What does the term "over-masking" refer to in audiology?

Over-masking refers to a phenomenon that occurs when excessive or inappropriate levels of masking noise are introduced into a hearing test, leading to invalid results. In audiology, masking is utilized to isolate the ear being tested to ensure accurate threshold assessments, especially in cases of unilateral hearing loss.

When the masking noise is set too high, it can cross over to the non-test ear, thus interfering with the pure tone signals and making it difficult to determine the true auditory threshold of the test ear. This results in the participant perceiving a sound in the masked ear that isn't genuinely heard, consequently producing inaccurately elevated threshold results.

Understanding over-masking is critical for audiologists, as it emphasizes the need for precise calculations and measurements to ensure that the masking level is adequate but not excessive. This ensures that the testing remains valid and reflects the true hearing capabilities of the individual being assessed.