What Is An Audiogram?
If you’ve ever had a (puretone) hearing test, the audiologist should have explained the results using a graphical representation, called an audiogram. Audiograms are very easy to understand, but if you have never had them explained, they may be unclear, or even confusing.
An audiogram measures both loudness and pitch of a range of normally audible puretones.
The y (vertical) axis records volume (decibels), whilst the x (horizontal) axis records frequency (Hz).
Sounds become louder as the decibel level grows (up to 140 decibels). A bird-call might measure approximately 44dB, whilst a chain saw could measure around 120dB.
The pitch becomes higher as the frequency grows (up to 8000Hz). A cat’s purring might measure approximately 125Hz, whilst a child crying could measure around 4000Hz.
0dB does not mean that there is no sound. It simply represents the quietest sound that a human (with normal hearing) would be able to detect.
Different Severities of Hearing Loss
Normal Hearing is when the quietest sounds that a person can hear measure between -10 and 20dB HL.
Mild Hearing Loss is when the quietest sounds that a person can hear measure between 21 and 40dB HL. This amount of hearing loss typically occurs around the age of 40-50 years of age. People with mild hearing loss are often unaware that they have a loss, as their thresholds fall within the Speech Banana, and so conversing has not yet been dramatically affected. Mild hearing loss is often identified by family or friends, especially if female (higher pitched voice).
Moderate Hearing Loss is when the quietest sounds that a person can hear measure between 41 and 70dB HL. This normally occurs between 51-70 years of age. Moderate hearing loss begins to effect the interpretation of speech and other quiet noises and often signifies when the hearing loss begins to adversely affect one’s quality of life. People often begin to rely on lip reading or body language.
Severe Hearing Loss is when the quietest sounds that a person can hear measure between 71 and 95dB HL. This normally occurs between 71-80 years of age. Severe hearing loss begins to affect more general noises, such as road traffic. General quality of life, if unassisted, can begin to deteriorate. People become heavily reliant on lip reading or body language.
Profound Hearing Loss is when the quietest sounds that a person can hear measure over 96dB HL. People are unable to hear the majority of day-to-day sounds, unless exceptionally loud. Lip reading, sign language or other communication tactics are essential to communicate, and the possibility of surgical intervention (cochlear implantation) arises.
