Contralateral suppression of transient evoked otoacoustic emissions in adults: A normative study.

Only 40 ears from 10 females and 10 males aged 18 to 25 years were tested, so the norms cannot be assumed to apply to children, older adults, or larger populations. The participants were selected for normal hearing, normal middle-ear function, present acoustic reflexes, and normal transient evoked otoacoustic emissions, so the study says nothing about people with hearing loss, middle-ear disease, or suspected efferent pathway problems. The TEOAE-CAS module was newly developed and not commercially available, and the contralateral stimulus was a click rather than white noise, so values may not transfer to other devices or protocols. The study was a small pilot normative study, not a diagnostic accuracy study, so it does not show that contralateral suppression can identify cochlear or efferent pathology. Test-retest reliability was checked only within the same session, with no more than 5 minutes between recordings, so stability over days or visits is not shown. Mean suppression was 0.8 dB, lower than the 1 to 4 dB reported in earlier literature, and the authors note that stimulus parameters and equipment can change normative values.

The supplied text does not report funding or conflicts of interest. It states that the TEOAE-CAS module used was a newly developed PATH MEDICAL device that was not commercially available.

Do not use 0.8 dB as a clinical cutoff or assume this test diagnoses efferent pathway problems. The values come from 40 ears of young adults with normal hearing, tested with one newly developed module, and the study did not test patients.