Confirming your suspicions through an audiogramme

Audiogrammes are simple hearing tests used regularly by audiologists. I remember, as a kid, that a visiting nurse would come in to our school every couple years to test all the students' hearing; I remember putting on the headphones, listening for the tone, and raising my right hand if I heard it in my right ear, my left if I heard it in the left ear.

Typically, an audiogramme is used to check for hearing loss and deafness. As such, the test is conducted as a "spot-check." In other words, not every frequency is tested, and they only test for hearing within the typical range of hearing. This tells them IF you can hear, not HOW you hear.

A complete audiogramme will show HOW you hear. The audiogramme is plotted on two graphs, one for the left ear, one for the right ear. The vertical axis represents the decibels (volume) at which a tone is heard, and the horizontal axis represents the different frequencies we can hear. Normal, perfect hearing appears on the graph as two straight horizontal lines placed somewhere between 0-10 decibels. In other words, the quietest volume at which each frequency was heard was the same decibel, and was somewhere between 0 and 10 decibels, which is considered normal for humans.

However, people with auditory processing disorders will have mountain ranges on their graphs, instead of straight lines. AND, the mountain ranges are different mountain ranges -- they don't overlap one another. This means that the quietest the person hears (for example) the 1 kHz tone in the left ear is 5 dB, and 10 dB in the right ear, and the quietest he hears the 2 kHz tone in the left ear is 15 dB, and 5 dB in the right ear.

Someone with hypersensitivity to sounds may hear many frequencies relatively normally, but there might be one or two frequencies that are heard at -5 dB or -10 dB -- below the point at which people can normally hear! Or, they may have Uncomfortable Loudness Levels (ULL) that are quite low. In other words, he may find a frequency to be painful at only 40 dB, whereas we don't normally find sounds painful until they're over 85 dB.

If you want to confirm your suspicions that you or your child has hypersensitivities to one or more frequencies or an auditory processing disorder, ask your audiologist to conduct a complete audiogramme, testing ALL frequencies, testing down to -10dB, and testing ULL's.