20例Med-EL Combi 40+人工耳蜗术后电极阻抗和检测阈值及最大舒适阈值变化的观察

Observation on the change of electrode impedance and THR/MCL values in 20 cases with Med-EL Combi 40+ cochlear implant

目的:观察Med-EL Combi 40+人工耳蜗植入后电极阻抗、检测阈值(THR)、最大舒适阈(MCL)、动态范围的变化规律,分析其内在联系,探讨其对术后调机的指导意义。方法:回顾性分析连续的20例植入MedEL Combi 40+人工耳蜗患儿,对术中、术后1、3、6、12、24、36个月的电极阻抗值,以及对应时间点的THR、MCL值、动态范围进行分析,探讨其变化规律及相关性。结果:总体而言,各电极阻抗值术中检测最低,术后1个月时电阻较术中有明显升高(P<0.01),术后3个月时电阻略有下降(P<0.01),随后蜗顶组和中间组电极电阻基本趋于平稳,但蜗底的电极电阻呈逐年升高。各电极通道THR值基本随术后时间延长逐渐增高(P<0.05),MCL值术后早期呈显著上升(P<0.05),但第2年起趋于平稳。蜗底组电极的动态范围术后早期呈上升,但1年后出现下降趋势。各组电极电荷量术后3个月升高显著(P<0.05),术后1年起趋于稳定(P>0.05)。电极电阻与动态范围的相关性较THR值、MCL值高,且呈负相关。术后3个月、6个月时的电极电阻与术后3年时的动态范围呈强负相关,均以蜗顶组最明显(r=-0.618,r=-0.636,均P<0.01)。结论:电极电阻的变化规律会因电极的位置不同而异,测定电极阻抗值能有效评估人工耳蜗刺激电极状态;术后电极THR、MCL值与电极电阻的关联性小,可能受众多因素影响所致,但电极的动态范围与电阻呈负相关;术后3个月或6个月时的电极电阻具有预测动态范围大小的意义。

Objective： To investigate the changes of electrode impedance, THR/MCL values, and dynamic range（DR） in Combi 40＋ cochlear implant after implantation. Method： A respective study was carried out collec- ting 20 consecutively implanted childrenrs electrode impedances, THR/MCL values, and DR at seven time point during the first three years after implantation. Their variation and correlations were analyzed. Result：Overall, elec- trode impedances were lowest during the operation, and significantly rise to the highest at the first stimulation,then followed hy a gradual ＆＇crease. After three nlonlhs, electrode iml^edance of apical and medial cochlear seg merit were basically stable, while that of the basal segment was gradually increased. Dynamlic range（DR） of apical and medial group electrode increased early after the operation and showed a stahilization from the second year. whereas that of basal group have a downward trend since the first year. However, the electric charge of each grcmp incre＇asect significantly after three months, and then heeonae stable after first year. Otherwise. a stronger negative rectilinear correlation was found between impedance changes with I）R than with THR/MCI, Level. Conclu- sion：The electrode italic＇dances vary due to different electrode posilion. Measuring the electrode impedance can effi cientively evaluate the working status Of Combi C.10 ＋ cochlear implant. The dynamic range of the electrode was negatively correlated ＇,,villa the impeclanees, which made it possible to predict the width of the dynamic range by measuring the impedance 3 or 6 monlhs afier operalion.