小儿人工耳蜗植入后神经反应成像的分析

An Analysis of the Neural Response Imaging Study of Children with Cochlear Implants

目的分析儿童人工耳蜗植入者电极在耳蜗不同部位的神经反应成像（neuraIresponseimaging，NRI）特点，以及开机后第一年NRI的变化。方法研究对象为29例5岁以下单侧植入HiResoIutionBioniCEar系列人工耳蜗的儿童。应用SoundWave软件记录每位植入者第3、7、11、15号的NRI阈值（NRIthreshoId，tNRI）以及NRI幅值增长线性拟合的斜率。根据耳蜗位x线平片确认植入电极在耳蜗内的位置。比较不同位置电极的tNRI及NRI幅值增长斜率的差异，并分析其在开机时及开机后3、6、12个月的变化。结果单因素方差分析显示，与耳蜗底转电极相比，耳蜗中转电极的tNRl较低，NRI幅值增长斜率较高，其差异均有统计学意义（P〈0．05）。经配对f检验分析，开机1年内不同测试时间各电极tNRI和NRI幅值增长斜率均无明显变化。结论耳蜗不同位置电极的NRI存在差异：越靠近耳蜗中转，tNRI越低，NRI幅值增长斜率越高，这与刺激电极对应的蜗内神经组织分布有关，越靠近耳蜗中转神经纤维密度越高，存活的神经组织越多。开机第一年，耳蜗各区域的tNRI和NRI幅值增长斜率无明显变化，提示该期间电刺激对耳蜗神经功能并无明显影响。

Objective To analyze the characteristics of neural response imaging （NRI） at different sites of cochleae in children with CIs and to find out the changes of NRI one year after switch-on. Methods Twenty-nine children with unilateral HiResolution Bionic Ear CI younger than 5 years old were involved in this study. The SoundWave software was used to record the NRI thresholds （tNRI） of electrode 3,7,11 and 15 and the slope of the amplitude growth curve for each patient. The locations of the electrodes were determined by plain X-ray. The differences of tNRI and slope of amplitude growth curve at different locations were compared and the changes at the time of switch-on and 3, 6, and 12 months after switch-on were analyzed. Results One- way analysis of variance showed that the electrodes of mid-cochlear turn had lower tNRIs and higher slopes of amplitude growth curve than those at cochlear base and the differences were statistically significant（P〈0.05）. The paired T-test indicated that there was no obvious change in tNRIs and slopes of amplitude growth curve at different time points within one year after switch- on. Conclusion There were significant differences in NRIs between different sites of cochlea. The nearer the electrodes to the middle turn, the lower the tNRI and the higher the slope of NRI amplitude growth curve. These differences may be related to the locations of neural tissue in the cochlea, since the density of nerve fibers and survival rate of neural tissues were higher in the middle turn. At different periods of the first year of CI use, there was no significant difference in tNRI and NRI amplitude growth curve slope, which indicates the electronic stimulations have no remarkable effects on the function of cochlear nerves during this period.