Measuring the Extent of Hearing Loss
When a person has been diagnosed with a hearing impairment, the next step for his or her audiologist is to determine the extent of the problem. Different hearing aids and other technologies are recommended for different degrees of hearing loss, as well as different underlying causes. Despite the fact that hearing conditions are a very common problem, many people - including people who use assistive listening technology - do not fully understand how their effects are measured.
What Is a Decibel?
To understand a hearing impairment diagnosis, you first need to know how sound is measured. The answer is a mathematical unit known as a decibel (dB). The interesting thing about decibels is that they are not set amounts of energy or matter; rather, they are ratios. Specifically, a decibel is the ratio between the volume (amplitude) of a given sound and the softest sound that is audible to the average human. Decibels are logarithmic, meaning 10 dB represents a sound 10 times louder than 0 dB.
Let's consider an example. Researchers have labeled the softest audible sound 0 dB. This is a purely arbitrary label that audiologists use because it is a convenient way to understand sound. Now, consider a sound that is usually considered around 20 dB loud - for example, a soft human whisper. 20 dB is 100 times louder than 0 dB; thus, a whisper is 100 times louder than the softest audible sound.
Decibels and Hearing Loss
The degree of a person's hearing impairment is often expressed in decibels. This represents the difference between the lowest audible sound for an average person and the lowest audible sound for the person being diagnosed. For example, if a person has 10 dB hearing loss, then a sound needs to be 10 times louder than 0 dB in order for him or her to hear it.
The degrees of hearing loss are usually measured like so:
Different organizations use different scales, but most will closely resemble this one. If you are curious about the -10 in the first row, some people have such good hearing that they can hear sounds that are too soft for the average person. If their lowest audible sound is -10 dB, they are still within normal hearing range. If it is lower than that, they may actually have a condition called hyperacusis.
To learn more about ear health, contact a hearing aid consultant from HearingPlanet.
What Is a Decibel?
To understand a hearing impairment diagnosis, you first need to know how sound is measured. The answer is a mathematical unit known as a decibel (dB). The interesting thing about decibels is that they are not set amounts of energy or matter; rather, they are ratios. Specifically, a decibel is the ratio between the volume (amplitude) of a given sound and the softest sound that is audible to the average human. Decibels are logarithmic, meaning 10 dB represents a sound 10 times louder than 0 dB.
Let's consider an example. Researchers have labeled the softest audible sound 0 dB. This is a purely arbitrary label that audiologists use because it is a convenient way to understand sound. Now, consider a sound that is usually considered around 20 dB loud - for example, a soft human whisper. 20 dB is 100 times louder than 0 dB; thus, a whisper is 100 times louder than the softest audible sound.
Decibels and Hearing Loss
The degree of a person's hearing impairment is often expressed in decibels. This represents the difference between the lowest audible sound for an average person and the lowest audible sound for the person being diagnosed. For example, if a person has 10 dB hearing loss, then a sound needs to be 10 times louder than 0 dB in order for him or her to hear it.
The degrees of hearing loss are usually measured like so:
- Normal hearing: -10 to 15 dB
- Slight hearing loss: 16 to 25 dB
- Mild hearing loss: 26 to 40 dB
- Moderate hearing loss: 41 to 55 dB
- Moderately severe loss: 56 to 70 dB
- Severe hearing loss: 71 to 90 dB
- Profound hearing loss: 91 to 120 dB
- Deaf: above 120 dB
Different organizations use different scales, but most will closely resemble this one. If you are curious about the -10 in the first row, some people have such good hearing that they can hear sounds that are too soft for the average person. If their lowest audible sound is -10 dB, they are still within normal hearing range. If it is lower than that, they may actually have a condition called hyperacusis.
To learn more about ear health, contact a hearing aid consultant from HearingPlanet.
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