Forward masking in patients with cochlear implants.

Forward masking was measured in 12 patients with cochlear implants. The amount of masking (in microamps) decreased linearly as a function of the logarithm of the signal delay from masker offset. Normalized forward-masking recovery functions for cochlear implants were similar to normalized functions of normal-hearing listeners, indicating that the mechanism of psychophysical forward masking is retrocochlear. These results indicate that the logarithm of acoustic amplitude should be mapped to microamps to produce normal forward masking in implanted patients. Despite the fact that the forward-masking recovery functions were similar across all patients, their performance with their speech processor varied widely.