How much does central masking cause a shift in the test ear, in dB?

Central masking refers to the phenomenon where the perception of sound in one ear is affected by the introduction of sound in the opposite ear, typically during audiometric testing. This effect occurs at the level of the central auditory pathways in the brain and can lead to a shift in the threshold of hearing in the test ear when masker noise is presented to the non-test ear.

Research indicates that central masking typically results in a shift of approximately 5 dB in the test ear. This means that when masking noise is presented to the non-test ear, there is often a perceived increase in the threshold of hearing (i.e., the test ear appears to need a louder sound to be heard) by about 5 dB. Knowing this effect is vital for audiologists and hearing dispensers, as it influences how they interpret audiometric results and ensures accurate diagnosis and fitting of hearing aids.

The other provided options suggest shifts that are either too high or not generally supported by the literature related to central masking. While some discussions may mention different shifts in various contexts, the widely recognized value established in clinical practice for central masking is 5 dB, making it the most reliable choice in this scenario.