gms | German Medical Science

Postoperative stapedius reflex measurements are used by several research groups as objective method for the estimation of comfort levels in patients supplied with CI. In most cases, the fitting of the speech processor is directly based on reflex threshold (ESRT). The present study was performed in order to reduce the time needed for testing and to check, whether there exists a general trend of ESRT after some time of implant use.

ESRT was determined using a standardized testing procedure in children supplied with the COMBI40+ implant system. The automated test protocol, which was successfully applied for several years in our department, is based on acoustic impedance audiometry during electrical stimulation via the implant. Prior to single channel stimulation, as generally used for the fitting procedure, the patient was stimulated using a multichannel stimulation mode in order to check if ESRT testing could be done at the particular fitting session. Changes of ESRT over time were investigated at testing sessions in a period from about 40 days up to 5 years after implantation.

Results show that ESRT fluctuates most within the first 6 months of implant use. After this time, a trend towards a stable channel dependence typical for each patient is observed. In all patients, ESRT for multichannel stimulation was below the corresponding mean ESRT values of single channel stimulation.

The temporal development for both modes was similar. A general trend of ESRT for all patients was not observed.