KUKU

KU ScholarWorks

  • myKU
  • Email
  • Enroll & Pay
  • KU Directory
    • Login
    View Item 
    •   KU ScholarWorks
    • Dissertations and Theses
    • Dissertations
    • View Item
    •   KU ScholarWorks
    • Dissertations and Theses
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    The Effect of Activating the Medial Olivocochlear Fibers on Cochlear Distortions in Humans

    Thumbnail
    View/Open
    Jamos_ku_0099D_16005_DATA_1.pdf (1.304Mb)
    Issue Date
    2018-05-31
    Author
    Jamos, Abdulah Mohammad
    Publisher
    University of Kansas
    Format
    83 pages
    Type
    Dissertation
    Degree Level
    Ph.D.
    Discipline
    Hearing and Speech
    Rights
    Copyright held by the author.
    Metadata
    Show full item record
    Abstract
    The function of the medial olivocochlear (MOC) fibers has been investigated extensively in animals, and far less in humans. A possible function of the MOC efferents is protection against loud sounds. The aim of this study is to investigate a potential tool for evaluating the MOC reflex clinically in humans. Cochlear microphonic (CM) and the associated distortions were measured while activating the MOC fibers for an extended period of time. CM was recorded in 16 normal hearing young adults using 500 Hz toneburst at 80 dB nHL. Recording of CM was conducted every three minutes for a time-block of 18-minutes. Four total 18-minute time-blocks were recorded, two without contralateral broadband noise (CBBN) [condition (1)] and two with 50 dB SPL CBBN [condition (2)]. The CM responses were subjected to fast-Fourier transform to obtain the amplitude of the primary frequency (F1=500Hz), and the second (2F1=1000Hz) and the third (3F1=1500Hz) harmonics. A repeated-measures ANOVA was completed on the amplitude of F1, 2F1, and 3F1, and post-hoc analysis was utilized using LSD. There is approximately 21% increase in the F1 amplitude as a result of presenting CBBN, which is significant (p<0.01). There is a significant change in 2F1 (p<0.01) and 3F1 (p<0.01) amplitudes as a result of presenting the CBBN. The current study shows that the activation of the MOC fibers results in enhancement of the CM response. Furthermore, the results show that activation of the MOC fibers causes modulation of 2F1 and 3F1 of the CM response. The resulting changes of the CM distortions are in agreement with the proposed model of adjusting the operating point of the cochlear amplifier as a result of activating the MOC fibers. These results support the use of CM measurement as an objective measure for evaluating the MOC reflex clinically.
    URI
    http://hdl.handle.net/1808/27885
    Collections
    • Dissertations [4474]
    • Speech-Language-Hearing Dissertations and Theses [75]

    Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.


    We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.


    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    Browse

    All of KU ScholarWorksCommunities & CollectionsThis Collection

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    The University of Kansas
      Contact KU ScholarWorks
    Lawrence, KS | Maps
     
    • Academics
    • Admission
    • Alumni
    • Athletics
    • Campuses
    • Giving
    • Jobs

    The University of Kansas prohibits discrimination on the basis of race, color, ethnicity, religion, sex, national origin, age, ancestry, disability, status as a veteran, sexual orientation, marital status, parental status, gender identity, gender expression and genetic information in the University’s programs and activities. The following person has been designated to handle inquiries regarding the non-discrimination policies: Director of the Office of Institutional Opportunity and Access, IOA@ku.edu, 1246 W. Campus Road, Room 153A, Lawrence, KS, 66045, (785)864-6414, 711 TTY.

     Contact KU
    Lawrence, KS | Maps