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Schoovaerts M, Ourak M, Borghesan G, Putzeys T, Poorten EV, Verhaert N. OCT-based intra-cochlear imaging and 3D reconstruction: ex vivo validation of a robotic platform. Int J Comput Assist Radiol Surg 2024:10.1007/s11548-024-03081-7. [PMID: 38436923 DOI: 10.1007/s11548-024-03081-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 02/15/2024] [Indexed: 03/05/2024]
Abstract
PURPOSE The small size of the cochlea, and its location deeply embedded in thick temporal bone, poses a challenge for intra-cochlear guidance and diagnostics. Current radiological imaging techniques are not able to visualize the cochlear microstructures in detail. Rotational optical coherence tomography (OCT) fibers show great potential for intra-cochlear guidance. The generated images could be used to map, and study, the tiny cochlear microstructures relevant for hearing. METHODS This work describes the design of a rotational OCT probe with an outer diameter of 0.9 mm. It further discusses a robotic system, which features a remote center of motion mechanism, dedicated to the probe's positioning, fine manipulation and stable insertion into the cochlear micro-spaces. Furthermore, the necessary calibration steps for 3D reconstruction are described, followed by a detailed quantitative analysis, comparing the 3D reconstructions using a synthetic, 2:1 scaled scala tympani model with a reconstruction from micro-CT, serving as the ground truth. Finally, the potential of the system is demonstrated by scanning a single ex vivo cadaveric human cochlea. RESULTS The study investigates five insertions in the same 2:1 scaled tympani model, along with their corresponding 3D reconstruction. The comparison with micro-CT results in an average root-mean-square error of 74.2 µm, a signed distance error of 38.1 µm and a standard deviation of 63.6 µm. The average F-score of the reconstructions, using a distance threshold of 100 and 74.2 µm, resulted in 83.0% and 71.8%, respectively. Insertion in the cadaveric human cochlea showed the challenges for straight insertion, i.e., navigating the hook region. CONCLUSION Overall, the system shows great potential for intra-cochlear guidance and diagnostics, due to the system's capability for precise and stable insertion into the basal turn in the scala tympani. The system, combined with the calibration procedure, results in detailed and precise 3D reconstructions.
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Affiliation(s)
- Maarten Schoovaerts
- Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300, 3001, Leuven, Belgium.
- Department of Neurosciences, KU Leuven, Herestraat 49, 3001, Leuven, Belgium.
| | - Mouloud Ourak
- Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300, 3001, Leuven, Belgium
| | - Gianni Borghesan
- Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300, 3001, Leuven, Belgium
- Flanders Make, KU Leuven, Celestijnenlaan 300, 3001, Leuven, Belgium
| | - Tristan Putzeys
- Department of Neurosciences, KU Leuven, Herestraat 49, 3001, Leuven, Belgium
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200, 3001, Leuven, Belgium
| | | | - Nicolas Verhaert
- Department of Neurosciences, KU Leuven, Herestraat 49, 3001, Leuven, Belgium
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital of Leuven, Herestraat 49, 3001, Leuven, Belgium
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2
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Joris PX, Verschooten E, Mc Laughlin M, Versteegh C, van der Heijden M. Frequency selectivity in monkey auditory nerve studied with suprathreshold multicomponent stimuli. Hear Res 2024; 443:108964. [PMID: 38277882 DOI: 10.1016/j.heares.2024.108964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024]
Abstract
Data from non-human primates can help extend observations from non-primate species to humans. Here we report measurements on the auditory nerve of macaque monkeys in the context of a controversial topic important to human hearing. A range of techniques have been used to examine the claim, which is not generally accepted, that human frequency tuning is sharper than traditionally thought, and sharper than in commonly used animal models. Data from single auditory-nerve fibers occupy a pivotal position to examine this claim, but are not available for humans. A previous study reported sharper tuning in auditory-nerve fibers of macaque relative to the cat. A limitation of these and other single-fiber data is that frequency selectivity was measured with tonal threshold-tuning curves, which do not directly assess spectral filtering and whose shape is sharpened by cochlear nonlinearity. Our aim was to measure spectral filtering with wideband suprathreshold stimuli in the macaque auditory nerve. We obtained responses of single nerve fibers of anesthetized macaque monkeys and cats to a suprathreshold, wideband, multicomponent stimulus designed to allow characterization of spectral filtering at any cochlear locus. Quantitatively the differences between the two species are smaller than in previous studies, but consistent with these studies the filters obtained show a trend of sharper tuning in macaque, relative to the cat, for fibers in the basal half of the cochlea. We also examined differences in group delay measured on the phase data near the characteristic frequency versus in the low-frequency tail. The phase data are consistent with the interpretation of sharper frequency tuning in monkey in the basal half of the cochlea. We conclude that use of suprathreshold, wide-band stimuli supports the interpretation of sharper frequency selectivity in macaque nerve fibers relative to the cat, although the difference is less marked than apparent from the assessment with tonal threshold-based data.
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Affiliation(s)
- P X Joris
- Lab of Auditory Neurophysiology, KU Leuven, O&N2 KU Leuven, Herestraat 49 bus 1021, Leuven B-3000, Belgium.
| | - E Verschooten
- Lab of Auditory Neurophysiology, KU Leuven, O&N2 KU Leuven, Herestraat 49 bus 1021, Leuven B-3000, Belgium
| | - M Mc Laughlin
- Lab of Auditory Neurophysiology, KU Leuven, O&N2 KU Leuven, Herestraat 49 bus 1021, Leuven B-3000, Belgium
| | - Cpc Versteegh
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
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3
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Optical Coherence Tomography-Based Atlas of the Human Cochlear Hook Region. J Clin Med 2022; 12:jcm12010238. [PMID: 36615042 PMCID: PMC9820872 DOI: 10.3390/jcm12010238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/30/2022] Open
Abstract
Advancements in intracochlear diagnostics, as well as prosthetic and regenerative inner ear therapies, rely on a good understanding of cochlear microanatomy. The human cochlea is very small and deeply embedded within the densest skull bone, making nondestructive visualization of its internal microstructures extremely challenging. Current imaging techniques used in clinical practice, such as MRI and CT, fall short in their resolution to visualize important intracochlear landmarks, and histological analysis of the cochlea cannot be performed on living patients without compromising their hearing. Recently, optical coherence tomography (OCT) has been shown to be a promising tool for nondestructive micrometer resolution imaging of the mammalian inner ear. Various studies performed on human cadaveric tissue and living animals demonstrated the ability of OCT to visualize important cochlear microstructures (scalae, organ of Corti, spiral ligament, and osseous spiral lamina) at micrometer resolution. However, the interpretation of human intracochlear OCT images is non-trivial for researchers and clinicians who are not yet familiar with this novel technology. In this study, we present an atlas of intracochlear OCT images, which were acquired in a series of 7 fresh and 10 fresh-frozen human cadaveric cochleae through the round window membrane and describe the qualitative characteristics of visualized intracochlear structures. Likewise, we describe several intracochlear abnormalities, which could be detected with OCT and are relevant for clinical practice.
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4
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Badash I, Quiñones PM, Oghalai KJ, Wang J, Lui CG, Macias-Escriva F, Applegate BE, Oghalai JS. Endolymphatic Hydrops is a Marker of Synaptopathy Following Traumatic Noise Exposure. Front Cell Dev Biol 2021; 9:747870. [PMID: 34805158 PMCID: PMC8602199 DOI: 10.3389/fcell.2021.747870] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/20/2021] [Indexed: 12/28/2022] Open
Abstract
After acoustic trauma, there can be loss of synaptic connections between inner hair cells and auditory neurons in the cochlea, which may lead to hearing abnormalities including speech-in-noise difficulties, tinnitus, and hyperacusis. We have previously studied mice with blast-induced cochlear synaptopathy and found that they also developed a build-up of endolymph, termed endolymphatic hydrops. In this study, we used optical coherence tomography to measure endolymph volume in live CBA/CaJ mice exposed to various noise intensities. We quantified the number of synaptic ribbons and postsynaptic densities under the inner hair cells 1 week after noise exposure to determine if they correlated with acute changes in endolymph volume measured in the hours after the noise exposure. After 2 h of noise at an intensity of 95 dB SPL or below, both endolymph volume and synaptic counts remained normal. After exposure to 2 h of 100 dB SPL noise, mice developed endolymphatic hydrops and had reduced synaptic counts in the basal and middle regions of the cochlea. Furthermore, round-window application of hypertonic saline reduced the degree of endolymphatic hydrops that developed after 100 dB SPL noise exposure and partially prevented the reduction in synaptic counts in the cochlear base. Taken together, these results indicate that endolymphatic hydrops correlates with noise-induced cochlear synaptopathy, suggesting that these two pathologic findings have a common mechanistic basis.
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Affiliation(s)
- Ido Badash
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Patricia M Quiñones
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Kevin J Oghalai
- Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
| | - Juemei Wang
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Christopher G Lui
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Frank Macias-Escriva
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Brian E Applegate
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States.,Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States.,Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
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5
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Lui CG, Kim W, Dewey JB, Macías-Escrivá FD, Ratnayake K, Oghalai JS, Applegate BE. In vivo functional imaging of the human middle ear with a hand-held optical coherence tomography device. BIOMEDICAL OPTICS EXPRESS 2021; 12:5196-5213. [PMID: 34513251 PMCID: PMC8407818 DOI: 10.1364/boe.430935] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/02/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
We describe an optical coherence tomography and vibrometry system designed for portable hand-held usage in the otology clinic on awake patients. The system provides clinically relevant point-of-care morphological imaging with 14-44 µm resolution and functional vibratory measures with sub-nanometer sensitivity. We evaluated various new approaches for extracting functional information including a multi-tone stimulus, a continuous chirp stimulus, and alternating air and bone stimulus. We also explored the vibratory response over an area of the tympanic membrane (TM) and generated TM thickness maps. Our results suggest that the system can provide real-time in vivo imaging and vibrometry of the ear and could prove useful for investigating otologic pathology in the clinic setting.
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Affiliation(s)
- Christopher G. Lui
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
- These authors contributed equally to this work
| | - Wihan Kim
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
- These authors contributed equally to this work
| | - James B. Dewey
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
| | - Frank D. Macías-Escrivá
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
| | - Kumara Ratnayake
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
| | - John S. Oghalai
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
| | - Brian E. Applegate
- Department of Otolaryngology - Head and Neck Surgery, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Suite 5708, Los Angeles, CA 90033, USA
- Department of Biomedical Engineering, University of Southern California, 1042 Downey Way, Denney Research Center (DRB) 140, Los Angeles, CA 90089, USA
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6
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Badash I, Applegate BE, Oghalai JS. In Vivo Cochlear imaging provides a tool to study endolymphatic hydrops. J Vestib Res 2021; 31:269-276. [PMID: 33136083 DOI: 10.3233/ves-200718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Exposure to noise trauma, such as that from improvised explosive devices, can lead to sensorineural hearing loss and a reduced quality of life. In order to elucidate the mechanisms underlying noise-induced hearing loss, we have adapted optical coherence tomography (OCT) for real-time cochlear visualization in live mice after blast exposure. We demonstrated that endolymphatic hydrops develops following blast injury, and that this phenomenon may be associated with glutamate excitotoxicity and cochlear synaptopathy. Additionally, osmotic stabilization of endolymphatic hydrops partially rescues cochlear synapses after blast trauma. OCT is thus a valuable research tool for investigating the mechanisms underlying acoustic trauma and dynamic changes in endolymph volume. It may also help with the diagnosis and treatment of human hearing loss and/or vertigo in the near future.
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Affiliation(s)
- Ido Badash
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, USA
| | - Brian E Applegate
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, USA
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA, USA
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7
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Tsai TY, Chen TH, Chen HC, Chueh CB, Huang YP, Hung YP, Tsai MT, Baumann B, Wang CH, Lee HC. Quantitative spectroscopic comparison of the optical properties of mouse cochlea microstructures using optical coherence tomography at 1.06 µm and 1.3 µm wavelengths. BIOMEDICAL OPTICS EXPRESS 2021; 12:2339-2352. [PMID: 33996233 PMCID: PMC8086459 DOI: 10.1364/boe.419378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Currently, the cochlear implantation procedure mainly relies on using a hand lens or surgical microscope, where the success rate and surgery time strongly depend on the surgeon's experience. Therefore, a real-time image guidance tool may facilitate the implantation procedure. In this study, we performed a systematic and quantitative analysis on the optical characterization of ex vivo mouse cochlear samples using two swept-source optical coherence tomography (OCT) systems operating at the 1.06-µm and 1.3-µm wavelengths. The analysis results demonstrated that the 1.06-µm OCT imaging system performed better than the 1.3-µm OCT imaging system in terms of the image contrast between the cochlear conduits and the neighboring cochlear bony wall structure. However, the 1.3-µm OCT imaging system allowed for greater imaging depth of the cochlear samples because of decreased tissue scattering. In addition, we have investigated the feasibility of identifying the electrode of the cochlear implant within the ex vivo cochlear sample with the 1.06-µm OCT imaging. The study results demonstrated the potential of developing an image guidance tool for the cochlea implantation procedure as well as other otorhinolaryngology applications.
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Affiliation(s)
- Ting-Yen Tsai
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan
| | - Ting-Hao Chen
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan
| | - Hsin-Chien Chen
- Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Chuan-Bor Chueh
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan
| | - Yin-Peng Huang
- Graduate Institute of Networking and Multimedia, National Taiwan University, No 1, Sec. 4 Roosevelt Rd., Taipei, Taiwan
| | - Yi-Ping Hung
- Graduate Institute of Networking and Multimedia, National Taiwan University, No 1, Sec. 4 Roosevelt Rd., Taipei, Taiwan
| | - Meng-Tsan Tsai
- Department of Electrical Engineering, Chang Gung University, Taoyuan, Taiwan
- Department of Neurology, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Chih-Hung Wang
- Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- Taichung Armed Forces General Hospital, Taichung, Taiwan
| | - Hsiang-Chieh Lee
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
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8
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Won J, Porter RG, Novak MA, Youakim J, Sum A, Barkalifa R, Aksamitiene E, Zhang A, Nolan R, Shelton R, Boppart SA. In vivo dynamic characterization of the human tympanic membrane using pneumatic optical coherence tomography. JOURNAL OF BIOPHOTONICS 2021; 14:e202000215. [PMID: 33439538 PMCID: PMC7935452 DOI: 10.1002/jbio.202000215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/14/2020] [Accepted: 07/19/2020] [Indexed: 05/05/2023]
Abstract
Decreased mobility of the human eardrum, the tympanic membrane (TM), is an essential indicator of a prevalent middle ear infection. The current diagnostic method to assess TM mobility is via pneumatic otoscopy, which provides subjective and qualitative information of subtle motion. In this study, a handheld spectral-domain pneumatic optical coherence tomography system was developed to simultaneously measure the displacement of the TM, air pressure inputs applied to a sealed ear canal, and to perform digital pneumatic otoscopy. A novel approach based on quantitative parameters is presented to characterize spatial and temporal variations of the dynamic TM motion. Furthermore, the TM motions of normal middle ears are compared with those of ears with middle ear infections. The capability of noninvasively measuring the rapid motion of the TM is beneficial to understand the complex dynamics of the human TM, and can ultimately lead to improved diagnosis and management of middle ear infections.
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Affiliation(s)
- Jungeun Won
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, Urbana, Illinois
| | - Ryan G. Porter
- Department of Otolaryngology, Carle Foundation Hospital, Urbana, Illinois
| | - Michael A. Novak
- Department of Otolaryngology, Carle Foundation Hospital, Urbana, Illinois
| | - Jon Youakim
- Department of Pediatrics, Carle Foundation Hospital, Urbana, Illinois
| | - Ada Sum
- Department of Pediatrics, Carle Foundation Hospital, Urbana, Illinois
| | - Ronit Barkalifa
- Beckman Institute for Advanced Science and Technology, Urbana, Illinois
| | - Edita Aksamitiene
- Beckman Institute for Advanced Science and Technology, Urbana, Illinois
| | | | | | | | - Stephen A. Boppart
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Beckman Institute for Advanced Science and Technology, Urbana, Illinois
- PhotoniCare, Inc., Champaign, Illinois
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, Illinois
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9
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Olson ES, Strimbu CE. Cochlear mechanics: new insights from vibrometry and Optical Coherence Tomography. CURRENT OPINION IN PHYSIOLOGY 2020; 18:56-62. [PMID: 33103018 DOI: 10.1016/j.cophys.2020.08.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The cochlea is a complex biological machine that transduces sound-induced mechanical vibrations to neural signals. Hair cells within the sensory tissue of the cochlea transduce vibrations into electrical signals, and exert electromechanical feedback that enhances the passive frequency separation provided by the cochlea's traveling wave mechanics; this enhancement is termed cochlear amplification. The vibration of the sensory tissue has been studied with many techniques, and the current state of the art is optical coherence tomography (OCT). The OCT technique allows for motion of intra-organ structures to be measured in vivo at many layers within the sensory tissue, at several angles and in previously under-explored species. OCT-based observations are already impacting our understanding of hair cell excitation and cochlear amplification.
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Affiliation(s)
- Elizabeth S Olson
- Department of Otolaryngolgy Head and Neck Surgery, Vagelos College of Physicians and Surgeons, Columbia University, 630 W 168th St, New York, NY 10032.,Department Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue,New York, NY 10027
| | - C Elliott Strimbu
- Department of Otolaryngolgy Head and Neck Surgery, Vagelos College of Physicians and Surgeons, Columbia University, 630 W 168th St, New York, NY 10032
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10
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Kim S, Oghalai JS, Applegate BE. Noise and sensitivity in optical coherence tomography based vibrometry. OPTICS EXPRESS 2019; 27:33333-33350. [PMID: 31878404 PMCID: PMC7046037 DOI: 10.1364/oe.27.033333] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/08/2019] [Accepted: 10/11/2019] [Indexed: 05/30/2023]
Abstract
There is growing interest in using the exquisite phase sensitivity of optical coherence tomography (OCT) to measure the vibratory response in organ systems such as the middle and inner ear. Using frequency domain analysis, it is possible to achieve picometer sensitivity to vibration over a wide frequency band. Here we explore the limits of the frequency domain vibratory sensitivity due to additive noise and consider the implication of phase noise statistics on the estimation of vibratory amplitude and phase. Noise statistics are derived in both the Rayleigh (s/n = 0) and Normal distribution (s/n > 3) limits. These theoretical findings are explored using simulation and verified with experiments using a swept-laser system and a piezo electric element. A metric for sensitivity is proposed based on the 98% confidence interval for the Rayleigh distribution.
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Affiliation(s)
- Sangmin Kim
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - John S. Oghalai
- Caruso Department of Otolaryngology – Head & Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Brian E. Applegate
- Caruso Department of Otolaryngology – Head & Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
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11
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Kim W, Kim S, Huang S, Oghalai JS, Applegate BE. Picometer scale vibrometry in the human middle ear using a surgical microscope based optical coherence tomography and vibrometry system. BIOMEDICAL OPTICS EXPRESS 2019; 10:4395-4410. [PMID: 31565497 PMCID: PMC6757470 DOI: 10.1364/boe.10.004395] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 05/10/2023]
Abstract
We have developed a highly phase stable optical coherence tomography and vibrometry system that attaches directly to the accessory area of a surgical microscope common to both the otology clinic and operating room. Careful attention to minimizing sources of phase noise has enabled a system capable of measuring vibrations of the middle ear with a sensitivity of < 5 pm in an awake human patient. The system is shown to be capable of collecting a wide range of information on the morphology and function of the ear in live subjects, including frequency tuning curves below the hearing threshold, maps of tympanic membrane vibrational modes and thickness, and measures of distortion products due to the nonlinearities in the cochlear amplifier.
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Affiliation(s)
- Wihan Kim
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Sangmin Kim
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Shuning Huang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA
| | - John S. Oghalai
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Brian E. Applegate
- Department of Otolaryngology–Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
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