Temporal mechanisms underlying recovery from forward masking in multielectrode-implant listeners

This paper describes a detailed study of recovery from forward masking in six users of the Nucleus-22 cochlear implant with a range of performance in speech-recognition tests. Recovery from a 300-ms-long pulse train presented at 1000 pps was found to be fastest in the poorer performers. The shape of the recovery function was found to be most strongly influenced by masker duration, suggesting that temporal integration plays a prominent role in recovery from forward masking. The recovery functions are reasonably well described by a sum of two exponentially decaying processes. Their relative weights depend on the amount of temporal integration occurring during the masker, and show strong intersubject variability. Nonmonotonicities sometimes observed in the recovery functions may be accounted for by considering the influence of neural adaptation. (C) 1999 Acoustical Society of America. [S0001-4966(99)00403-8].