Early Vocal Development in Young Children with Simultaneous Bilateral Cochlear Implants: A Short-term Longitudinal Acoustic Analysis of Spontaneous Speech.

BACKGROUND

Children with cochlear implants (CIs) often exhibit distinct vocal characteristics because of early auditory deprivation and altered auditory feedback. Although segmental-level speech outcomes in the CI population have been extensively investigated, few longitudinal studies have examined voice development by using ecologically valid spontaneous speech samples, particularly during the critical early period of language acquisition. This preliminary study aimed to investigate early longitudinal changes in pitch, intensity, and voice quality in the spontaneous speech of young children with simultaneous bilateral CIs and compare them with those of age-matched children with typical hearing (TH).

METHOD: The participants were six children who have prelingual deafness and received simultaneous bilateral CIs and eight age-matched children with TH. Spontaneous speech samples were collected during parent-child free-play interactions at three time points: T1 (∼21 months), T2 (∼28 months), and T3 (∼34 months). Intentional vocalizations (eg, speech-like vocal play, canonical babbling, and real words) were acoustically analyzed in terms of pitch, intensity, and voice quality parameters by using the KayPENTAX Real-Time Pitch and Analysis of Dysphonia in Speech and Voice systems.

RESULTS

Both groups exhibited developmental trajectories characterized by the increase in pitch range and spectral ratio and the decrease in minimum pitch and intensity. Notably, children with CIs demonstrated a steeper increase in pitch range and greater variability in intensity over time; these findings suggested that their vocal motor control was continuously adjusting. Although group differences in pitch and voice quality decreased across time points, a persistently lower minimum intensity in the CI group might indicate a continued difficulty in modulating soft phonation.

CONCLUSION

Despite persistent group differences in certain acoustic measures, children with simultaneous bilateral CIs exhibited developmental patterns that were increasingly consistent with those of their TH peers. Therefore, early bilateral implantation might facilitate more age-appropriate vocal development in young children with CIs.