So, what is a bionic ear / an ABI ?
The implant is similar in external appearance to a cochlear implant which most people have heard of but the internal workings are very different. A cochlear implant works by inserting a coil into the cochlear which then interprets signals received from an external microphone and sends these to the auditory nerve. With fused auditory nerves the device is useless as the sound can’t get through.
An auditory brainstem implant (ABI) is a small (4mm long) paddle with 12 electrodes The paddle sits on the brainstem that the cochlear vestibular nerve attaches to. The brainstem is at a sloping angle and therefore the surgeon has to place the implant in at an angle. The brainstem itself is about 5mm long and therefore requires very steady hands and a skilled surgeon to carry out the surgery. The surgeon will use electric acoustic brain response (EABR) testing to check the placement whilst still in theatre. We have seen a few videos of this procedure and its very tricky. Theo had his first EABR on 22/12 and was not right for a few weeks after so I am concerned about this.
About 6-8 weeks later (once the swelling on the brain has gone down) the implant will be activated. Theo will need to stay in Italy all this time for daily check ups to make sure wound is healing etc. This is done in hospital as there will quite often be other parts of the body that react to the neuro stimulation. We have been told that over half the electrodes can cause a non auditory response – a tingling toe, cough etc. They will turn off any that cause discomfort and can also turn up or down the electrodes depending on the results that they achieve. We will be very reliant on signals and cues that Theo can give us to determine what he is experiencing. With Theo being so little this will be hard and will require 24/7 observation. From then on there will be further mapping sessions, carried out in specialist audiology centres to fine tune the device to give Theo the best possible access to sounds. For the first 12 months this involves lots of flights to Itlay but we are hoping that the NHS will take over his mapping sooner than this and have put the question to the team in Manchester so fingers crossed.
Externally Theo will have a processor which is like a cochlear implant processor. This will pick up external sounds via a microphone and then convert these into signals for the neuro stimulators in the implant. It isn’t the same as the sounds you or I hear but with a young brain he should be able to interpret them just as we do with extensive training with a qualified audiologist. At the very least Theo will be able to hear normal every day environmental sounds and this will assist him greatly with lip reading and speaking. The optimum result is that he will be able to access “open set speech” which will be more than I could ever have hoped for and that is what Professor Colletti is aiming for. 35.7% of his patients have achieved this. This for us would be a miracle