Sunday, November 6, 2011

Hearing test

Several weeks ago Abby had another hearing test, a repeat of the main test she had when she was just released from the NICU at six months old.

The typical hearing testing done on kids her age involve a sound booth, and the use of toys and lights to see what they can hear.  This doesn't really work for Abby and is very difficult to determine what she hears or doesn't hear so that her audiologist can program her hearing aids appropriately.

Since it's been about 6 years since she has had one, we felt it was time to do another ABR test:  Auditory Brainstem Response.  She had electrodes on her head hooked to a machine/computer.  Sounds were given through a tiny earphone placed inside her ears.  When a sound was presented the machine measured her brain's response and the audiologist is able to determine how soft or loud the sound needs to be in a certain frequency for her brain to give a response.

Overall this took about 3 hours.  As the audiologist read her results she stated that Abby's brain responses weren't typical and that she 'dances to her own tune'.   If only I had a dollar for every time I've heard that!

The good news is that her hearing doesn't appear to have gotten worse, which can happen.  She has a sloping severe to profound hearing loss, meaning she hears slightly better in the higher frequencies (4000 htz), creating an upward "sloping" picture on an audiogram.

To give a comparison:  typical children can hear as low as 5-15 decibels.  Abby's test showed she can hear in the 80-95 db range (500-2000 hz) with a slight rise to 65 db at 4000 hz.

Below is an Audiogram that shows on a graph what we typically hear at what frequency and decibel.

More about ABR testing for those interested:

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