Understanding an Audiometry Chart (Audiogram)
An audiogram is a graph that shows how well you can hear different pitches (frequencies) at different volumes (intensities), with each ear tested separately to create a visual map of your hearing ability. 1
Basic Structure of the Chart
The audiogram has two main axes that work together:
Horizontal axis (left to right): Shows frequency measured in Hertz (Hz), ranging from low-pitched sounds (250 Hz) to high-pitched sounds (8000 Hz). Think of this as going from bass notes on the left to treble notes on the right. 1
Vertical axis (top to bottom): Shows intensity or loudness measured in decibels (dB), typically ranging from -10 dB at the top (very soft sounds) to 120 dB at the bottom (very loud sounds). The softer the sound you can hear, the higher up on the chart your mark will be. 2
How to Read the Symbols
Each ear is marked with different symbols to keep them separate:
- Right ear: Usually marked with an "O" or red color
- Left ear: Usually marked with an "X" or blue color 2
The marks show the softest sound you could hear at each frequency tested. The lower the mark on the chart, the louder the sound needed to be for you to hear it, indicating worse hearing. 3
What Normal Hearing Looks Like
Normal hearing appears as marks clustered near the top of the chart (between -10 and 25 dB across all frequencies), meaning you can hear soft sounds easily. 1, 2
Understanding Hearing Loss Patterns
The audiogram reveals three types of hearing loss:
Conductive hearing loss: Problems with the outer or middle ear (like ear infections or wax buildup) that block sound from reaching the inner ear 2, 3
Sensorineural hearing loss: Damage to the inner ear or hearing nerve, often from aging, noise exposure, or medical conditions 1
Mixed hearing loss: A combination of both conductive and sensorineural problems 2
Common Patterns You Might See
High-frequency hearing loss (marks dropping down on the right side of the chart) is the most common pattern, especially from noise exposure or aging. This makes it hard to hear consonants in speech and understand conversations in noisy places. 4, 5
Low-frequency hearing loss (marks dropping down on the left side) can occur with conditions like Ménière's disease and affects your ability to hear vowel sounds and low-pitched noises. 1
Important Warning Signs
If your audiogram shows a difference of more than 15 dB between ears at the key frequencies (500,1000, and 2000 Hz), or if word recognition scores differ by more than 15% between ears, this asymmetry requires immediate further evaluation by a specialist to rule out serious conditions like tumors. 1
Additional Information on Your Audiogram
Beyond the basic graph, your audiogram should include:
Speech recognition scores: Shown as a percentage, this tells you how well you understand words at a comfortable volume, not just whether you can hear tones 1
Tympanometry results: Tests middle ear function to determine if hearing loss is due to fluid, eardrum problems, or other middle ear issues 1, 6
Common Pitfall to Avoid
A normal-looking audiogram does NOT guarantee normal hearing function. You can have normal pure-tone thresholds but still struggle with understanding speech in noise, processing complex sounds, or hearing in real-world situations due to central auditory processing issues that the basic audiogram doesn't detect. 7, 3