[The objective method for recording stapedial reflex during surgery for cochlear implantation]

The purpose of the present study was to develop a method for the objective registration of the stapedial reflex at the contralateral ear during cochlear implantation surgery on the affected one. The excessive pressure in the middle ear (up to 500 daPa) was compensated by the administration of an additional air volume (1 liter) into the AA220 impedance meter pneumatic circuit. A syringe was used to measure variations of pressure in the new pneumatic circuit. Eight of the 12 patients demonstrated coincident visual and objective reflex thresholds. In the remaining 4 patients, the visually apparent stapedial reflex thresholds proved higher than those obtained objectively by the standard procedure of impedancemetry. It is concluded that the objective registration of the stapedial reflex excludes the effect of subjective factors interfering with its estimation and provides the possibility for comparative intra- and postoperative studies using one and the same instrument.