Masking
The clinical technique of introducing a noise stimulus into the non-test ear during audiometric testing to prevent it from detecting the signal intended for the test ear, ensuring valid unilateral threshold measurements.
Full Definition
Masking is a fundamental procedural requirement in audiometry that prevents cross-hearing, whereby the sound presented to the test ear is transmitted through the skull and perceived by the non-test (contralateral) ear. Narrowband noise is used during pure-tone audiometry and speech noise during speech audiometry. The masking level must be calibrated to be sufficient to occlude the non-test ear without 'over-masking' (shifting the test-ear threshold via bone conduction). In clinical reports, editors should verify that masking conditions are stated in the methods or notes, and that masked thresholds are identified with the correct audiogram symbols (square brackets or symbols with a horizontal bar).
Usage
Usage note: Always distinguish between 'masked' and 'unmasked' thresholds when editing audiograms and reports, as unmasked thresholds in cases of asymmetric hearing loss may be clinically misleading.
In Context
- "Masking was applied to the left ear during bone-conduction testing of the right ear to eliminate the risk of cross-hearing." — Audiological test report
- "The results section did not indicate whether masking was employed during bone-conduction audiometry; the editor requested clarification." — Manuscript review