| The breaking of cochlear scaling symmetry in human newborns and adults. | |
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MedLine Citation:
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PMID: 21568413 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Scaling symmetry appears to be a fundamental property of the cochlea as evidenced by invariant distortion product otoacoustic emission (DPOAE) phase above ∼1-1.5 kHz when using frequency-scaled stimuli. Below this frequency demarcation, phase steepens. Cochlear scaling and its breaking have been described in the adult cochlea but have not been studied in newborns. It is not clear whether immaturities in cochlear mechanics exist at birth in the human neonate. In this study, DPOAE phase was recorded with a swept-tone protocol in three, octave-wide segments from 0.5 to 4 kHz. The lowest-frequency octave was targeted with increased signal averaging to enhance signal-to-noise ratio (SNR) and focus on the apical half of the newborn cochlea where breaks from scaling have been observed. The results show: (1) the ear canal DPOAE phase was dominated by the distortion-source component in the low frequencies; thus, the reflection component cannot explain the steeper slope of phase; (2) DPOAE phase-frequency functions from adults and infants showed an unambiguous discontinuity around 1.4 and 1 kHz when described using two- and three-segment fits, respectively, and (3) newborns had a significantly steeper slope of phase in the low-frequency portion of the function which may suggest residual immaturities in the apical half of the newborn cochlea. |
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Authors:
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Carolina Abdala; Sumitrajit Dhar; Srikanta Mishra |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of the Acoustical Society of America Volume: 129 ISSN: 1520-8524 ISO Abbreviation: J. Acoust. Soc. Am. Publication Date: 2011 May |
Date Detail:
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Created Date: 2011-05-16 Completed Date: 2011-09-12 Revised Date: 2012-05-01 |
Medline Journal Info:
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Nlm Unique ID: 7503051 Medline TA: J Acoust Soc Am Country: United States |
Other Details:
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Languages: eng Pagination: 3104-14 Citation Subset: IM |
Affiliation:
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Division of Communication and Auditory Neuroscience, House Research Institute, 2100 West Third Street, Los Angeles, California 90057, USA. cabdala@hei.org |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Cochlea / growth & development*, physiology, ultrastructure Female Humans Infant, Newborn / physiology* Male Models, Biological Otoacoustic Emissions, Spontaneous / physiology Perceptual Distortion / physiology |
| Grant Support | |
ID/Acronym/Agency:
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R01 DC03552/DC/NIDCD NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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