Post Operative Procedures

The Switch On

Within 2 to 4 weeks after surgery, the cochlear implant will be programmed and activated for the first time.

An appointment will be arranged for the initial activation session, or “switch-on”. This will take approximately 1½ hours, and will be followed by a familiarisation session with the Audiologist / Habilitationist.

The day of “switch-on” is an emotional one, and you should be prepared for both nervous anticipation and sometimes an anticlimax!. Some implantees may react with surprise, some may be excited and yet others may be shocked and wary. It is hard not to be affected by the reaction, but be reassured, whatever it is, that it is normal and will be transient. You will find that after a period of stabilisation – in some cases regression of communication skills if these were good pre-operatively - new listening and communication abilities will be acquired. You will work very closely with your habilitationist during this period, who will guide you through the process of teaching and optimising your new found capabilities.

At the “switch-on” session, your audiologist will perform a test to check the functioning of the implant, and attempt to acquire suitable stimulation levels on up to 20 individual electrodes. This is a lengthy and rigourous procedure, and will involve concentration and cooperation for up to an hour. The initial programming or “MAPping” session will be spread out in 2 sessions over 2 days, and in this time the audiologist will set a preliminary “MAP” or listening programme. In order to do this, he must obtain responses at very soft levels of sound, and ensure that the upper limits, or loudness of sound never exceeds the limits of comfort or tolerance. Behavioural responses to sound may be difficult to determine and very individual.

Following switch-on of the external device, MAPping appointments are essential to maintain optimal programming of the speech processor. MAPping is the term used to refer to the programming of the speech processor. The “MAP” refers to the level of electrical stimulation fromThe implant electrodes, which is controlled by the speech processor. The first three months after switch on is a period of frequent MAPping in order to keep up with changes in hearing caused by changing sensitivity to electrode stimulation.

The longer the implant is worn, the more stable the hearing typically is, and therefore longer periods between MAPping appointments are possible.

MAPping appointments usually take one to two hours. The switch-on procedure requires two appointments over two consecutive days. Subsequent MAPping usually requires one appointment.

The Southern Cochlear Implant Programme post-operative protocol details the schedule for MAPping appointments. These are the minimum MAPping appointments, additional MAPping sessions may be required.

A soundfield audiogram is obtained within the first month of switch-on and regularly thereafter, to determine detection of speech and environmental sounds.

 

The effect of MAPping on hearing is also monitored by standard tests of auditory perception. The major intervals for these are at one, three, six, twelve, eighteen and twenty four months after switch-on – then annually.

It is important for the programme to regularly monitor outcomes and re-MAP to ensure each individual’s hearing potential is optimised.