不同脉宽条件下人工耳蜗植入者术中电诱发听性脑干反应检测的特点分析

Characteristics analysis of EABR detected during cochlear implantation under conditions of different pulse width

目的比较不同脉宽条件下人工耳蜗植入者术中电诱发听性脑干反应(electrically evoked auditory brainstem response,EABR)的特点,分析脉宽与EABR波V引出率和阈值之间的关系,总结不同脉宽条件对EABR波V引出率和阈值的影响,选择更优化的EABR脉宽测试参数。方法无残余听力的人工耳蜗植入患者24例作为实验组,其中耳蜗形态正常12例、大前庭导水管综合征(large vestibular aqueduct syndrome,LVAS)4例、Mondini畸形4例、共同腔畸形(common cavity deformation,CCD)2例、内听道狭窄2例;筛选条件相近的24例有残余听力的人工耳蜗植入者配对作为对照组。应用改装的Cochlear Freedom人工耳蜗及自制的铂铱合金球电极对拟行人工耳蜗植入的两组者术中分别给予50、100、200μs不同脉宽的电刺激,Bio-logic Navigator Pro听觉诱发电位仪记录不同脉宽条件下EABR波V引出率和阈值。结果脉宽50、100、200μs时,EABR波V引出率实验组(均为91.7%)低于对照组(分别为100%、100%、95.8%),差异无统计学意义(P均>0.05);而EABR阈值实验组[分别为(183.73±8.96)CL、(151.28±10.05)CL、(120.56±12.82)CL]高于对照组[分别为(175.50±9.14)CL、(142.71±11.45)CL、(110.63±10.24)CL],差异均具有统计学意义(t值分别为18.87、16.82、17.64,P均<0.05)。结论蜗内单极刺激能诱发出良好的EABR波形,无残余听力的患者EABR阈值要明显高于有残余听力的患者。相对于脉宽200μs,50、100μs时EABR波形波V引出率高;脉宽50μs波形分化更好、动态范围广,内耳畸形严重可能需要适当加大刺激量(如将脉宽改为100μs)。

Objective To compare the characteristics of intra-operative electrical evoked auditory brain stem response（EABR） under conditions of different pulse width, to analysis the relationships of pulse width with lead-out rate and threshold of EABR wave V, summarize the effect of pulse width on the lead-out rate and threshold, and to select optimized pulse width parameters of EABR. Methods A study was performed on 24 patients with no residual hearing （ 12 cases with normal cochlear, 4 with LVAS, 4 with Mondini deformation, 2 with common cavity deformation, and 2 with internal auditory canal stenosis ） （test group） matched with 24 implantees with residual hearing （control group）. With modified Freedom cochlear implant and ball-end platinum-iridium wire electrode, the two groups were given electrical stimulations of 50 μs, 100 Ixs and 200 μs pulse width, recording lead-out rate and threshold of EABR wave V under different pulse width with Biologic Navigator Pro-evoked potential instrument. Results EABR wave V lead-out rates of the test group （ 91.7 % ,91.7 % and 91.7% ） were lower than those of the control group （ 100%, 100% and 95.8 % ）, but their differences were all statistically insignificant （ all P 〉 0.05 ）. The thresholds of the test group （ 183.73 ± 8.96 CL, 151.28 ± 10.05 CL and 120. 56 ± 12. 82 CL） were higher than those of the control group （ 175.50 ± 9. 14 CL, 142.71 ± 11.45 CL, and 110. 63 ± 10.24 CL） and differences were statistically significant （all P 〈 0. 05）. Conclusions Intracochlear monopolar stimulation can induce good EABR waveform. Thresholds of EABR wave V in patients with no residual hearing are significantly higher than those in patients with residual hearing. EABR wave V lead-out rates under pulse width of 50 μs and 100 μs are higher than that under pulse width 200 μs. EABR waveform differentiation is the best under pulse width of 50 μs. The amount of stimulation need to be increased in severe deformity.