Guide to Cochlear Implants
Because the new generation of implant devices allows different MAPs to be placed in the assorted program slots in the speech processor, parents can change programs at home without returning to the implant center. During the interval between mapping sessions at the center, parents are responsible for monitoring the child’s performance over time with each of the programs. Changing from one program to the next often requires just pressing a button, turning a control dial, or moving a toggle switch. When parents switch from one MAP to the next, several performance outcomes are possible. There may be no change, a positive change, or a negative change in the auditory or speech skills of the child. If parents do not observe immediate changes, they should continue to use the new MAP with the expectation that changes will occur after longer periods of wear time. If parents observe an immediate positive change that results in improved performance, they should note these changes for the programming audiologist. This provides important feedback that can be used during subsequent mapping sessions. Some implant centers use forms and questionnaires to collect this information. (See figure 5.2.) Finally, if parents observe a negative response (either a decrease in performance or an adverse response), they should return to a previously acceptable program and contact the implant facility.
Each implant is powered by either rechargeable or alkaline batteries. Some devices use “AA” batteries while others use lithium batteries or the traditional hearing aid button battery. Regardless, parents must be aware of the approximate life of the battery, the recharging procedure (if using rechargeable batteries), and the importance of carrying extra batteries.
Battery life varies with the type of speech processing program, the amount of wear time, and the volume settings on the processor. Certain speech processing programs require larger amounts of power. For the body processors, average battery life is approximately twelve to fifteen hours if using rechargeables, and almost twenty-four hours if using alkaline. For BTE speech processors, battery life varies greatly among devices and within a particular device. It is best to discuss the issue of battery life with the implant team.
Rechargeable batteries have to be replaced after one year of use. NiCad batteries cost substantially less than the lithium cell; however, lithium batteries recharge more quickly and hold greater power. Recharge time varies and can be as little as two hours for lithium batteries or as long as fourteen hours for NiCads. These, too, are issues to be reviewed by implant team members.
Children should carry a spare battery with them at all times. However, if the spare battery is not used for a long period of time, it will lose its charge and become nonfunctional. Also, when transporting batteries, it is best to cover the contact ends with tape or plastic; if the contact points are placed against anything metallic (such as loose change in a pocket or purse) the battery will discharge power.