TY - JOUR
T1 - Acoustic events and "optophonic" cochlear responses induced by pulsed near-infrared LASER
AU - Teudt, Ingo Ulrik
AU - Maier, Hannes
AU - Richter, Claus Peter
AU - Kral, Andrej
N1 - Funding Information:
Manuscript received September 7, 2010; revised November 12, 2010 and December 30, 2010; accepted January 4, 2011. Date of publication January 28, 2011; date of current version May 18, 2011. The work of C.-P. Richter was funded by the Federal funds from the National Institute of Deafness and Other Communication Disorders, Department of Health and Human Services, National Institutes of Health (NIH) under Contract HHSN260-2006-00006-C/Contract NIH N01-DC-6-0006. The work of I. Teudt and A. Kral was supported by Deutsche Forschungsgemeinschaft (SFB Transregio 37 Project A5). Pilot experiments for this study were performed in A. Kral’s laboratory at the Institute of Neurophysiology, University Clinics Hamburg-Eppendorf before moving the laboratory to Hannover. Asterisk indicates corresponding author. *I. U. Teudt is with the Institute of Audioneurotechnology and the Department of Experimental Otology ENT-Clinics, Hannover School of Medicine, 30625 Hannover, Germany (e-mail: teudt.ingo@mh-hannover.de).
PY - 2011/6
Y1 - 2011/6
N2 - Optical stimulation of neural tissue within the cochlea was described as a possible alternative to electrical stimulation. Most optical stimulation was performed with pulsed lasers operating with near-infrared (NIR) light and in thermal confinement. Under these conditions, the coexistence of laser-induced optoacoustic stimulation of the cochlea ("optophony") has not been analyzed yet. This study demonstrates that pulsed 1850-nm laser light used for neural stimulation also results in sound pressure levels up to 62dB peak-to-peak equivalent sound pressure level (SPL) in air. The sound field was confined to a small volume along the laser beam. In dry nitrogen, laser-induced acoustic events disappeared. Hydrophone measurements demonstrated pressure waves for laser fibers immersed in water. In hearing rats, laser-evoked signals were recorded from the cochlea without targeting neural tissue. The signals showed a two-domain response differing in amplitude and latency functions, as well as sensitivity to white-noise masking. The first component had characteristics of a cochlear microphonic potential, and the second component was characteristic for a compound action potential. The present data demonstrate that laser-evoked acoustic events can stimulate a hearing cochlea. Whenever optical stimulation is used, care must be taken to distinguish between such "optophony" and the true optoneural response.
AB - Optical stimulation of neural tissue within the cochlea was described as a possible alternative to electrical stimulation. Most optical stimulation was performed with pulsed lasers operating with near-infrared (NIR) light and in thermal confinement. Under these conditions, the coexistence of laser-induced optoacoustic stimulation of the cochlea ("optophony") has not been analyzed yet. This study demonstrates that pulsed 1850-nm laser light used for neural stimulation also results in sound pressure levels up to 62dB peak-to-peak equivalent sound pressure level (SPL) in air. The sound field was confined to a small volume along the laser beam. In dry nitrogen, laser-induced acoustic events disappeared. Hydrophone measurements demonstrated pressure waves for laser fibers immersed in water. In hearing rats, laser-evoked signals were recorded from the cochlea without targeting neural tissue. The signals showed a two-domain response differing in amplitude and latency functions, as well as sensitivity to white-noise masking. The first component had characteristics of a cochlear microphonic potential, and the second component was characteristic for a compound action potential. The present data demonstrate that laser-evoked acoustic events can stimulate a hearing cochlea. Whenever optical stimulation is used, care must be taken to distinguish between such "optophony" and the true optoneural response.
KW - Auditory system
KW - hearing aids
KW - infrared-radiation effects
KW - optical-radiation effects
KW - photoacoustic effects
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U2 - 10.1109/TBME.2011.2108297
DO - 10.1109/TBME.2011.2108297
M3 - Article
C2 - 21278011
AN - SCOPUS:79956359556
VL - 58
SP - 1648
EP - 1655
JO - IRE transactions on medical electronics
JF - IRE transactions on medical electronics
SN - 0018-9294
IS - 6
M1 - 5701771
ER -