Research Papers

Green laser light activates the inner ear

[+] Author Affiliations
Gentiana I. Wenzel

Medical University Hannover, Department of Otolaryngology, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany

Sven Balster

Medical University Hannover, Department of Otolaryngology, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany

Kaiyin Zhang

Laser Zentrum Hannover, Hollerithallee 8, Hannover, 30419, Germany

Hubert H. Lim, Uta Reich

Medical University Hannover, Department of Otolaryngology, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany

Ole Massow, Holger Lubatschowski

Laser Zentrum Hannover, Hollerithallee 8, Hannover, 30419, Germany

Wolfgang Ertmer

Leibniz University of Hannover, Institute of Quantum Optics, Welfengarten 1, Hannover, 30167, Germany

Thomas Lenarz, Guenter Reuter

Medical University Hannover, Department of Otolaryngology, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany

J. Biomed. Opt. 14(4), 044007 (July 20, 2009). doi:10.1117/1.3174389
History: Received February 06, 2009; Revised May 06, 2009; Accepted May 21, 2009; Published July 20, 2009
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The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices. Laser light can be focused in a controlled manner and may provide more localized activation of the inner ear, the cochlea. We sought to assess whether visible light with parameters that could induce an optoacoustic effect (532nm, 10-ns pulses) would activate the cochlea. Auditory brainstem responses (ABRs) were recorded preoperatively in anesthetized guinea pigs to confirm normal hearing. After opening the bulla, a 50-μm core-diameter optical fiber was positioned in the round window niche and directed toward the basilar membrane. Optically induced ABRs (OABRs), similar in shape to those of acoustic stimulation, were elicited with single pulses. The OABR peaks increased with energy level (0.6to23μJ/pulse) and remained consistent even after 30minutes of continuous stimulation at 13μJ, indicating minimal or no stimulation-induced damage within the cochlea. Our findings demonstrate that visible light can effectively and reliably activate the cochlea without any apparent damage. Further studies are in progress to investigate the frequency-specific nature and mechanism of green light cochlear activation.

Figures in this Article
© 2009 Society of Photo-Optical Instrumentation Engineers

Topics

Lasers ; Ear

Citation

Gentiana I. Wenzel ; Sven Balster ; Kaiyin Zhang ; Hubert H. Lim ; Uta Reich, et al.
"Green laser light activates the inner ear", J. Biomed. Opt. 14(4), 044007 (July 20, 2009). ; http://dx.doi.org/10.1117/1.3174389


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