Post-lingual deaf adult cochlear implant users' speech and voice characteristics: cochlear implant turned-on versus...

A time-period of turning off cochlear implant (CI) might affect the speech and voice features of the CI users due to loss of auditory feedback monitoring.

To evaluate Persian-speaking CI users' speech and voice parameters in a device-on/off experiment.

Forty-eight Persian-speaking adults with post-linguistic deafness who had received a unilateral CI and 50 normally-hearing counterparts were recruited. All CI users had to fulfill three phases of speech sampling, including the device-on, device-off (a 5-hourly period), and once again device-on phase. Their Fundamental frequency, Jitter, Shimmer, Harmonics-to-noise ratio, hyper-nasality score, and the percentage of speech intelligibility were assessed for both groups.

The findings revealed that the CI-on/off conditions significantly changed cochlear implanted participants' F0, Shimmer, HNR, and hyper-nasality values. However, no statistical differences were observed in Jitter and the percentage of speech intelligibility between the CI and control groups.

A short-term auditory deprivation in CI recipients could degrade the speech and voice quality in CI users, so that could change the quality of their speech resonance into hyper-nasality. However, when the CIs were turned on again, the quality of their speech and voice returned to normal-sounding.