gms | German Medical Science

The use of objective measures in cochlear implanted patients is mainly dedicated to very young children and subjects who cannot cooperate (during surgery, for instance) or do not want to cooperate (very active children…). But it can also be very useful to assess the quality control of CI fitting. The clinician needs to have objective information about some parameters of the fitting to improve it and/or to get medico-legal arguments. Two main parameters are used in MAPS, although one (T) is not suggested by all the companies to fit the implants: Perception threshold level (T) and Comfort threshold level (C). Electrophysiology is a good tool to assess both parameters. NRT and EABR show correlations between T and objective threshold, although interindividual variability has been described. However, in one patient, the relationship between the NRT-T and the T level seems constant according to time. It is harder to find a good objective tool to assess the Comfort level as the determination of the C value suffers variability among teams and patients. However, NRT-T is somewhere between T and C values and the input-ouput function of EABRs could inform on the C value. Confrontation between objective measures and MAP improves the quality control of the fitting.