Understanding the Developmental Course of the Acoustic Properties of the Human Outer and Middle Ear Over the First 6 Months of Life by Using a Longitudinal Analysis of Power Reflectance at Ambient Pressure
Bibliographic record
Abstract
BACKGROUND: As shown by tympanometric and wideband acoustic immittance (WAI) measures, developmental changes that occur in the middle ear and the external auditory canal can affect the mechano-acoustic properties of the middle ear system during the first 2 years of life. However, these observed differences and the specific course of maturation have not been fully investigated. PURPOSE: The overall goal of the current study was to define the time course and rate at which functional maturation of the middle ear occurs in human infants through wideband acoustic immittance (WAI). It was also within the scope of this study to establish normative data to characterize acoustic properties of the normal middle ear in infants from birth to 6 mo of age. RESEARCH DESIGN: Newborns were tested longitudinally at 1-mo intervals up to 6 mo of age for a total of six visits. All babies passed transient evoked otoacoustic emission screening on each visit. Tympanograms and WAI were recorded, and the distributions of WAI patterns were analyzed as a function of age. WAI was measured across a wide range of frequencies from birth to 6 mos of age in a cohort of 31 infants. Test-retest differences for WAI were also evaluated. STUDY SAMPLE: Thirty-one newborns were recruited. DATA COLLECTION AND ANALYSIS: A repeated-measure analysis of variance was conducted to investigate whether the variations observed in power reflectance at ambient pressure across the six visits were statistically different. All significant findings were subject to Greenhouse-Geisser correction for repeated-measures sphericity and inflated type-I error. RESULTS: RESULTS showed that power reflectance increased (closer to 1) at low frequencies (<400 Hz) and decreased (closer to 0) at high frequencies (>2000 Hz) as a function of age. There was very little change in power reflectance from 600 to 1600 Hz across the first 6 mo of life. Most group changes that were observed were also consistently shown in longitudinal changes observed within individual subjects. CONCLUSIONS: The overall maturation of the middle ear can result in a lower reflectance at higher frequencies and a higher reflectance at lower frequencies. This could be explained by known changes in ear-canal and/or middle-ear structures across this time period, which could lead to changes in mass and resistance. An increase in volume in the middle-ear cavity, reduction of middle-ear debris, and overall decrease in resistive elements might be contributing to these changes. Significant differences were observed between each visit, which could warrant the use of age-specific norms when applying WAI data to infants less than 6 mo of age.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".