Change and Application of Electrode Impedances and Electrically-evoked Compound Action Potentials after Cochlear Implantation

[Objective] To observe the change of the electrode impedances and the thresholds of the electrically-evoked compound action potentials in different time points after cochlear implantation and to help for deciding the interval of the mapping.[Methods] To test the electrode impedances and electrically-evoked compound action potentials of 17 cases who had accepted the cochlear implantation in different time points:intra-operation,initial stimulation in 30 days after operation,and 10,20,30,40,50,60,90,150 days after initial stimulation.[Results] Compared with the other time points,the electrode impedances were the lowest at intra-operation and the highest at initial stimulation,with statistical significance;There were significant differences in the electrode impedances between the 22nd electrode and the 2nd,4th,6th,8th,10th,12th electrodes in different time points.There were significant differences in the ECAP thresholds of the 2nd,4th,6th,8th,10th,12th electrodes between intra-operation and initial stimulation.[Conclusion] The impedance had a rapid decrease after initial stimulation,and got the lowest level 10 days later after initial stimulation;but the distinct change of ECAP threshold could not be found;If the electrode impedance and ECAP threshold had tended to maintain stable in two months after initial stimulation,mapping could be postponed according the performance of the patients.