By Liz Kobylak, HLAA-MI Hearing Technology Resource Specialist
Those of us who have been diagnosed with hearing loss have probably, at some point, looked with dread at our audio- grams which graph our hearing test results. This graph can be confusing to those just beginning their hearing loss journey. To understand the basics of how to read an audiogram we need to become familiar with a few terms related to hearing loss.
- Air Conduction: hearing test signal (tones or speech) through the headphones.
- Bone Conduction: hearing test signal (tones or speech) through a vibrating tool called the oscillator placed on the mastoid bone behind the ear.
- Decibel (dB): unit of measurement for sound. This is a logarithmic measurement, not a linear one.
- Frequency: pitch or tone, measured in Hertz (Hz).
- Masking: a noise signal used to keep one ear “busy” while testing the other ear.
- Threshhold: the softest level of a puretone to which a person responds 50% of the time.
- Speech Reception Threshhold: the softest level at which a person correctly repeats two-syllable words 50% of the time.
- Speech Discrimination: Testing with words at a comfortable level of loudness to identify problems with speech understanding beyond what is expected for the hearing loss.
- Sensorineural loss: hearing loss which occurs in the cochlea (sense organ) or beyond (neural).
- Conductive loss: hearing loss with better test results from the oscillator, generally means signal is being blocked in the canal or middle ear.
- Mixed loss: hearing loss with a sensorineural and conductive component.
Now let’s take a look and become familiar with the audiogram:
- The numbers along the left side of the chart measure decibels (dB). The higher the number, the louder the This is not a linear scale, it is logarithmic.
- The numbers along the top of the chart measure frequency or pitch of sound in Hertz (Hz). Think of this part as a piano keyboard with the lower pitch sounds on the left of the The sounds become higher in pitch as you move to the right.
- The right side of this chart shows various levels/categories of hearing
- Right ear air conduction threshholds are marked with a “O”
- Left ear air conduction threshholds are marked with an “X”
- The audiologist may mark the threshold results for the Right ear with RED ink and for the Left ear with BLUE
- Right bone conduction results are marked with this “
- Left bone conduction results are marked with this “>“
Asking for a copy of your audiogram is a good idea. It can be an important step in becoming empowered about your own unique hearing loss. It is, after all, a health condition that varies between individuals. Many patients find it useful to plot their own audiogram test results onto the blank audiogram to help identify their level of hearing loss. The individual test results can also be plotted onto the audiogram of familiar sounds. In either case, remember that everything above the lines of the connected O’s or X’s is what the patient cannot hear. This is a significant step toward understanding why we hear some sounds but do not hear others in daily life.
- Even a mild hearing loss (30-40 dB range) can impact speech
- A moderate hearing loss (50 dB) indicates that most speech sounds are already being
- People with a severe hearing loss (71 dB) have lost all ability to hear speech
- Keep in mind that vowels are lower in frequency than Many words begin or end with conso nant sounds. People with hearing loss can miss whole syllables and speech can sound garbled as a result.
- The human voice can make vowel sounds louder but not consonant This can lead to distortion of speech when people try to speak very loudly to some- one with hearing loss. (To demonstrate, try making the “s” sound as loudly as you can.)
- The chart at the left is a great tool to educate oneself as well as family and friends about the real life implications of our hearing
Becoming familiar with some of the terms associated with hearing loss allows patients to participate in their hearing health care from the very beginning. Audiologists will gladly explain the nuances of your unique hearing loss.
In my own case, there is a sense of empowerment that comes with being able to tell people that I have severe to profound hearing loss in both ears, instead of just saying I have a hearing loss. Showing the audiogram of familiar sounds to my family really opened up their eyes (and in some cases, dropped their jaws) about how little I am actually able to hear without amplification. Knowledge is power.
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