Maturation of the Occlusion Effect: A Bone Conduction Auditory Steady State Response Study in Infants and Adults With Normal Hearing
Bibliographic record
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.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".