What does overmasking indicate regarding the test ear threshold?

Overmasking is a phenomenon that occurs in audiometric testing, specifically when masking noise presented to one ear (the non-test ear) is so loud that it interferes with the test signal being presented to the other ear (the test ear). This situation leads to a shift in the perceived threshold of hearing, as the masking noise effectively raises the threshold, indicating that the true threshold of the test ear is not being accurately determined.

When correct masking is applied, the strength of the masking noise is carefully adjusted to avoid impacting the test ear while preventing the non-test ear from responding to the test signal. However, overmasking indicates that the masking noise level is excessive, creating artificial perception of hearing thresholds. This distortion makes it impossible to obtain valid or reliable test results since the elevated threshold does not reflect the true auditory capabilities of the test ear.

Therefore, the phenomenon of overmasking highlights the importance of proper masking techniques in audiology to ensure accurate assessment of hearing thresholds.