss.
- 71-90 dB: Severe hearing loss.
- Over 90 dB: Profound hearing loss.
Speech audiometry results are often presented as percentages, with a higher percentage meaning you can understand speech better at normal conversation levels.
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- 90-100% WRS (word recognition score) = excellent discrimination
- 70-90% WRS = very good discrimination
- 50-70% WRS = moderate discrimination
- less than 50% WRS = poor discrimination
2) Hearing levels: A Closer Look at Air and Bone Conduction
Pure tone audiometry is a key part of the hearing test, and it helps us evaluate how well you can hear different tones or pitches. As we mentioned above, we use two types of measurements: air conduction and bone conduction. Each one provides different information about how sound is traveling through your ears and where a potential hearing problem might be located.
Air Conduction
Air conduction refers to the way sound travels through the air into your ear canal, through the eardrum, and into the middle and inner ear. This is the natural way we hear most sounds in everyday life.
How Is Air Conduction Measured?
During the air conduction test, you'll wear a set of headphones (or insert earphones) that deliver sounds directly into each ear. You’ll hear a series of beeps or tones at different frequencies (pitches) and volumes (loudness). Each time you hear a sound, you’ll be asked to press a button, raise your hand, or give some kind of signal to show that you heard it.
What Does It Tell Us?
Air conduction testing gives us a good idea of your overall hearing ability, and represents what you actually hear. If there’s a problem with any part of the hearing pathway (e.g., wax buildup in the ear canal, a perforated eardrum, or issues with the tiny bones in the middle ear or in the inner ear itself), it will show up here as hearing loss. However, air conduction alone can’t tell us exactly where the problem is; it cannot distinguish whether there is a mechanical issue or a hearing nerve issue. That’s where bone conduction comes in.
Bone Conduction
Bone conduction is another way sound reaches your inner ear, bypassing the outer and middle ear. Instead of sound traveling through the ear canal, eardrum, and middle ear bones, the sound vibrations are delivered directly to the cochlea (the inner ear) through the bones of your skull. This represents your potential hearing.
How Is Bone Conduction Measured?
In this test, a small vibrating device called a bone oscillator is placed behind your ear on the bone (called the mastoid bone). This device sends sound vibrations directly to your inner ear, bypassing the outer ear and middle ear. You’ll hear similar beeps or tones as in the air conduction test, and again, you’ll respond when you hear them.
Bone conduction is measured at the same frequencies as air conduction, and your results are plotted on the same audiogram.
What Does It Tell Us?
By comparing the results of the air conduction test and the bone conduction test, we can pinpoint where hearing loss might be occurring. This article explains the various types of hearing loss.
- Normal bone conduction and normal air conduction: indicates normal hearing; your actual hearing (air conduction) matches your potential hearing (bone conduction), and their respective symbols are overlapping on the graph.
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Normal bone conduction and abnormal air conduction: This indicates conductive hearing loss, meaning the problem is in the outer or middle ear (e.g., earwax, ear infections, fluid, or problems with the eardrum or middle ear bones). The symbols for air conduction and bone conduction are not overlapping: there is a gap between them, called air-bone gap. The inner ear is working fine, but the sound isn’t getting through the outer or middle ear properly. Your potential hearing (bone conduction) is better than your actual hearing (air conduction). Surgical treatment could be offered.
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Abnormal bone conduction and abnormal air conduction, with overlapping results (no air-bone gap): This indicates sensorineural hearing loss, meaning the problem is in the inner ear (cochlea) or the hearing nerve itself. Your actual hearing (air conduction) matches your potential hearing (bone conduction), and their respective symbols are overlapping on the graph but in the abnormal range of hearing. This type of hearing loss can happen due to aging, exposure to loud noises, or damage to the inner ear’s delicate structures.
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Abnormal bone conduction and abnormal air conduction, AND with an air-bone gap: This can indicate a mixed hearing loss, meaning there’s a combination of conductive and sensorineural issues. For example, there could be a middle ear infection along with some age-related hearing loss.
Why Do We Measure Both?
By measuring both air and bone conduction, we can get a complete picture of your hearing health. Air conduction tells us how well sound travels through the entire hearing system, while bone conduction lets us focus on the inner ear. The difference between the two tests helps us figure out exactly where the hearing loss is happening and what type of treatment might be most effective.
For example:
- Conductive hearing loss (e.g., caused by earwax, infections, or fluid in the ear) might be treated with medications, ear cleaning, or minor surgery.
- Sensorineural hearing loss (often due to age or noise exposure) may require hearing aids or other assistive devices, as it’s typically a permanent form of hearing loss.
- Mixed hearing loss will require a combination of treatments addressing both the conductive and sensorineural aspects.
In conclusion, pure tone audiometry is a critical part of diagnosing hearing loss. By measuring both air and bone conduction, we can determine not only if you have hearing loss, but also the type and severity. With this information, we can tailor the next steps, whether that involves medical treatment, hearing aids, or other interventions.
3) Tympanometry: Understanding the Various Curve Types
Tympanometry results show us how your eardrum moves, and the different types of results help us understand how healthy your middle ear is.
Type A result means your eardrum is moving normally, which indicates a healthy middle ear.
Type As shows a "shallow" curve, meaning the eardrum is stiffer than normal, often due to something like scarring or early otosclerosis.
Type Ad is the opposite—it shows a very "deep" curve, meaning the eardrum is too flexible, which could happen if the tiny bones behind the eardrum are dislocated.
Type B means the eardrum isn’t moving at all, which might be due to fluid in the middle ear or a perforated eardrum.
Type C indicates the eardrum is being pulled inward, often due to pressure problems like eustachian tube dysfunction, such as during a cold or allergies.
Next Steps After Getting Your Audiogram Results
Once you have your audiogram results, the next steps are crucial for your hearing health:
- Consultation: Discuss your results with your ENT specialist, audiologist or hearing aid specialist. They will help you understand the implications and recommend appropriate treatment options.
- Treatment Options: Depending on your hearing loss type and severity, you may be a candidate for surgical treatment, or might need hearing aids, cochlear implants, or other assistive devices. Early intervention can make a significant difference in managing hearing loss.
- Follow-Up: Regular hearing check-ups are essential to monitor any changes in your hearing ability and adjust your treatment plan as needed. Consistent follow-up ensures you maintain the best possible hearing health. After diagnosing a new case of hearing loss, I typically advise scheduling a follow-up audiogram every 1-2 years to monitor any changes in the condition over time.
Final thoughts
An audiogram is a simple but powerful tool that helps us understand your hearing health. Whether you’re noticing hearing difficulties or just want to check how well your ears are working, a hearing test is a great way to ensure you’re taking care of one of your most important senses. If you have concerns about your hearing, don’t hesitate to reach out to an hearing health expert for further evaluation.
Remember, early detection of hearing issues can make a big difference in improving your quality of life!
Joe Saliba, MD
Dr. Joe Saliba is an ENT surgeon specialized in neuro-otology and medical director at ODYO. He treats patients with various ear and skull base disorders, ranging from hearing loss and vertigo to vestibular schwannomas and cochlear implants.
