TY - JOUR
T1 - Longitudinal changes in dynamic characteristics of neonatal external and middle ears
AU - Kanka, Nattikan
AU - Murakoshi, Michio
AU - Hamanishi, Shinji
AU - Kakuta, Risako
AU - Matsutani, Sachiko
AU - Kobayashi, Toshimitsu
AU - Wada, Hiroshi
N1 - Funding Information:
The authors are grateful to the nurses and other personnel of the Japanese Red Cross Sendai Hospital, Sendai, Japan, for their cooperation. This work was supported by JSPS KAKENHI Grant Number JP16K11194 to H.W, and by a grant from the TERUMO FOUNDATION for LIFE SCIENCES and ARTS and a grant from the MIKIYA Science And Technology Foundation to M.M.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/7
Y1 - 2020/7
N2 - Objectives: Neonates have smaller and less mature ears than adults. Developmental changes in structure and function continually occur after birth and may affect the diagnostic results obtained by audiometric assessment instrumentation, such as tympanometry and otoacoustic emission. In the present study, we investigated longitudinal changes in external and middle ear dynamic characteristics by performing sweep frequency impedance (SFI) tests. Methods: SFI tests were longitudinally performed on healthy Japanese neonates (1 female and 1 male) from birth to 3 and 5 months, respectively. A sound of sweeping sinusoidal frequency, ranging from 0.1 kHz to 2 kHz, was presented to the ear canal at 50-daPa intervals of static pressure from +200 to −200 daPa. Test results were expressed a curve showing the sound pressure level (SPL) relative to probe tone frequency, called SPL curve. Results: The first fluctuation in resonance frequency (RF1) and SPL (ΔSPL1), related to the external ear, showed significant developmental changes as chronological age increased; that is, RF1 and ΔSPL1 were respectively increased and decreased and thereafter became unmeasurable by 5 months of age. In contrast, the second fluctuation in resonance frequency (RF2) and SPL (ΔSPL2), related to the middle ear, did not show significant changes over the measurement period. Conclusions: The present results suggest that the dynamic characteristics of the external ear canal wall changed with increases in chronological age; the resonance of the wall at about 0.3 kHz at birth tended to increase to about 0.7 kHz and to be unmeasurable by 5 months of age, while those of the middle ear did not significantly changed. These results showing how neonatal-ear dynamics changes with chronological age may be an important key in further hearing research and the development of hearing devices and diagnostic tools suitable for neonates.
AB - Objectives: Neonates have smaller and less mature ears than adults. Developmental changes in structure and function continually occur after birth and may affect the diagnostic results obtained by audiometric assessment instrumentation, such as tympanometry and otoacoustic emission. In the present study, we investigated longitudinal changes in external and middle ear dynamic characteristics by performing sweep frequency impedance (SFI) tests. Methods: SFI tests were longitudinally performed on healthy Japanese neonates (1 female and 1 male) from birth to 3 and 5 months, respectively. A sound of sweeping sinusoidal frequency, ranging from 0.1 kHz to 2 kHz, was presented to the ear canal at 50-daPa intervals of static pressure from +200 to −200 daPa. Test results were expressed a curve showing the sound pressure level (SPL) relative to probe tone frequency, called SPL curve. Results: The first fluctuation in resonance frequency (RF1) and SPL (ΔSPL1), related to the external ear, showed significant developmental changes as chronological age increased; that is, RF1 and ΔSPL1 were respectively increased and decreased and thereafter became unmeasurable by 5 months of age. In contrast, the second fluctuation in resonance frequency (RF2) and SPL (ΔSPL2), related to the middle ear, did not show significant changes over the measurement period. Conclusions: The present results suggest that the dynamic characteristics of the external ear canal wall changed with increases in chronological age; the resonance of the wall at about 0.3 kHz at birth tended to increase to about 0.7 kHz and to be unmeasurable by 5 months of age, while those of the middle ear did not significantly changed. These results showing how neonatal-ear dynamics changes with chronological age may be an important key in further hearing research and the development of hearing devices and diagnostic tools suitable for neonates.
KW - Dynamic characteristics
KW - Longitudinal change
KW - Neonatal ear
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U2 - 10.1016/j.ijporl.2020.110061
DO - 10.1016/j.ijporl.2020.110061
M3 - Article
C2 - 32387706
AN - SCOPUS:85084209447
SN - 0165-5876
VL - 134
JO - International Journal of Pediatric Otorhinolaryngology
JF - International Journal of Pediatric Otorhinolaryngology
M1 - 110061
ER -