When does the term "crossover" apply in audiological testing?

The term "crossover" in audiological testing specifically refers to the phenomenon where sound presented to one ear is perceived by the other ear. This can occur in cases where the sound is loud enough to bypass the masked ear and stimulate the cochlea of the opposite ear.

Crossover is particularly relevant in testing with a masked ear, as it can lead to inaccurate threshold measurements if not appropriately managed. For example, if a tone is presented to the test ear and the intensity is sufficiently high, it may "cross over" through bone conduction, thus being detected by the non-test ear. This can lead to the perception of sound in the opposite ear without the intention of the test.

This concept is critical in ensuring that audiologists can accurately assess the hearing ability of each ear independently and take necessary precautions, such as employing masking techniques, to avoid crossover interference during testing.