Infrared laser stimulation has been studied as an alternative approach to auditory prostheses. This study evaluated the feasibility of infrared laser stimulation of the cochlea from the outer ear, bypassing the middle ear function. An optic fiber was inserted into the ear canal, and a laser was used to irradiate the cochlea through the tympanic membrane in Mongolian gerbils. A pulsed infrared laser (6.9 mJ/cm2) and clicking sound (70 peak-to-peak equivalent sound pressure level) were presented to the animals. The amplitude of the laser-evoked cochlear response was systematically decreased following insertion of a filter between the tympanic membrane and cochlea; however, the auditory-evoked cochlear response did not decrease. The filter was removed, and the laser-evoked response returned to around the original level. The amplitude ratio and the relative change in response amplitude before and during filter insertion significantly decreased as the absorbance of the infrared filter increased. These results indicate that laser irradiation could bypass the function of the middle ear and directly activate the cochlea. Therefore, laser irradiation from the outer ear is a possible alternative for stimulating the cochlea, circumventing the middle ear.

1.
Ahmed
,
J.
,
Saqulain
,
G.
,
Khan
,
M. I. J.
, and
Kausar
,
M.
(
2021
). “
Complications of cochlear implant surgery: A public implant centre experience
,”
Pak. J. Med. Sci.
37
,
1519
1523
.
2.
Baumhoff
,
P.
,
Kallweit
,
N.
, and
Kral
,
A.
(
2019
). “
Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in vivo
,”
Hear. Res.
371
,
40
52
.
3.
Fekete
,
Z.
,
Horváth
,
Á. C.
, and
Zátonyi
,
A.
(
2020
). “
Infrared neuromodulation: A neuroengineering perspective
,”
J. Neural Eng.
17
,
051003
.
4.
Fridberger
,
A.
, and
Ren
,
T.
(
2006
). “
Local mechanical stimulation of the hearing organ by laser irradiation
,”
Neuroreport
17
,
33
37
.
5.
Goblet
,
M.
,
Matin
,
F.
,
Lenarz
,
T.
, and
Paasche
,
G.
(
2021
). “
Optical absorbance of the tympanic membrane in rat and human samples
,”
PLoS One
16
,
e0254902
.
6.
Goyal
,
V.
,
Rajguru
,
S.
,
Matic
,
A. I.
,
Stock
,
S. R.
, and
Richter
,
C. P.
(
2012
). “
Acute damage threshold for infrared neural stimulation of the cochlea: Functional and histological evaluation
,”
Anat. Rec.
295
,
1987
1999
.
7.
Grosh
,
K.
,
Ren
,
T.
,
He
,
W.
,
Fridberger
,
A.
,
Li
,
Y.
, and
Nankali
,
A.
(
2015
). “
Light-induced basilar membrane vibrations in the sensitive cochlea
,”
AIP Conf. Proc.
1703
,
070005
.
8.
Håkansson
,
B.
,
Eeg-Olofsson
,
M.
,
Reinfeldt
,
S.
,
Stenfelt
,
S.
, and
Granström
,
G.
(
2008
). “
Percutaneous versus transcutaneous bone conduction implant system: A feasibility study on a cadaver head
,”
Otol. Neurotol.
29
,
1132
1139
.
9.
Heimann
,
L.
,
Carlein
,
C.
,
Sorg
,
K.
,
Diller
,
R.
,
Langenbucher
,
A.
,
Schick
,
B.
, and
Wenzel
,
G. I.
(
2021
). “
Wavelength-specific optoacoustic-induced vibrations of the guinea pig tympanic membrane
,”
J. Biomed. Opt.
26
,
038001
.
10.
Izzo
,
A. D.
,
Richter
,
C. P.
,
Jansen
,
E. D.
, and
Walsh
,
J. T.
, Jr.
(
2006
). “
Laser stimulation of the auditory nerve
,”
Lasers Surg. Med.
38
,
745
753
.
11.
Izzo
,
A. D.
,
Walsh
,
J. T.
, Jr.
,
Jansen
,
E. D.
,
Bendett
,
M.
,
Webb
,
J.
,
Ralph
,
H.
, and
Richter
,
C. P.
(
2007
). “
Optical parameter variability in laser nerve stimulation: A study of pulse duration, repetition rate, and wavelength
,”
IEEE Trans. Biomed. Eng.
54
,
1108
1114
.
12.
Lim
,
D. J.
(
1970
). “
Human tympanic membrane. An ultrastructural observation
,”
Acta Otolaryngol.
70
,
176
186
.
13.
Littlefield
,
P. D.
, and
Richter
,
C. P.
(
2021
). “
Near-infrared stimulation of the auditory nerve: A decade of progress toward an optical cochlear implant
,”
Laryngoscope Investig. Otolaryngol.
6
,
310
319
.
14.
Matic
,
A. I.
,
Robinson
,
A. M.
,
Young
,
H. K.
,
Badofsky
,
B.
,
Rajguru
,
S. M.
,
Stock
,
S.
, and
Richter
,
C. P.
(
2013
). “
Behavioral and electrophysiological responses evoked by chronic infrared neural stimulation of the cochlea
,”
PLoS One
8
,
e58189
.
15.
Pillong
,
L.
,
Stahn
,
P.
,
Hinsberger
,
M.
,
Sorg
,
K.
,
Schick
,
B.
, and
Wenzel
,
G. I.
(
2020
). “
Cytotoxicity studies of an optoacoustic stimulation strategy for the development of laser-based hearing aids
,”
J. Biomed. Opt.
25
,
068002
.
16.
Rajguru
,
S. M.
,
Matic
,
A. I.
,
Robinson
,
A. M.
,
Fishman
,
A. J.
,
Moreno
,
L. E.
,
Bradley
,
A.
,
Vujanovic
,
I.
,
Breen
,
J.
,
Wells
,
J. D.
,
Bendett
,
M.
, and
Richter
,
C. P.
(
2010
). “
Optical cochlear implants: Evaluation of surgical approach and laser parameters in cats
,”
Hear. Res.
269
,
102
111
.
17.
Ren
,
T.
,
He
,
W.
,
Li
,
Y.
,
Grosh
,
K.
, and
Fridberger
,
A.
(
2014
). “
Light-induced vibration in the hearing organ
,”
Sci. Rep.
4
,
5941
.
18.
Richter
,
C. P.
,
Bayon
,
R.
,
Izzo
,
A. D.
,
Otting
,
M.
,
Suh
,
E.
,
Goyal
,
S.
,
Hotaling
,
J.
, and
Walsh
,
J. T.
, Jr.
(
2008
). “
Optical stimulation of auditory neurons: Effects of acute and chronic deafening
,”
Hear. Res.
242
,
42
51
.
19.
Schmid
,
B.
,
Schindelin
,
J.
,
Cardona
,
A.
,
Longair
,
M.
, and
Heisenberg
,
M.
(
2010
). “
A high-level 3D visualization API for Java and ImageJ
,”
BMC Bioinformatics
11
,
274
.
20.
Schultz
,
M.
,
Baumhoff
,
P.
,
Maier
,
H.
,
Teudt
,
I. U.
,
Krüger
,
A.
,
Lenarz
,
T.
, and
Kral
,
A.
(
2012
). “
Nanosecond laser pulse stimulation of the inner ear-a wavelength study
,”
Biomed. Opt. Express
3
,
3332
3345
.
21.
Sordillo
,
L. A.
,
Pu
,
Y.
,
Pratavieira
,
S.
,
Budansky
,
Y.
, and
Alfano
,
R. R.
(
2014
). “
Deep optical imaging of tissue using the second and third near-infrared spectral windows
,”
J. Biomed. Opt.
19
,
056004
.
22.
Sorg
,
K.
,
Heimann
,
L.
,
Lana
,
G. M.
,
Langenbucher
,
A.
,
Schick
,
B.
,
Arzt
,
E.
, and
Wenzel
,
G. I.
(
2021
). “
Optoacoustically induced auditory brainstem responses in the mouse model enhanced through an absorbing film
,”
J. Biomed. Opt.
26
,
098001
.
23.
Sorg
,
K.
,
Stahn
,
P.
,
Pillong
,
L.
,
Hinsberger
,
M. P.
,
Heimann
,
L.
,
Foth
,
H. J.
,
Schick
,
B.
, and
Wenzel
,
G. I.
(
2019
). “
First biocompatibility margins for optical stimulation at the eardrum via 532-nm laser pulses in a mouse model
,”
J. Biomed. Opt.
24
,
085003
.
24.
Tamai
,
Y.
,
Horinouchi
,
K.
,
Hiryu
,
S.
, and
Kobayasi
,
K. I.
(
2019
). “
Infrared laser stimulation of cochlear nerve through a tympanic membrane
,” in
Proceedings of the 2019 IEEE 1st Global Conference on Life Sciences and Technologies (LifeTech)
, March 12–14, Osaka, Japan, pp.
54
57
.
25.
Tamai
,
Y.
,
Ito
,
Y.
,
Furuyama
,
T.
,
Horinouchi
,
K.
,
Murashima
,
N.
,
Michimoto
,
I.
,
Hishida
,
R.
,
Shibuki
,
K.
,
Hiryu
,
S.
, and
Kobayasi
,
K. I.
(
2020
). “
Auditory cortical activity elicited by infrared laser irradiation from the outer ear in Mongolian gerbils
,”
PLoS One
15
,
e0240227
.
26.
Tan
,
X.
,
Jahan
,
I.
,
Xu
,
Y.
,
Stock
,
S.
,
Kwan
,
C. C.
,
Soriano
,
C.
,
Xiao
,
X.
,
Garcia-Añoveros
,
J.
,
Fritzsch
,
B.
, and
Richter
,
C. P.
(
2018
). “
Auditory neural activity in congenitally deaf mice induced by infrared neural stimulation
,”
Sci. Rep.
8
,
388
.
27.
Teudt
,
I. U.
,
Maier
,
H.
,
Richter
,
C. P.
, and
Kral
,
A.
(
2011
). “
Acoustic events and ‘optophonic’ cochlear responses induced by pulsed near-infrared laser
,”
IEEE Trans. Biomed. Eng.
58
,
1648
1655
.
28.
Teudt
,
I. U.
,
Nevel
,
A. E.
,
Izzo
,
A. D.
,
Walsh
,
J. T.
, Jr.
, and
Richter
,
C. P.
(
2007
). “
Optical stimulation of the facial nerve: A new monitoring technique?
Laryngoscope
117
,
1641
1647
.
29.
Thompson
,
A. C.
,
Fallon
,
J. B.
,
Wise
,
A. K.
,
Wade
,
S. A.
,
Shepherd
,
R. K.
, and
Stoddart
,
P. R.
(
2015
). “
Infrared neural stimulation fails to evoke neural activity in the deaf guinea pig cochlea
,”
Hear. Res.
324
,
46
53
.
30.
von Unge
,
M.
,
Bagger-Sjöbäck
,
D.
, and
Borg
,
E.
(
1991
). “
Mechanoacoustic properties of the tympanic membrane: A study on isolated Mongolian gerbil temporal bones
,”
Am. J. Otol.
12
,
407
419
, available at https://europepmc.org/article/med/1805631.
31.
World Health Organization
(
2018
). “
Addressing the rising prevalence of hearing loss
,” https://apps.who.int/iris/handle/10665/260336 (Last viewed September 17, 2022).
32.
Xu
,
Y.
,
Xia
,
N.
,
Lim
,
M.
,
Tan
,
X.
,
Tran
,
M. H.
,
Boulger
,
E.
,
Peng
,
F.
,
Young
,
H.
,
Rau
,
C.
,
Rack
,
A.
, and
Richter
,
C. P.
(
2018
). “
Multichannel optrodes for photonic stimulation
,”
Neurophoton.
5
,
045002
.
33.
Yeung
,
J.
,
Griffin
,
A.
,
Newton
,
S.
,
Kenna
,
M.
, and
Licameli
,
G. R.
(
2018
). “
Revision cochlear implant surgery in children: Surgical and audiological outcomes
,”
Laryngoscope
128
,
2619
2624
.
34.
Young
,
H. K.
,
Tan
,
X.
,
Xia
,
N.
, and
Richter
,
C. P.
(
2015
). “
Target structures for cochlear infrared neural stimulation
,”
Neurophoton
2
,
025002
.
You do not currently have access to this content.