Abstract
In this study, we investigated the effects of time-compressed speech for cochlear implant (CI) users and normal hearing subjects (NHs), and also determined the effectiveness of pauses inserted in speech passages clips.
Our subjects comprised 13 CI subjects using the Nucleus CI-24 system with the ACE processing strategy, and 10 age-matched and NH adults serving as control subjects.
As for the experimental stimuli, sentence test materials were time-compressed to ratios of 0.75 and 0.5 relative to the natural speaking rate, using sound editing software. Furthermore, these time-compressed speech clips were restored to 100% of the original duration by inserting silences at syntactic boundaries and random points in the passage clip. Subjects were instructed to listen to each passage and to recall the sentences aloud as much as possible.
Results showed that speech perception scores decreased as the speech rate increased in both CI users and NHs, the tendency being more pronounced in the CI users than in the NHs. In the CI users, time restoration at syntactic points improved the recall performance only for 0.75 time-compressed speech.
We suggest that it is important to insert pauses at semantically appropriate points during rapid speech for CI users.
