Acoustic stimulation of the human round window by laser-induced nonlinear optoacoustics

Acoustic stimulation of the human round window by laser-induced nonlinear optoacoustics

The feasibility of low frequency pure tone generation in the inner ear by laser-induced nonlinear optoacoustic effect at the round window was demonstrated in three human cadaveric temporal bones (TB) using an integral pulse density modulation (IPDM). Nanosecond laser pulses with a wavelength in the...

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Bibliographic Details
Published in:Scientific reports Vol. 14; no. 1; p. 8214
Main Authors: Lengert, Liza, Tomanek, Michael, Ghoncheh, Mohammad, Lohmann, Hinnerk, Prenzler, Nils, Kalies, Stefan, Johannsmeier, Sonja, Ripken, Tammo, Heisterkamp, Alexander, Maier, Hannes
Format: Journal Article
Language:English
Published: London Nature Publishing Group UK 08-04-2024
Nature Publishing Group
Nature Portfolio
Subjects:
631/378/2619/1592
639/624/1111/1115
Acoustic Stimulation
Acoustics
Active middle ear implant
Cadavers
Cochlea
Cochlea - physiology
Electro-acoustic stimulation
Humanities and Social Sciences
Humans
Inner ear
Lasers
multidisciplinary
Optoacoustic
Round Window, Ear - physiology
Scala Tympani - physiology
Science
Science (multidisciplinary)
Sound
Sound pressure
Optoacoustic
Active middle ear implant
Electro-acoustic stimulation
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Summary:The feasibility of low frequency pure tone generation in the inner ear by laser-induced nonlinear optoacoustic effect at the round window was demonstrated in three human cadaveric temporal bones (TB) using an integral pulse density modulation (IPDM). Nanosecond laser pulses with a wavelength in the near-infrared (NIR) region were delivered to the round window niche by an optical fiber with two spherical lenses glued to the end and a viscous gel at the site of the laser focus. Using IPDM, acoustic tones with frequencies between 20 Hz and 1 kHz were generated in the inner ear. The sound pressures in scala tympani and vestibuli were recorded and the intracochlear pressure difference (ICPD) was used to calculate the equivalent sound pressure level (eq. dB SPL) as an equivalent for perceived loudness. The results demonstrate that the optoacoustic effect produced sound pressure levels ranging from 140 eq. dB SPL at low frequencies ≤ 200 Hz to 90 eq. dB SPL at 1 kHz. Therefore, the produced sound pressure level is potentially sufficient for patients requiring acoustic low frequency stimulation. Hence, the presented method offers a potentially viable solution in the future to provide the acoustic stimulus component in combined electro-acoustic stimulation with a cochlear implant.
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ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-024-58129-0