Well its been 3 months since activation and I thought I would provide an update. I have experienced several things:
- Insertion was completed and no translocation occurred. The array is located where it should be.
- Per the hospital’s practice the initial mapping was the default one and the ABF mapping from the CT scan was installed later and is now being used. The quality is much better. It showed all frequencies to be a bit lower based on location.
- I have determined that I in fact have some residual hearing but it is primarily at low frequencies (<500 Hz). So the sounds of my pulse, ear pops or ear tap were being picked up at the apix region.
- An audiogram of my implanted ear showed almost a complete match to the pre-op test! However the volume is much lower and still no sound in the higher frequency areas where the array resides. This leads me to question the value of audiograms to measure hearing capacity.
- Progress towards understanding words and sounds improves, but slowly. The most noticable change has been the ability to hear higher frequency sounds. Outside noises, phone ringing or the kids voices are much clearer.
I was prepared for the possibility of loss of residual hearing. That said, I was surprised that this has occurred despite every effort to preserve it - selection of a lateral array that was inserted completely within the ST, use of very slow and steady robotic insertion and use of steroids to reduce inflammation. I have yet to hear an explanation about why most of my natural hearing was lost. Given that so much of the effort by manufacturers of these systems has been directed to improving the quality of hearing including preservation of natural hearing, I have the sense that even after all this effort, they have a poor understanding about the factors that affect this.
For those who are considering a CI who have some level of natural hearing, the idea they could lose all this for a benefit that comes with significant change in their hearing experience, requires a leap of faith. Maybe saying that the technology has improved to the point that residual natural hearing will likely be retained helps them with this even if it not likely.
On balance though I am happy I made this change as the net benefits are positive and noticeable,