Influence of bilateral cochlear implants on vocal control.

Receiving a cochlear implant (CI) can improve fundamental frequency (F0) control for deaf individuals, resulting in increased vocal pitch control. However, it is unclear whether using bilateral CIs, which often result in mismatched pitch perception between ears, will counter this benefit. To investigate this, 23 bilateral CI users were asked to produce a sustained vocalization using one CI, the other CI, both CIs, or neither. Additionally, a set of eight normal hearing participants completed the sustained vocalization task as a control group. The results indicated that F0 control is worse with both CIs compared to using the ear that yields the lowest vocal variability. The results also indicated that there was a large range of F0 variability even for the relatively stable portion of the vocalization, spanning from 6 to 46 cents. These results suggest that bilateral CIs can detrimentally affect vocal control.