[Detection of the electric brain stem auditory response before cochlear implantation and its significance]

Objective: Analysis of the outcome of the electric brain stem auditory response (EABR) before cochlear implantation (CI) and the mapping parameters after CI in 187 cases, to explore the significance of EABR before CI. Methods: From February, 2008 to December, 2014, EABR were performed in 187 patients with normal cochlear structures before CI with Nucleus 24R multi-channel cochlear. Including 105 cases of male, 82 cases of female; 152 cases of no residual hearing, 35 cases of residual hearing. Self-design electrical stimulator and US Bio-logic auditory evoked potential were taken, EABR were performed under general anesthesia before CI, recording EABR waveforms, measuring the latency of Ⅱ, Ⅲ, Ⅳ, Ⅴ wave and the Ⅲ-Ⅴ interval, Ⅴ-wave amplitude, Ⅴ-wave threshold and I/O curve slope. Data were analysis by SPSS19.0. Results: EABR waveforms were recorded in all 187 patients. The Ⅱ, Ⅲ, Ⅳ, Ⅴ waves are similar with the acoustic evoked ABR, the waveforms differentiation were different in ages, but no significant difference in gender. At 50 μs pulse electrical stimulation, the average threshold of V-wave was (156.37±21.44)CL, the average dynamic range was (36.33±8.63)CL. 20 CL above the threshold, average latency of wave Ⅱ, Ⅲ, Ⅴ was (1.54±0.12)ms, (2.06±0.23)ms and (4.14±0.25)ms, the Ⅲ-Ⅴ interval was (2.08±0.24)ms, the average amplitude of Ⅴ-wave was (0.35±0.07)μV. One month later, the 187 patients achieved different degrees of hearing, the average C value of mapping was (163.55±27.43)CL, significantly correlated with EABR threshold(r=0.915, P=0.013). The EABR threshold in 35 cases of no residual hearing value was (163.82±16.21)CL and Ⅴ-wave I/O curve slope was 0.035 227±0.013 918, and the threshold was (148.41±15.38)CL , the slope was 0.041 364±0.013 623 in paired group of 35 residual hearing patients, there was a statistically significant difference between two groups(t=15.838 and 4.328, P<0.05). Conclusions: The EABR detection method is reliable, extraction rate is high. EABR can be used to evaluate the auditory pathway before inserting electrode, which could provide the help for the screening operative indications of CI.