Thursday, October 15, 2009

Audiowhat?

Audiogram...
An audiogram is a chart or graphic record that is used to record a person's abiltiy to hear sound at certain decibel and frequency levels.
When a person suspects hearing loss, they undergo testing with an audiometer.  I often refer to this as "the box." You go inside a sound proof room, put on the provided head phones, and raise your hand or push a button when you hear the beep.  Each beep is delivered at a different frequency and decibel level.  A decibel is simply a unit used to express the intensity of a sound wave.  The louder the sound, the higher the decibel number.  Speech comes in around 20-50 decibels, leaves rustling-20 decibels, a nightclub or concert is around 110, a hair dryer, about 80.
Take a look at the audiogram below...most of them don't come in rainbow colors but I wanted to show you a few extra things.

The numbers on the left are decibels from soft to loud going down; the numbers across the bottom are frequencies from low to high.
You can see where I boxed in 20-50 to show you where normal speech falls on the sound chart.  Notice the letters on the chart in the blue section.  These are called phonemes, or more simply put, sounds letters make.  You can see that M is around 35 decibels, O is 40 decibels and 750Hz, etc.
I colored the chart to show you the different levels of hearing loss.  A person with normal hearing would fall into the pink area and be able to hear all sounds below it. 
The vertical lines show frequency levels.  Look at the black hand drawn line with the Xes at the top of the chart.  This is what a normal audiogram would look like.  At each frequency, the person raised his or her hand at the beep and the audiologist drew an X.  If the person being tested fails to raise his hand or push a button, the audiologist raises the decibel until the patient can hear it, finally marking an X at the correct level.
The red Xes are mine; I can hear all sounds below my line.  As you can see, my hearing levels are well below the normal speech threshold; you need to be as loud as a hair dryer or vacuum for me to hear you.  My loss is considered moderate to severe.  Without amplification, I am pretty much useless.  I can hear men better than women since their voices are usually lower.  You can see that my Xes take a dip as the frequency increases before coming back up with the really high frequencies.
People who have even a mild loss should consider hearing aids since most speech occurs at that level.  I'm trying to get the courage together to go a whole day without using mine just to see what happens.  When I finally do, I'm sure I'll blog about it!  I'm also curious to see what an audiogram with my hearing aids would look like, definitely not normal, but I'm thinking mild to moderate.

2 comments:

  1. I'm sure it's no fun for you, but what a wonderfully informative blog! I'd like to advertise it on my blog. I write poetry about blogs that interest me, and give your blog URL at the same time. I'm going to be writing for 'Colour Carnival' this week and I'd like to feature your colourful chart. May I? Check me out at my blog'

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  2. Thanks! I'd love that. Be sure to send me the link so I can post it up here.

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