The loudness of sound is measured in units called decibels (db). Frequency of pitch is measured in Hertz (Hz). When hearing is tested, a range of 250 Hz to 8000 Hz is measured as it encompasses the speech frequencies, the most important range for communication. This will be plotted in an Audiogram by an audiologist or a hearing care consultant.
Sometimes people give their hearing loss in percentage, for example ” I have a 60% loss of hearing in my right ear”. Measuring hearing loss in percentages is inaccurate as there will be no end of formulas to convert db into percentages. This is because the dBHL axis on the audiogram is logarithmic – each increase of 10 is actually 10 times the amount of sound pressure.
When measured together decibels and hertz tell the degree of hearing loss you have in each ear.
For each frequency that is tested, the degree of hearing loss could be different. You may also have hearing loss at more than one frequency. Hearing loss in each ear can also be different and very often is. There are just too many factors to define hearing loss as a single percentage.
Degree of Hearing Loss:-
- Average Normal hearing: -10 – 20dB
- Mild hearing loss: 20 – 40dB – one may struggle to hear speech in noisy places
- Moderate hearing loss: 40 – 70dB – difficulty understanding speech in background noise.
- Severe hearing loss: 70 – 90dB – group conversations are difficult and people would have to raise their voice.
- Profound hearing loss: greater than 90dB – you are only able to hear some loud sounds and communication is impossible at this stage.
Hearing is a complex sense that has many different facets and many different causes and degrees – it is far too complex to simplify as a simple percentage.
So next time your doctor or someone else says that you have 60% hearing loss; you will know that is an improper diagnosis.