Tian Guan,Kai Zhu Graduate School at Shenzhen, Tsinghua Univ. (China) Jian Wang Shenzhen Institute of Information Technology (China) Fei Chen South Univ. of Science and Technology of China (China) Yonghong He,Mocun Wu Graduate School at Shenzhen, Tsinghua Univ. (China) Guohui Nie Peking Univ. Shenzhen Hospital (China)
The discovery that a pulsed laser could trigger an auditory neural response inspired ongoing research on cochlear implants activated by optical stimulus rather than by electrical current. However, most studies to date have used visible light (532 nm) or long-wavelength near-infrared (<1840 nm) and involved making a hole in the cochlea. This paper investigates the effect of optical parameters on the optically evoked compound action potentials (oCAPs) from the guinea pig cochlea, using a pulsed semiconductor near-infrared laser (980 nm) without making a hole in the cochlea. Synchronous trigger laser pulses were used to stimulate the cochlea, before and after deafening, upon varying the pulse duration (30–1000 μs) and an amount of radiant energy (0–53.2 mJ/cm2). oCAPs were successfully recorded after deafening. The amplitude of the oCAPs increased as the infrared radiant energy was increased at a fixed 50 μs pulse duration, and decreased with a longer pulse duration at a fixed 37.1 mJ/cm2 radiant energy. The latency of the oCAPs shortened with increasing radiant energy at a fixed pulse duration. With a higher stimulation rate, the amplitude of the oCAPs’ amplitude decreased.