Optoacoustically induced auditory brainstem responses in the mouse model enhanced through an absorbing film

Abstract

. Significance: Optoacoustic stimulation offers an alternative stimulation strategy for the hearing organ. To serve as the base for a novel auditory prosthesis, the optoacoustic stimulation must be biocompatible and energy-saving. Aim: Enhancing the efficiency of optoacoustic stimulation while reducing the energy input in a suited animal model. Approach: Optoacoustically induced auditory brainstem responses (oABRs) were recorded after the pulsed laser irradiation of the tympanic membrane (TM) in mice. The results were compared with the ABRs induced through acoustic click stimulation. In addition, self-adhesive absorbing films were applied on the TM before the optoacoustic stimulation to investigate their effect on the resulting ABRs. Results: Using an absorbing film on the TM during optical stimulation led to considerably enhanced oABR wave I amplitude values compared with the stimulation of the bare TM. When using our stimulation strategy, we induced oABR waves in the 50% to 60% range of the acoustical stimulation reached with 80-dB SPL click stimuli. Conclusions: The mouse model can be used for certain developmental work for an optoacoustic auditory prosthesis. Using absorbing films on the TM during optical stimulation considerably enhances oABR wave I amplitude. Optimization of the stimulation strategy could further enhance the efficiency within biocompatibility margins.

Feasibility evaluation of transtympanic laser stimulation of the cochlea from the outer ear

“…The tympanic membrane on the glass slide was irradiated using the pulsed laser (duration, 100 µs; repetition rate, 4,000 Hz) at 10.1 mJ/cm 2 . The original radiant energy (I0) and transmitted energy of the tympanic membrane (I) was recorded to calculate the absorbance (A) as previously described (Goblet et al, 2021;Sorg et al, 2021) using the following equation:…”