Variations in the "Carhart Notch" and Overclosure After Laser-Assisted Stapedotomy in Otosclerosis
Bibliographic record
Abstract
OBJECTIVE: The hallmark of bone conduction audiometry in otosclerosis is the "Carhart notch." The mechanism for this phenomenon is still not clearly understood. The objective of this study was to describe the pattern of bone-conduction threshold responses preoperatively in patients with otosclerosis and to assess overclosure after laser-assisted stapedotomy. STUDY DESIGN: Retrospective case review. SETTING: Tertiary academic referral center. PATIENTS: One hundred twenty-two consecutive patients with sufficient audiometric follow-up who underwent CO2 laser-assisted stapedotomy were included. Their mean age was 45 +/- 12 years; 57 were men, and 65 were women. INTERVENTION: Laser-assisted stapedotomy and analysis of preoperative and postoperative audiograms. MAIN OUTCOME MEASURE: Presurgical and postsurgical bone and air conduction audiograms. RESULTS: Ninety-eight (80%) of 122 patients had a notch configuration in their preoperative audiogram. The notches were distributed as follows: 31% at 0.5 kHz, 32% at 1 kHz, and 37% at 2 kHz. A higher percentage of 0.5-kHz notches were observed in the group of 15 patients who did not achieve full air-bone gap closure. Eighty-one percent of the patients demonstrated overclosure in one or more of the frequencies between 0.5 and 4 kHz, which was maximal at 1 and 2 kHz (mean, 7.5 and 8.3 dB, respectively). CONCLUSION: It seems that the morphology of the Carhart notch is variable and is not exclusively at 2 kHz as originally described. In addition, the increased prevalence of 0.5-kHz notches in individuals with a persistent air-bone gap may be indicative of other middle ear pathology such as incus or malleus fixation.
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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 | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.002 | 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".