Cortical Processing of Vocal and Nonvocal Sounds in Cochlear-Implanted Children: An Electrophysiological Study

Electrophysiological Examination of Ambient Speech Processing in Children With Cochlear Implants

PURPOSE

This research examined the expression of cortical auditory evoked potentials in a cohort of children who received cochlear implants (CIs) for treatment of congenital deafness (n = 28) and typically hearing controls (n = 28).

METHOD

We make use of a novel electroencephalography paradigm that permits the assessment of auditory responses to ambiently presented speech and evaluates the contributions of concurrent visual stimulation on this activity.

RESULTS

Our findings show group differences in the expression of auditory sensory and perceptual event-related potential components occurring in 80- to 200-ms and 200- to 300-ms time windows, with reductions in amplitude and a greater latency difference for CI-using children. Relative to typically hearing children, current source density analysis showed muted responses to concurrent visual stimulation in CI-using children, suggesting less cortical specialization and/or reduced responsiveness to auditory information that limits the detection of the interaction between sensory systems.

CONCLUSION

These findings indicate that even in the face of early interventions, CI-using children may exhibit disruptions in the development of auditory and multisensory processing.

Changes in P1 latencies of children with normal hearing and those with cochlear implants

Background/aim

The aim of this study was to determine the age-related latency interval of P1 latencies of children with normal hearing, and to evaluate the P1 latency changes after surgery in children who underwent cochlear implantation.

Materials and methods

We evaluated 60 children with normal hearing and 16 children with cochlear implants aged 0–6 years using cortical auditory evoked potentials. P1 latencies were measured only once in the children with normal hearing, and on the postoperative first day, and the first, third, and sixth postoperative months in the children with cochlear implants.

Results

There was a statistically significant decrease in the P1 latencies as the age increased in children with normal hearing (P < 0.001). It was determined that when the external partof the cochlear implant was applied, the P1 latencies of children with cochlear implants were significantly longer than those of age-matched children with normal hearing (P < 0.001). This difference disappeared in 10 children with implants at the third and sixth months, but significant differences remained in 6 children.

Conclusion

P1 latency could be used as an objective tool to evaluate the normal development of auditory pathways, and may be helpful in the effective programming of children undergoing cochlear implantation.