Understanding Your Audiogram: A Patient's Guide

An audiogram is a graphical representation of your hearing ability. It is the primary tool used by audiologists to visualize and quantify your hearing thresholds at different frequencies. Think of it as a map of your hearing. At our private audiology clinic in High Wycombe, Loudwater, we use state-of-the-art equipment to generate a precise audiogram, which forms the basis of our diagnostic process and treatment recommendations. This detailed chart allows us to understand the specific nature of your hearing loss and tailor a solution that is unique to you.

The audiogram has two main axes. The horizontal axis (x-axis) represents frequency, measured in Hertz (Hz). This is often referred to as pitch. On the left side of the graph, you have low frequencies, like the sound of a bass drum or a tuba. As you move to the right, the frequency increases, representing higher-pitched sounds, like a bird singing or a whistle. The typical range tested is from 250 Hz to 8000 Hz, which covers the majority of speech sounds.

The vertical axis (y-axis) represents intensity, or loudness, measured in decibels (dB). The top of the graph is 0 dB, which represents the softest sound a person with normal hearing can detect. As you move down the graph, the sound gets louder. Each mark on your audiogram indicates the softest sound you can hear at that specific frequency, known as your hearing threshold.

During your hearing test, we test each ear individually to get a complete picture of your hearing health. The results for your right ear are typically marked with a red ‘O’, and the results for your left ear are marked with a blue ‘X’. These symbols are connected to form lines, creating a visual representation of your hearing thresholds across different frequencies.

These ‘O’ and ‘X’ symbols represent your air conduction thresholds. This is how you normally hear, with sound traveling through your outer and middle ear to the inner ear. We may also test your bone conduction, which bypasses your outer and middle ear to directly stimulate the inner ear (cochlea). These results are marked with a ‘<’ for the right ear and a ‘>’ for the left ear. Comparing air and bone conduction results is crucial for diagnosing the type of hearing loss.

By comparing the air and bone conduction results, we can determine the type of hearing loss you have. This is a critical step in formulating an effective treatment plan at our High Wycombe clinic.

• Sensorineural Hearing Loss: This is the most common type of hearing loss and occurs when there is damage to the inner ear (cochlea) or the auditory nerve. On an audiogram, both air and bone conduction thresholds are at similar, reduced levels, indicating a problem in the inner ear. This type of loss is typically permanent but can often be successfully managed with hearing aids.
• Conductive Hearing Loss: This occurs when sound is not conducted efficiently through the outer or middle ear. Common causes include earwax buildup, fluid in the middle ear, a perforated eardrum, or problems with the small bones in the middle ear. On an audiogram, there is a gap between the air and bone conduction thresholds (an air-bone gap), with bone conduction being better than air conduction. Many cases of conductive hearing loss can be treated medically or surgically.
• Mixed Hearing Loss: This is a combination of sensorineural and conductive hearing loss. There will be an air-bone gap, and the bone conduction thresholds will also be outside the normal range.

The severity of your hearing loss is determined by your hearing thresholds in decibels. This classification helps us explain the real-world impact of your hearing loss and what sounds you might be missing.

In addition to pure-tone testing, your audiologist will conduct speech audiometry. This assesses your ability to hear and understand spoken words at different volumes. You will be asked to repeat words presented at various loudness levels. The results, known as a Speech Recognition Score (SRS) or Word Recognition Score (WRS), are crucial for determining the real-world impact of your hearing loss and for the successful fitting of hearing aids. A high score indicates good clarity, while a lower score might suggest that even when sounds are made louder, they are not necessarily clearer. This is an important consideration when discussing expectations for hearing aid use.