A preliminary study of auditory mismatch response on the day of cochlear implant activation in children with hearing aids prior implantation

P-MMR and LDN beside MMN as Speech-evoked Neural Markers in Children with Cochlear Implants: A Review

This review mainly explores less-reported neural markers to speech-evoked contrasts in children with cochlear implants (CI). Databases and electronic journals were searched with keywords of "mismatch responses" AND "positive mismatch response" (p-MMR) AND "late discriminate negativity" (LDN). P-MMR likely is as a measurement of brain immaturity in CI children while the developmental trajectories of LDN remain unexplained in older CI children. In CI children, there is a p-MMR-MMN-LDN sequence to speech stimuli developmentally. Whereas these aforementioned neural responses anticipate developmental changes in CI groups, it is still uncertain about the cutoff age for disappearance of p-MMR and LDN.

The development of hearing in prelingually deaf children with white matter changes in the first year after cochlear implantation

Background: The development of hearing and plasticity of brain after cochlear implantation (CI) for prelingually deaf children with white matter changes (group A) is unclear.Objective: To investigate the development of hearing for children in group A during 1 year after CI activation, compared with non-complicated peers (group B).Materials and methods: Twenty-one and 22 children (average age is about 5 years old) were included in groups A and B, respectively. Questionnaires were used to assess the hearing ability at pre-CI, 1, 6 and 12 months after CI activation (called Mpre, M1, M6, M12 for short). In addition, MMRs to pure tones were investigated at the same three time points after CI.Results: There is no significant difference in scores on questionnaires, MMR incidence, latency or amplitude between children in two groups. Scores on questionnaires showed a significant progressive improvement in two groups during the first year after CI. Furthermore, MMR incidence at M6 was significantly higher than that at M1, and MMR latency at M12 was significantly shorter than that at M1.Conclusions and significance: Prelingually deaf children with white matter changes achieved rapid development and comparable outcomes with CI peers over the first year after CI.

Behavioral and electrophysiological investigation of hearing and speech outcomes in pre-linguistic deaf children with white matter changes after cochlear implantation

Background: There are some debates regarding the benefit from cochlear implantation (CI) for prelingually deaf children with white matter changes.Objective: To assess the hearing and speech outcomes of prelingually deaf children with white matter changes (group A), and those with complete deafness (group B), at 2 years after CI.Material and Methods: Study 1 included 32 and 34 children in group A and B, respectively. The Categories of Auditory Performance (CAP) and Speech Intelligibility Rate (SIR) were used to assess the performance on hearing and speech. Study 2 included eight children with white matter changes and eight with complete deafness at 2 years post-CI, and nine normal-hearing peers. The mismatch response (MMR) to the stimulus pair 'ba'/'pa' was investigated.Results: There was no significant difference on CAP or SIR scores between the children in group A and B. All children with white matter changes showed MMRs to Mandarin consonants at 2 years post-CI. And there was no significant difference on the incidence, the latency or amplitude of MMR among three groups.Conclusions and significance: Most prelingually deaf children with white matter changes got good outcomes from CI. CI is not a contraindication for most individuals with white matter changes.