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Maturation of the occlusion effect: a bone conduction auditory steady state response study in infants and adults with normal hearing.
Ear Hear. 2011 Nov-Dec; 32(6):708-19.EH

Abstract

OBJECTIVE

The aim of this study was to investigate the maturational time course of the occlusion effect in infants with normal hearing. The objectives were (i) to investigate the occlusion effect in a larger group of young infants, (ii) to determine whether the occlusion effect is seen in bone conduction auditory steady state responses (ASSRs) for older infants, and (iii) to investigate the mechanisms that underlie bone conduction hearing in unoccluded and occluded ears in infants by measuring sound pressure in the ear canal.

DESIGN

Experiments 1A and 1B: The SPL in the ear canal to 500, 1000, and 2000 Hz bone-conducted pure tones were compared in 22 young infants (0-7 mo), 10 older infants (10-22 mo), and 34 adults, all with normal hearing, for unoccluded and occluded ears. Experiment 2: Bone conduction behavioral thresholds in 17 adults were compared for unoccluded and occluded ears at 500, 1000, 2000, and 4000 Hz. Experiment 3: Bone conduction ASSR thresholds and amplitudes were compared in 22 young infants, 10 older infants, and 20 adults for an unoccluded and occluded test ear. Stimuli were bone-conducted amplitude/frequency-modulated tones presented simultaneously at 500, 1000, 2000, and 4000 Hz.

RESULTS

There were significant increases in sound pressure in the ear canal for stimuli presented at 40 dB HL when ears were occluded at 500 and 1000 Hz for all age groups. Infants showed the largest increases in SPL at 500 and 1000 Hz (5-8 dB > adults). Young infants showed no significant decreases in ASSR thresholds (2-6 dB) and amplitudes (0-10 nV) across frequency with occlusion; however, a significant number of infants had an occlusion effect at 500 Hz. Older infants showed a nonsignificant decrease in ASSR thresholds with occlusion (8 dB), a significant increase in ASSR amplitudes at 1000 Hz (6-21 nV), and a significant number of infants with an occlusion effect at 1000 Hz. Adult behavioral thresholds decreased significantly when ears were occluded at 500 and 1000 Hz; for ASSRs, thresholds also decreased (6-7 dB) and amplitudes increased (3-11 nV) at both 500 and 1000 Hz, but the mean trends and statistical findings were not in agreement in all cases. A significant number of adult subjects had an occlusion effect at 500 and 1000 Hz for both behavioral and ASSR thresholds.

CONCLUSIONS

Our findings suggest that the occlusion effect for ASSR thresholds in young infants is small but emerging at 500 Hz but negligible at 1000 Hz and that the occlusion effect in older infants is emerging at both 500 and 1000 Hz. The clinical implications of these findings are that it is appropriate to conduct bone conduction testing on young infants without compensating for an occlusion effect; however, for older infants, it is prudent to remove insert earphones during bone conduction testing. For both young and older infants, occluding the ear canal increases the sound pressure near the tympanic membrane; however, this pathway appears to contribute less to bone conduction hearing when ears are occluded compared with adults as measured by ASSRs.

Authors+Show Affiliations

School of Audiology and Speech Sciences, The University of British Columbia, Vancouver, British Columbia, Canada. ssmall@audiospeech.ubc.caNo affiliation info available

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Validation Study

Language

eng

PubMed ID

21617531

Citation

Small, Susan A., and Ning Hu. "Maturation of the Occlusion Effect: a Bone Conduction Auditory Steady State Response Study in Infants and Adults With Normal Hearing." Ear and Hearing, vol. 32, no. 6, 2011, pp. 708-19.
Small SA, Hu N. Maturation of the occlusion effect: a bone conduction auditory steady state response study in infants and adults with normal hearing. Ear Hear. 2011;32(6):708-19.
Small, S. A., & Hu, N. (2011). Maturation of the occlusion effect: a bone conduction auditory steady state response study in infants and adults with normal hearing. Ear and Hearing, 32(6), 708-19. https://doi.org/10.1097/AUD.0b013e31821de1b0
Small SA, Hu N. Maturation of the Occlusion Effect: a Bone Conduction Auditory Steady State Response Study in Infants and Adults With Normal Hearing. Ear Hear. 2011 Nov-Dec;32(6):708-19. PubMed PMID: 21617531.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Maturation of the occlusion effect: a bone conduction auditory steady state response study in infants and adults with normal hearing. AU - Small,Susan A, AU - Hu,Ning, PY - 2011/5/28/entrez PY - 2011/5/28/pubmed PY - 2012/3/1/medline SP - 708 EP - 19 JF - Ear and hearing JO - Ear Hear VL - 32 IS - 6 N2 - OBJECTIVE: The aim of this study was to investigate the maturational time course of the occlusion effect in infants with normal hearing. The objectives were (i) to investigate the occlusion effect in a larger group of young infants, (ii) to determine whether the occlusion effect is seen in bone conduction auditory steady state responses (ASSRs) for older infants, and (iii) to investigate the mechanisms that underlie bone conduction hearing in unoccluded and occluded ears in infants by measuring sound pressure in the ear canal. DESIGN: Experiments 1A and 1B: The SPL in the ear canal to 500, 1000, and 2000 Hz bone-conducted pure tones were compared in 22 young infants (0-7 mo), 10 older infants (10-22 mo), and 34 adults, all with normal hearing, for unoccluded and occluded ears. Experiment 2: Bone conduction behavioral thresholds in 17 adults were compared for unoccluded and occluded ears at 500, 1000, 2000, and 4000 Hz. Experiment 3: Bone conduction ASSR thresholds and amplitudes were compared in 22 young infants, 10 older infants, and 20 adults for an unoccluded and occluded test ear. Stimuli were bone-conducted amplitude/frequency-modulated tones presented simultaneously at 500, 1000, 2000, and 4000 Hz. RESULTS: There were significant increases in sound pressure in the ear canal for stimuli presented at 40 dB HL when ears were occluded at 500 and 1000 Hz for all age groups. Infants showed the largest increases in SPL at 500 and 1000 Hz (5-8 dB > adults). Young infants showed no significant decreases in ASSR thresholds (2-6 dB) and amplitudes (0-10 nV) across frequency with occlusion; however, a significant number of infants had an occlusion effect at 500 Hz. Older infants showed a nonsignificant decrease in ASSR thresholds with occlusion (8 dB), a significant increase in ASSR amplitudes at 1000 Hz (6-21 nV), and a significant number of infants with an occlusion effect at 1000 Hz. Adult behavioral thresholds decreased significantly when ears were occluded at 500 and 1000 Hz; for ASSRs, thresholds also decreased (6-7 dB) and amplitudes increased (3-11 nV) at both 500 and 1000 Hz, but the mean trends and statistical findings were not in agreement in all cases. A significant number of adult subjects had an occlusion effect at 500 and 1000 Hz for both behavioral and ASSR thresholds. CONCLUSIONS: Our findings suggest that the occlusion effect for ASSR thresholds in young infants is small but emerging at 500 Hz but negligible at 1000 Hz and that the occlusion effect in older infants is emerging at both 500 and 1000 Hz. The clinical implications of these findings are that it is appropriate to conduct bone conduction testing on young infants without compensating for an occlusion effect; however, for older infants, it is prudent to remove insert earphones during bone conduction testing. For both young and older infants, occluding the ear canal increases the sound pressure near the tympanic membrane; however, this pathway appears to contribute less to bone conduction hearing when ears are occluded compared with adults as measured by ASSRs. SN - 1538-4667 UR - https://www.unboundmedicine.com/medline/citation/21617531/Maturation_of_the_occlusion_effect:_a_bone_conduction_auditory_steady_state_response_study_in_infants_and_adults_with_normal_hearing_ L2 - https://doi.org/10.1097/AUD.0b013e31821de1b0 DB - PRIME DP - Unbound Medicine ER -