Auditory temporal resolution and open speech recognition in cochlear implant recipients.

The recognition of speech events depends, among other factors, on the resolution function. The present study was conducted to evaluate the auditory temporal resolution function in cochlear implant (CI) subjects by a gap detection threshold (GDT) test. Fourteen postlingual deaf subjects who used the Nucleus 22 Channel CI system participated in the study. They were divided into two subgroups: (1) six patients who did not achieve a significant open speech recognition score; and (2) eight patients who obtained different levels of open speech recognition ability (OSRA). Gap detection thresholds were found for six noise burst durations: 85, 65, 52, 36, 25 and 10 msec. Absolute values of GDT in the CI group were longer compared with those obtained from normal-hearing subjects. The CI values varied in consistence with burst duration; namely, as burst duration decreased, GD increased. This trend was found in CI recipients with OSRA only. Examination of the relationship between GDT and OSRA indicated that the majority of CI recipients who had OSRA showed lower GDT.