Document Detail

Ear-canal impedance and reflection coefficient in human infants and adults.
MedLine Citation:
PMID:  8270739     Owner:  NLM     Status:  MEDLINE    
The ear-canal impedance and reflection coefficient were measured in an adult group and in groups of infants of age 1, 3, 6, 12, and 24 months over frequency range 125-10,700 Hz. The development of the external ear canal and middle ear strongly affect input impedance and reflection coefficient responses, and this development is not yet complete at age 24 months. Contributing factors include growth of the area and length of the ear canal, a resonance in the ear-canal walls of younger infants, and a probable influence of growth of the middle-ear cavities. The middle-ear compliance is lower in infants than adults, and the middle-ear resistance is higher. The power transfer into the middle ear of the infant is much less than into that of the adult. Such differences in power transfer directly influence both behavioral and physiological measurements of hearing. The difficulties of interpretation of neonatal tympanograms are shown to be a consequence of ear-canal wall vibration. Impedance and reflectance measurements in the 2-4-kHz range are recommended as a potentially useful clinical tool for circumventing these difficulties.
D H Keefe; J C Bulen; K H Arehart; E M Burns
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  94     ISSN:  0001-4966     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  1993 Nov 
Date Detail:
Created Date:  1994-02-02     Completed Date:  1994-02-02     Revised Date:  2006-12-27    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2617-38     Citation Subset:  IM    
School of Music DN-10, University of Washington, Seattle 98195.
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MeSH Terms
Acoustic Impedance Tests*
Acoustic Stimulation
Age Factors
Auditory Threshold
Ear, External / anatomy & histology,  physiology*
Ear, Middle / physiology
Hearing / physiology
Infant, Newborn
Longitudinal Studies
Speech Acoustics
Speech Perception*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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