What is Normal Hearing?

You had your hearing checked a few years ago and you were told at that time that you had normal to borderline normal hearing. You think it might be time to have it checked again because you’ve been noticing that you don’t hear as well as you used to.  You’re also wondering how you could’ve had normal to borderline normal hearing.  Exactly what is “normal” hearing?

Part of the test that we do involves having you listen to a series of tones at different intensity (volume) levels measured in decibels and at different frequency (pitch) levels measured in hertz .  From your responses we get an overall picture of your hearing threshold levels across the range of frequencies that correspond closely to the region in which speech occurs.

Below is a table.  The table below shows one of the more common systems we use to classify hearing levels. The numbers are representative of a patient’s range of hearing levels in decibels (dBHL).

Degree of hearing loss      Hearing loss range (dBHL)

Normal                                   –10 to 25

Mild                                         26 to 40

Moderate                                41 to 55

Moderately severe                  56 to 70

Severe                                    71 to 90

Profound                                91+

Yes, you’re reading that correctly the range above for “normal” hearing is from (-10dBHL to 25dBHL). (Zero) 0dBHL does not mean that there is no sound at all. Rather, it is the softest sound that a person with “normal” hearing ability would be able to detect at least 50% of the time. Most audiograms begin below 0.  Since 0dBHL is the softest sound that the average normal hearer can detect there are plenty of people who have hearing levels that are above average (meaning they can detect sounds below 0dBHL).

The measurement of a decibel can be a little confusing.  A decibel is a unit used to express relative difference in power or intensity.  On the decibel scale 10 dBHL is 10 times more powerful is 0 dBHL. A sound 100 times more powerful than 0dBHL is 20 dBHL. A sound 1,000 times more powerful than 0dBHL is 30 dBHL.  A drop in your hearing levels from 10dBHL to 30dBHL is a big change.

Your takeaway from all this should be how your ability to hear is impacting your life.    If you had your hearing checked 5 years ago and your threshold levels were at 10dBHL and they’ve now declined to 30bHL that change is going to be quite noticeable to you.    If you’re an active person who enjoys spending time with friends and family, this change in your hearing levels from the “normal” range to just entering the “mild” range may be so bothersome to you and everyone around you that you’re ready to do something about it immediately.

• Do you have a problem hearing over the telephone?
• Do you have trouble following the conversation when two or more people are talking at the same time?
• Do people complain that you turn the TV volume up too high?
• Do you have to strain to understand conversation?
• Do you have trouble hearing in a noisy background?
• Do you find yourself asking people to repeat themselves?
• Do many people you talk to seem to mumble (or not speak clearly)?
• Do you misunderstand what others are saying and respond inappropriately?
• Do you have trouble understanding the speech of women and children?
• Do people get annoyed because you misunderstand what they say?

If you answered yes to 2 or more of the following, chances are that even if your hearing levels have just begun to drop out of the range of normal, it’s impacting your quality of life and it’s time to do something about it sooner rather than later.

For more information, visit our website http://www.newtonhearing.com/