Absorbance Measurements From Normal-hearing Ears in the National Health and Nutrition Examination Survey, 2015-2016 and 2017-2020.
Jiayi Sun, Nicholas J Horton, Susan E Voss
PMID 36991532WHAT IT FOUND
Absorbance and impedance angle measurements from normal-hearing ears are consistent across race, sex, and ear side, with only small age-related differences.
These wideband acoustic immittance norms are suitable for clinical use, though 20% of measurements were excluded due to leaks or errors.
Key findings
01Group differences in absorbance and impedance angle across race, sex, and ear side were minimal, while age cohort showed the largest variations.
02Measurements from trained professionals in a community setting matched those from laboratory studies, supporting the reliability of these norms.
03Twenty percent of normal-hearing ears were excluded from the final analysis because measurements were out of range or showed probable acoustic leaks.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study only included ears that met criteria for normal hearing, so these norms do not apply to patients with middle ear pathology or hearing loss. Twenty percent of measurements from normal-hearing ears were excluded due to technical issues like leaks or calibration errors, indicating that data quality control is a significant challenge in community settings. The data selection criteria used to identify leaks were less stringent than previous laboratory standards because of differences in the measurement instrument's frequency range. Impedance magnitude data were not saved by NHANES, so the researchers could not check for probe placement errors that might affect this specific measure.
Declared interests
The study was supported by the National Institutes of Health. The authors declared no other conflicts of interest.
The easy way to misread this
Do not assume that statistically significant differences between demographic groups mean those groups require different clinical norms. The authors state that most observed differences are far smaller than the natural variability in the sample and are likely clinically insignificant, so applying separate norms for race or sex is probably unnecessary.