목적: Research indicates that increasing the number of cochlear implant channels enhances auditory performance, improves sound quality perception, and reduces the cognitive effort required for sound recognition, leading to a more comfortable auditory experience. To evaluate the performance and biocompatibility of a newly developed 32- channel cochlear implant, we implanted the device in a minipig model. We measured the Electrically Evoked Auditory Brainstem Response (EABR) to verify functionality and predict auditory performance. Additionally, histological analysis is being conducted to assess tissue response and biocompatibility. This study aims to comprehensively evaluate the properties of the 32-channel system. 방법:The cochlear implant channels, ranging from 16 to 26, were inserted using the round window approach, with the internal device coil and body placed at the apex of the minipig's head. EABR measurements were conducted over a three-month period following implantation, at intervals of approximately two weeks to one month. For these measurements, the external device was attached to the head. The measurement parameters included a pulse rate of 40 Hz, pulse widths of 25 and 50 µs/ph, and pulse amplitude levels ranging from 0 to 255 current levels. After EABR measurements, the cochlea was explanted, and Hematoxylin and Eosin (H&E) staining was performed to examine spiral ganglion neurons. Additionally, epoxy embedding was conducted to analyze the electrode's position within the cochlea and assess any potential traumatic response. 결과:After the cochlear implant, we measured the EABR to observe how the response amplitude changed with stimulation pulse width, current level (CL), and over time. The EABR Amplitude was 1.78 times larger when stimulus pulse width increased from 25 µs/pulse to 50 µs/pulse(p<0.001) 0.738 ± 0.498 µA and 1.314 ± 1.26 µA. Inversely, the EABR Threshold was 1.615 times larger when stimulus pulse width increased from 25 µs/pulse to 50 µs/pulse (p<0.004): 822 ± 178 µA and 509 ± 105 µA. The input-output growth was fitted into a sigmoid exponential function (amplitude=max/(1+exp(-k*(CL-CL0)))). The slope(CL0) of this exponential function was significantly greater in channel15 compared to that of channel1 which deeper electrode channel in the cochlear. The maximum value (max) of EABR gradually increased with time during the first two months after implantation (p= 0.00015)0.552±0.377 µV on 1st, and 1.080± 0.647 on 2nd month, (pulse width 25us/ph), (p= 0.0095)0.988±0.58 µV on 1st, and 1.588± 1.121 on 2nd month, (pulse width 50us/ph). 결론:Our study on the 32-channel cochlear implant system in minipigs remains ongoing, with key observations highlighting the relationship between stimulation parameters and auditory response. Specifically, we found that EABR amplitude increased with a wider stimulus pulse width and prolonged implantation time, particularly within the first two months Notably, the growth pattern of EABR amplitude was more pronounced in the electrodes positioned deeper within the cochlea compared to those located more peripherally. Given their anatomical resemblance to the human cochlea, minipigs are more clinically relevant models than rodents, enabling a more accurate translation of findings to human applications. These results provide valuable insights into the electrophysiological behavior of the cochlea in response to artificial current stimulation, further informing cochlear implant optimization and potential improvements in auditory prostheses.