1. Articles from Alfred L. Nuttall

    1-22 of 22
    1. Revealing the morphology and function of the cochlea and middle ear with optical coherence tomography

      Revealing the morphology and function of the cochlea and middle ear with optical coherence tomography

      Optical coherence tomography (OCT) has revolutionized physiological studies of the hearing organ, the vibration and morphology of which can now be measured without opening the surrounding bone. In this review, we provide an overview of OCT as used in the otological research, describing advances and different techniques in vibrometry, angiography, and structural imaging.

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    2. Minimal basilar membrane motion in low-frequency hearing

      Minimal basilar membrane motion in low-frequency hearing

      To perceive speech, the brain relies on inputs from sensory cells located near the top of the spiral-shaped cochlea. This low-frequency region of the inner ear is anatomically difficult to access, and it has not previously been possible to study its mechanical response to sound in intact preparations. Here, we used optical coherence tomography to image sound-evoked vibration inside the intact cochlea. We show that low-frequency sound moves a small portion of the basilar membrane, and that the motion declines in an exponential manner across the basilar membrane. Hence, the response of the hearing organ to speech-frequency sounds is different ...

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    3. Minimally invasive surgical method to detect sound processing in the cochlear apex by optical coherence tomography

      Minimally invasive surgical method to detect sound processing in the cochlear apex by optical coherence tomography

      Sound processing in the inner ear involves separation of the constituent frequencies along the length of the cochlea. Frequencies relevant to human speech (100 to 500 Hz) are processed in the apex region. Among mammals, the guinea pig cochlear apex processes similar frequencies and is thus relevant for the study of speech processing in the cochlea. However, the requirement for extensive surgery has challenged the optical accessibility of this area to investigate cochlear processing of signals without significant intrusion. A simple method is developed to provide optical access to the guinea pig cochlear apex in two directions with minimal surgery ...

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    4. Development of a phase-sensitive Fourier domain optical coherence tomography system to measure mouse organ of Corti vibrations in two cochlear turns

      Development of a phase-sensitive Fourier domain optical coherence tomography system to measure mouse organ of Corti vibrations in two cochlear turns

      In this study, we have developed a phase-sensitive Fourier-domain optical coherence tomography system to simultaneously measure the in vivo inner ear vibrations in the hook area and second turn of the mouse cochlea. This technical development will enable measurement of intra-cochlear distortion products at ideal locations such as the distortion product generation site and reflection site. This information is necessary to un-mix the complex mixture of intra-cochlear waves comprising the DPOAE and thus leads to the non-invasive identification of the local region of cochlear damage.

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    5. Two dimensional vibrations of the guinea pig apex organ of Corti measured in vivo using phase sensitive Fourier domain optical coherence tomography

      Two dimensional vibrations of the guinea pig apex organ of Corti measured in vivo using phase sensitive Fourier domain optical coherence tomography

      In this study, we measure the in vivo apical-turn vibrations of the guinea pig organ of Corti in both axial and radial directions using phase-sensitive Fourier domain optical coherence tomography. The apical turn in guinea pig cochlea has best frequencies around 100 – 500 Hz which are relevant for human speech. Prior measurements of vibrations in the guinea pig apex involved opening the otic capsule, which has been questioned on the basis of the resulting changes to cochlear hydrodynamics. Here this limitation is overcome by measuring the vibrations through bone without opening the otic capsule. Furthermore, we have significantly reduced the ...

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    6. Changes in cochlear blood flow in mice due to loud sound exposure measured with Doppler optical microangiography and laser Doppler flowmetry

      Changes in cochlear blood flow in mice due to loud sound exposure measured with Doppler optical microangiography and laser Doppler flowmetry

      In this work we determined the contributions of loud sound exposure (LSE) on cochlear blood flow (CoBF) in an in vivo anesthetized mouse model. A broadband noise system (20 kHz bandwidth) with an intensity of 119 dB SPL, was used for a period of one hour to produce a loud sound stimulus. Two techniques were used to study the changes in blood flow, a Doppler optical microangiography (DOMAG) system; which can measure the blood flow within individual cochlear vessels, and a laser Doppler flowmetry (LDF) system; which averages the blood flow within a volume (a hemisphere of ~1.5 mm ...

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    7. Reflective type objective based spectral-domain phase-sensitive optical coherence tomography for high-sensitive structural and functional imaging of cochlear microstructures through intact bone of an excised guinea pig cochlea

      Reflective type objective based spectral-domain phase-sensitive optical coherence tomography for high-sensitive structural and functional imaging of cochlear microstructures through intact bone of an excised guinea pig cochlea

      Most of the optical coherence tomographic (OCT) systems for high resolution imaging of biological specimens are based on refractive type microscope objectives, which are optimized for specific wave length of the optical source. In this study, we present the feasibility of using commercially available reflective type objective for high sensitive and high resolution structural and functional imaging of cochlear microstructures of an excised guinea pig through intact temporal bone. Unlike conventional refractive type microscopic objective, reflective objective are free from chromatic aberrations due to their all-reflecting nature and can support a broadband of spectrum with very high light collection efficiency.

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    8. Feature Of The Week 3/17/13: Using Optical Coherence Tomography to Study Mechanisms of Hearing

      Feature Of The Week 3/17/13: Using Optical Coherence Tomography to Study Mechanisms of Hearing

      The Oregon Hearing Research Centre (OHRC) at the Oregon Health and Science University (OHSU), Portland, Oregon is one of the strongest hearing research groups in the world, and one of the early adopters of optical coherence tomography technology in the field of hearing research. Researchers at OHRC have developed a couple of novel OCT based imaging technologies for functional imaging of middle and inner ear. This includes high-speed OCT system for in vivo imaging of microstructural morphology and micvascular perfusion within the cochlea [1,2], phase-sensitive time-domain and Fourier domain OCT for studying cochlear micromechanics [3,4] and middle ear ...

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    9. Measurement of in vivo basal-turn vibrations of the organ of Corti using phase-sensitive Fourier domain optical coherence tomography

      Measurement of in vivo basal-turn vibrations of the organ of Corti using phase-sensitive Fourier domain optical coherence tomography

      A major reason we can perceive faint sounds and communicate in noisy environments is that the outer hair cells of the organ of Corti enhance the sound-evoked motions inside the cochlea. To understand how the organ of Corti works, we have built and tested the phase-sensitive Fourier domain optical coherence tomography (PSFDOCT) system. This system has key advantages over our previous time domain OCT system [1]. The PSFDOCT system has better signal to noise and simultaneously acquires vibration data from all points along the optical-axis [2]. Feasibility of this system to measure in vitro cochlear vibrations in the apex was ...

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    10. Depth-resolved dual-beamlet vibrometry based on Fourier domain low coherence interferometry

      Depth-resolved dual-beamlet vibrometry based on Fourier domain low coherence interferometry

      We present an optical vibrometer based on delay-encoded, dual-beamlet phase-sensitive Fourier domain interferometric system to provide depth-resolved subnanometer scale vibration information from scattering biological specimens. System characterization, calibration, and preliminary vibrometry with biological specimens were performed. The proposed system has the potential to provide both amplitude and direction of vibration of tissue microstructures on a single two-dimensional plane.

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    11. Feature Of The Week 6/17/12: Middle Ear Vibrometry of Human Cadaver Temporal Bone with Spectral Domain Phase-Sensitive Optical Coherence Tomography

      Feature Of The Week 6/17/12: Middle Ear Vibrometry of Human Cadaver Temporal Bone with Spectral Domain Phase-Sensitive Optical Coherence Tomography

      Hearing loss is the most frequent sensory deficit in the human population, affecting more than 250 million people in the world. The National Center for Health Statistics estimates that 37 million adults (17%) in the United States have hearing difficulty. Analysis of a large database of audiometric records from the University of Minnesota reveals that 39% of patients diagnosed with hearing loss have conductive hearing loss (CHL) either alone (15%) or in combination with SNHL (24%). There are several contemporary audiological tests that are commonly used to diagnose middle ear function for CHL. However, these contemporary tests of middle ear ...

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    12. Feasibility of spectral-domain phase-sensitive optical coherence tomography for middle ear vibrometry

      Feasibility of spectral-domain phase-sensitive optical coherence tomography for middle ear vibrometry

      We describe a novel application of spectral-domain phase-sensitive optical coherence tomography (SD PS-OCT) to detect the tiny motions of the middle ear structures, such as the tympanic membrane and ossicular chain, and their morphological features for differential diagnosis of CHL. This technique has the potential to provide meaningful vibration of ossicles with a vibration sensitivity of ∼ 0.5  nm at 1 kHz of acoustic stimulation. To the best of our knowledge, this is the first demonstration of depth-resolved vibration imaging of ossicles with a PS-OCT system at a nanometer scale.

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    13. Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing

      Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing

      A multidisciplinary research groups spanning several countries (USA, China, Sweden) are using optical coherence tomography (OCT) to investigate minute changes in hair cells within the cochlea - the auditory portion of the inner ear. Below is a summary of their work. Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating ...

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    14. In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

      In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea

      Background Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. Methodology/Principal Findings Using in vivo optical coherence tomography, we demonstrate that outer hair cells in ...

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    15. Simultaneous depth-resolved imaging of sub-nanometer scale ossicular vibrations and morphological features of the human-cadaver middle ear with spectral-domain phase-sensitive optical coherence tomography

      Simultaneous depth-resolved imaging of sub-nanometer scale ossicular vibrations and morphological features of the human-cadaver middle ear with spectral-domain phase-sensitive optical coherence tomography

      We describe a novel method for the detection of the tiny motions of the middle ear (ME) ossicles and their morphological features with a spectral-domain phase sensitive optical coherence tomography (PS-OCT). Laser Doppler Vibrometry (LDV) and its variations are the most extensively used methods for studding the vibrational modes of the ME. However, most techniques are limited to single point analysis methods, and do not have the ability to provide depth resolved simultaneous imaging of multiple points on the ossicles especially with the intact eardrum. Consequently, the methods have the limited ability to provide relative vibration information at these points ...

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    16. Absolute measurement of subnanometer scale vibration of cochlear partition of an excised guinea pig cochlea using spectral-domain phase-sensitive optical coherence tomography

      Absolute measurement of subnanometer scale vibration of cochlear partition of an excised guinea pig cochlea using spectral-domain phase-sensitive optical coherence tomography

      Direct measurement of absolute vibration parameters from different locations within the mammalian organ of Corti is crucial for understanding the hearing mechanics such as how sound propagates through the cochlea and how sound stimulates the vibration of various structures of the cochlea, namely, basilar membrane (BM), recticular lamina, outer hair cells and tectorial membrane (TM). In this study we demonstrate the feasibility a modified phase-sensitive spectral domain optical coherence tomography system to provide subnanometer scale vibration information from multiple angles within the imaging beam. The system has the potential to provide depth resolved absolute vibration measurement of tissue microstructures from ...

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    17. Imaging Organ of Corti Vibration Using Fourier-Domain OCT

      Imaging Organ of Corti Vibration Using Fourier-Domain OCT

      Measuring the sound stimulated vibration from various structures in the organ of Corti is important in understanding how the small vibrations are amplified and detected. In this study we examine the feasibility of using phase-sensitive Fourier domain optical coherence tomography (PSFD-OCT) to measure vibration of the cellular structures of the organ of Corti. PSFD-OCT is a low coherence interferrometry system where the interferrogram is detected as a function of wavelength. The phase of the Fourier transformation of the detected spectra contains path deference (between the sample arm and the reference arm) information of the interferometer. In PSFD-OCT this phase is ...

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    18. A differentially amplified motion in the ear for near-threshold sound detection

      A differentially amplified motion in the ear for near-threshold sound detection

      The ear is a remarkably sensitive pressure fluctuation detector. In guinea pigs, behavioral measurements indicate a minimum detectable sound pressure of ~20 μPa at 16 kHz. Such faint sounds produce 0.1-nm basilar membrane displacements, a distance smaller than conformational transitions in ion channels. It seems that noise within the auditory system would swamp such tiny motions, making weak sounds imperceptible. Here we propose a new mechanism contributing to a resolution of this problem and validate it through direct measurement. We hypothesized that vibration at the apical side of hair cells is enhanced compared with that at the commonly measured ...

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    19. Volumetric in-vivo imaging of intra-cochlear microstructures and microvascular perfusion in mice using high-speed spectral domain optical coherence tomography and ultra-high sensitive optical microangiography

      Volumetric in-vivo imaging of intra-cochlear microstructures and microvascular perfusion in mice using high-speed spectral domain optical coherence tomography and ultra-high sensitive optical microangiography

      Studying the inner ear microstructures and microvascular dynamics is extremely important to understand the cochlear function and to further advance the diagnosis, prevention and treatment of many otologic disorders. There is considerable interest in developing new methods for in vivo imaging of the complex anatomy of the mammalian cochlea and the micro vascular perfusion within it for both clinical as well as fundamental studies. In this study, we explored the feasibility of high-speed spectral domain optical coherence tomography (SD-OCT) and ultra-high sensitive optical microangiography (UHS-OMAG) for volumetric in vivo imaging of intracochlear microstructures and microvascular perfusion in mice, respectively.

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    20. Volumetric In Vivo Imaging of Microvascular Perfusion Within the Intact Cochlea in Mice Using Ultra-High Sensitive Optical Microangiography

      Volumetric In Vivo Imaging of Microvascular Perfusion Within the Intact Cochlea in Mice Using Ultra-High Sensitive Optical Microangiography
      Studying the inner ear microvascular dynamics is extremely important to understand the cochlear function and to further advance the diagnosis, prevention, and treatment of many otologic disorders. However, there is currently no effective imaging tool available that is able to access the blood flow within the intact cochlea. In this paper, we report the use of an ultrahigh sensitive optical micro-angiography (UHS-OMAG) imaging system to image 3-D microvascular perfusion within the intact cochlea in living mice. The UHS-OMAG image system used in this study is based on spectral domain optical coherence tomography, which uses a broadband light source centered at ...
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    21. Phase-sensitive optical coherence tomography imaging of the tissue motion within the organ of Corti at a subnanometer scale: a preliminary study

      Phase-sensitive optical coherence tomography imaging of the tissue motion within the organ of Corti at a subnanometer scale: a preliminary study
      Hearing loss can mean severe impairment to the quality of life. However, the biomechanical mechanisms of how the hearing organ, i.e., the organ of Corti (OC), responds to sound are still elusive, largely because there is currently no means available to image the 3-D motion characteristics of the OC. We present a novel use of the phase-sensitive spectral domain optical coherence tomography (PSOCT) to characterize the motion of cellular compartments within the OC at a subnanometer scale. The PSOCT system operates at 1310 nm with a spatial resolution of ~16 µm and an imaging speed of 47,000 A-lines ...
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    22. Volumetric in vivo imaging of intracochlear microstructures in mice by high-speed spectral domain optical coherence tomography

      Volumetric in vivo imaging of intracochlear microstructures in mice by high-speed spectral domain optical coherence tomography
      There is considerable interest in developing new methods for in vivo imaging of the complex anatomy of the mammalian cochlea for clinical as well as fundamental studies. In this study, we explored, the feasibility of spectral domain optical coherence tomography (SD-OCT) for 3-D in vivo imaging of the cochlea in mice. The SD-OCT system employed in this study used a broadband light source centered at 1300 nm, and the imaging speed of the system was 47,000 A-scans per second using the InGaAs camera. The system was capable of providing fully processed, high-resolution B-scan images [512 (axial)×128 (lateral) pixels ...
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    1-22 of 22
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    1. (22 articles) Oregon Health & Science University
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    Volumetric in vivo imaging of intracochlear microstructures in mice by high-speed spectral domain optical coherence tomography Phase-sensitive optical coherence tomography imaging of the tissue motion within the organ of Corti at a subnanometer scale: a preliminary study Volumetric In Vivo Imaging of Microvascular Perfusion Within the Intact Cochlea in Mice Using Ultra-High Sensitive Optical Microangiography Volumetric in-vivo imaging of intra-cochlear microstructures and microvascular perfusion in mice using high-speed spectral domain optical coherence tomography and ultra-high sensitive optical microangiography A differentially amplified motion in the ear for near-threshold sound detection Simultaneous depth-resolved imaging of sub-nanometer scale ossicular vibrations and morphological features of the human-cadaver middle ear with spectral-domain phase-sensitive optical coherence tomography In Vivo Outer Hair Cell Length Changes Expose the Active Process in the Cochlea Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing Feature Of The Week 6/17/12: Middle Ear Vibrometry of Human Cadaver Temporal Bone with Spectral Domain Phase-Sensitive Optical Coherence Tomography Feature Of The Week 3/17/13: Using Optical Coherence Tomography to Study Mechanisms of Hearing Ageing and glaucoma progression of the retinal nerve fibre layer using spectral‐domain optical coherence tomography analysis Comparison of optical coherence tomography-guided versus intravascular ultrasound-guided percutaneous coronary intervention: Rationale and Design of a Randomized, controlled OCTIVUS trial