Saturday, 2 March 2013

Auditory Neuropathy

This is a bit confusing post just because auditory neuropathy is a confusing condition. No one should feel as confused about a diagnoses as parents of Neuropics do.
smiley Gwen

Before leaving the NICU both girls had to have ABR hearing screening, Avery passed with flying colours but Gwen got a "need to be retested" 

After a few months of ABR's when she kept waking, we knew she had a hearing issue which seemed odd. 

Gwen is bright, interactive, trying to talk, responds to sounds, and if you met her you would never think she has a form of deafness. Eventually she was diagnosed with Auditory Neuropathy, a hard day for sure because of how AN (or ANSD) behaves. A regular hearing loss is something that can be found out early, and most audiologists know how to work with it to choose hearing aids (HA) or cochlear implants (CI). But with AN you can't "tell" what they are hearing until they are older.

Wait, that is more confusing... 

A mother on the facebook group explained it this way: 

"ANSD is a type of hearing disorder that affects how the rate and consistency of the firing of nerve impulses from 1) the inner hair cells to the VIIIth (auditory nerve) when they are stimulated (one example of the site of lesion being at the location of the synapse between the inner hair cells and the VIIIth nerve)(cochlear implants would be effective in this case)
or 2) the way the "fired impulses" is travelled from one neuron cell to the next along the auditory pathway to the auditory cortex of the brain (the second example of the site of lesion being anywhere along the VIIIth/auditory nerve all the way up to the auditory cortex)(cochlear implants would not be effective in this case). 

It is the inner hair cells that need to be stimulated (or sheared by the tectorial membrane via outer hair cells for soft sounds, or touched or moved by the fluid inside the cochlea for loud sounds) in order for "neural impulses/firing" to be sent to the auditory nerve (VIIIth) which leads up to the auditory cortex of the brain. 

The neural impulses from the inner hair cells have to: a) fire at a synchronous rate (in a consistent pattern that is consistent) and b) travel uninterrupted up the auditory pathways to the brain to be received as "clear and good sound perception." 

We were also lucky that Gwen's seems to be consistent, and that hearing aids seem to be all she needs at present. She has gotten a new word a week since getting them. She is even babbling differently. She spent the first two weeks with her loner purple aids waiting on her baby pink ones to come in, and I've realized I haven't taken a pic yet of her in them. 

Gwen playing with her loner HA
Gwen with her loner HA

We don't know what is in store for Gwen with her ANSD, but we will take it as we go

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