1. Articles mentioning both Texas A&M University and John S. Oghalai

    1-19 of 19
    1. Noise and sensitivity in optical coherence tomography based vibrometry

      Noise and sensitivity in optical coherence tomography based vibrometry
      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 ...
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    2. Picometer scale vibrometry in the human middle ear using a surgical microscope based optical coherence tomography and vibrometry system

      Picometer scale vibrometry in the human middle ear using a surgical microscope based optical coherence tomography and vibrometry system
      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 ...
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    3. Organ of Corti vibration within the intact gerbil cochlea measured by volumetric optical coherence tomography and vibrometry

      Organ of Corti vibration within the intact gerbil cochlea measured by volumetric optical coherence tomography and vibrometry
      There is indirect evidence that the mammalian cochlea in the low-frequency apical and the more commonly-studied high-frequency basal regions function in fundamentally different ways. Here, we directly tested this hypothesis by measuring sound-induced vibrations of the organ of Corti (OoC) at three turns of the gerbil cochlea using volumetric optical coherence tomography vibrometry (VOCTV), an approach that permits non-invasive imaging through the bone. In the apical turn, there was little ...
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    4. Osmotic stabilization prevents cochlear synaptopathy after blast trauma

      Osmotic stabilization prevents cochlear synaptopathy after blast trauma
      Traumatic noise causes hearing loss by damaging sensory hair cells and their auditory synapses. There are no treatments. Here, we investigated mice exposed to a blast wave approximating a roadside bomb. In vivo cochlear imaging revealed an increase in the volume of endolymph, the fluid within scala media, termed endolymphatic hydrops. Endolymphatic hydrops, hair cell loss, and cochlear synaptopathy were initiated by trauma to the mechanosensitive hair cell stereocilia and ...
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    5. Endoscopic optical coherence tomography enables morphological and subnanometer vibratory imaging of the porcine cochlea through the round window

      Endoscopic optical coherence tomography enables morphological and subnanometer vibratory imaging of the porcine cochlea through the round window
      A highly phase stable hand-held (HH) endoscopic system has been developed for optical coherence tomography and vibrometry. Designed to transit the ear canal to the middle ear space and peer through the round window (RW), it is capable of imaging the vibratory function of the cochlear soft tissues with subnanometer scale sensitivity. A side-looking, 9 cm long rigid endoscope with a distal diameter of 1.2 mm, was able to ...
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    6. ELHnet: a convolutional neural network for classifying cochlear endolymphatic hydrops imaged with optical coherence tomography

      ELHnet: a convolutional neural network for classifying cochlear endolymphatic hydrops imaged with optical coherence tomography
      Detection of endolymphatic hydrops is important for diagnosing Menieres disease, and can be performed non-invasively using optical coherence tomography (OCT) in animal models as well as potentially in the clinic. Here, we developed ELHnet, a convolutional neural network to classify endolymphatic hydrops in a mouse model using learned features from OCT images of mice cochleae. We trained ELHnet on 2159 training and validation images from 17 mice, using only the ...
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    7. Computer-aided detection and quantification of endolymphatic hydrops within the mouse cochlea in vivo using optical coherence tomography

      Computer-aided detection and quantification of endolymphatic hydrops within the mouse cochlea in vivo using optical coherence tomography
      Diseases that cause hearing loss and/or vertigo in humans such as Menieres disease are often studied using animal models. The volume of endolymph within the inner ear varies with these diseases. Here, we used a mouse model of increased endolymph volume, endolymphatic hydrops, to develop a computer-aided objective approach to measure endolymph volume from images collected in vivo using optical coherence tomography. The displacement of Reissners membrane from its ...
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    8. High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography

      High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography
      Swept-laser sources offer a number of advantages for Phase-sensitive Optical Coherence Tomography (PhOCT). However, inter- and intra-sweep variability leads to calibration errors that adversely affect phase sensitivity. While there are several approaches to overcoming this problem, our preferred method is to simply calibrate every sweep of the laser. This approach offers high accuracy and phase stability at the expense of a substantial processing burden. In this approach, the Hilbert phase ...
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    9. Phase-sensitive optical coherence tomography-based vibrometry using a highly phase-stable akinetic swept laser source

      Phase-sensitive optical coherence tomography-based vibrometry using a highly phase-stable akinetic swept laser source
      Phase-sensitive Optical Coherence Tomography (PhOCT) is an emerging tool for in vivo investigation of the vibratory function of the intact middle and inner ear. PhOCT is able to resolve micron scale tissue morphology in three dimensions as well as measure picometer scale motion at each spatial position. Most PhOCT systems to date have relied upon the phase stability offered by spectrometer detection. On the other hand swept laser source based ...
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    10. Miniature, minimally invasive, tunable endoscope for investigation of the middle ear

      Miniature, minimally invasive, tunable endoscope for investigation of the middle ear
      We demonstrate a miniature, tunable, minimally invasive endoscope for diagnosis of the auditory system. The probe is designed to sharply image anatomical details of the middle ear without the need for physically adjusting the position of the distal end of the endoscope. This is achieved through the addition of an electrowetted, tunable, electronically-controlled lens to the optical train. Morphological imaging is enabled by scanning light emanating from an optical coherence ...
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    11. Feature Of The Week 04/05/15: Noninvasive in vivo Imaging Reveals Differences Between Tectorial Membrane and Basilar Membrane Traveling Waves in the Mouse Cochlea

      Feature Of The Week 04/05/15: Noninvasive in vivo Imaging Reveals Differences Between Tectorial Membrane and Basilar Membrane Traveling Waves in the Mouse Cochlea
      Sound is encoded within the auditory portion of the inner ear, the cochlea, after propagating down its length as a traveling wave. For over half a century, vibratory measurements to study cochlear traveling waves have been made using invasive approaches such as laser Doppler vibrometry. While these studies have provided critical information regarding the non-linear processes within the living cochlea that increase the amplitude of vibration and sharpen frequency tuning ...
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    12. Phase-sensitive optical coherence tomography using an Vernier-tuned distributed Bragg reflector swept laser in the mouse middle ear

      Phase-sensitive optical coherence tomography using an Vernier-tuned distributed Bragg reflector swept laser in the mouse middle ear
      ...n F. Carbajal,1 Xi Chen,1 John S. Oghalai,2 and Brian E. Applegate1,* 1Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA 2Department of Otolaryngology—Head and Neck Surgery, ...
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    13. Method And Apparatus For Examining Inner Ear

      Method And Apparatus For Examining Inner Ear
      An apparatus, for examining an inner ear is provided. An endoscope is provided, comprising a wave guide and an end piece comprising an end window to be placed a first distance from an inner ear, wherein the waveguide focuses light to create a focal plane the first distance from the end window. An optical coherence tomography (OCT) system is connected to a second end of the wave guide and comprises ...
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    14. Biophysical Mechanisms Underlying Hearing Loss Associated with a Shortened Tectorial Membrane

      Biophysical Mechanisms Underlying Hearing Loss Associated with a Shortened Tectorial Membrane
      The tectorial membrane (TM) connects to the stereociliary bundles of outer hair cells (OHCs). Herein, we summarize key experimental data and modeling analyses that describe how biophysical alterations to these connections underlie hearing loss. The heterozygous C1509G mutation in alpha tectorin produces partial congenital hearing loss that progresses in humans. We engineered this mutation in mice, and histology revealed that the TM was shortened. DIC imaging of freshly-dissected cochlea as ...
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    15. Quantitative imaging of cochlear soft tissues in wild-type and hearing-impaired transgenic mice by spectral domain optical coherence tomography

      Quantitative imaging of cochlear soft tissues in wild-type and hearing-impaired transgenic mice by spectral domain optical coherence tomography
      ...ing Citation Simon S. Gao, Anping Xia, Tao Yuan, Patrick D. Raphael, Ryan L. Shelton, Brian E. Applegate, and John S. Oghalai, "Quantitative imaging of cochlear soft tissues in wild-type and hearing-impaired transgenic m...
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  2. Organizations in the News

    1. (12 articles) Stanford University
    2. (5 articles) Rice University
    3. (3 articles) UCLA
    4. (2 articles) University of Southern California
    5. (2 articles) Baylor College of Medicine
    6. (1 articles) World Health Organization
    7. (1 articles) Harvard University
  3. People in the News

    1. (19 articles) Brian E. Applegate
    2. (2 articles) Audrey K. Bowden
    3. (2 articles) Hee Yoon Lee
    4. (2 articles) Wihan Kim
    5. (2 articles) Ryan L. Shelton