Frequency-specific activation of the peripheral auditory system using optoacoustic laser stimulation

Patricia Stahn,Hans-Jochen Foth,Gentiana I Wenzel,Achim Langenbucher,Lukas Pillong,Marc Kannengießer,Hubert H Lim,Cathleen Schreiter,Marius P Hinsberger,Katharina Sorg,Bernhard Schick

doi:10.1038/s41598-019-40860-8

Patricia Stahn, Hans-Jochen Foth + Show 9 more

Open Access

https://doi.org/10.1038/s41598-019-40860-8

Copy DOI

Journal: Scientific Reports	Publication Date: Mar 12, 2019
Citations: 9	License type: open-access

Affiliation: Saarland University, University of Minnesota

Abstract

Hearing impairment is one of the most common sensory deficits in humans. Hearing aids are helpful to patients but can have poor sound quality or transmission due to insufficient output or acoustic feedback, such as for high frequencies. Implantable devices partially overcome these issues but require surgery with limited locations for device attachment. Here, we investigate a new optoacoustic approach to vibrate the hearing organ with laser stimulation to improve frequency bandwidth, not requiring attachment to specific vibratory structures, and potentially reduce acoustic feedback. We developed a laser pulse modulation strategy and simulated its response at the umbo (1–10 kHz) based on a convolution-based model. We achieved frequency-specific activation in which non-contact laser stimulation of the umbo, as well as within the middle ear at the round window and otic capsule, induced precise shifts in the maximal vibratory response of the umbo and neural activation within the inferior colliculus of guinea pigs, corresponding to the targeted, modelled and then stimulated frequency. There was also no acoustic feedback detected from laser stimulation with our experimental setup. These findings open up the potential for using a convolution-based optoacoustic approach as a new type of laser hearing aid or middle ear implant.

Highlights

There are about 360 million individuals worldwide who struggle with hearing impairment and have difficulties in communicating on a daily basis[1]
Laser Doppler vibrometer (LDV) measurements at the central point of the ear drum in explanted specimens (Fig. 2a; see Methods) and neurophysiological recordings in the inferior colliculus (ICC) in anesthetized guinea pigs (Fig. 2b; see Methods) were collected in response to stimulation with these different laser patterns presented to the ear drum or middle ear structures
Denmark) near the ear canal opening and recorded sound signals generated from laser stimulation of the umbo and did not detect any acoustic feedback

Summary

Introduction

There are about 360 million individuals worldwide who struggle with hearing impairment and have difficulties in communicating on a daily basis[1]. This study seeks to answer that question through simulations and experiments in a guinea pig model to demonstrate that laser pulse stimulation of the ear drum and middle ear structures can achieve precise and predictable frequency-specific activation of the auditory system.

Results

Conclusion