Ear selection and pediatric cochlear implants: a preliminary examination of speech production outcomes

The Best Users of Cochlear Implants

The aim of this descriptive-analytical study was to compare the categories of auditory performance (CAP) and speech intelligibility rating (SIR) in people with cochlear implants (CI) based on the implanted ear. CAP and SIR were evaluated in 184 people with CI of right (110) and left (74) ears every 6 to 24 months (6,12,18,24). The significance level was less than 0.05. People with CI in the right-ears had better mean CAP and SIR scores than the left-ears (P values6,12,18, 24= 0.001, 0.004, 0.004, 0.002, and 0.001, 0.010, 0.010, 0.006). There were the relationship between the means of language acquisition status at the time of surgery and the means of CAP and SIR scores (P values6,12,18, 24= 0.005, 0.031, 0.006, 0.019, and 0.000, 0.000, 0.000, 0.002). The highest mean SIR scores were found in people with high school education (P values6,12,18, 24= 0.000, 0.000, 0.000, 0.008). The means of CAP scores did not show a relationship with the level of education (P values6, 12, 18, 24= 0.388, 0.217, 0.297, 0.213).  Mean SIR and CAP scores were not related to gender. People who received right ear prostheses after the language learning age and have a higher level of education are the best users of cochlear implants. Compared to others who do not have these facilities, they gain more ability in auditory-speech skills. Gender, does not affect these capabilities.

Differential auditory cortical development in left and right cochlear implanted children

Unilateral aural stimulation has been shown to cause massive cortical reorganization in brain with congenital deafness, particularly during the sensitive period of brain development. However, it is unclear which side of stimulation provides most advantages for auditory development. The left hemisphere dominance of speech and linguistic processing in normal hearing adult brain has led to the assumption of functional and developmental advantages of right over left implantation, but existing evidence is controversial. To test this assumption and provide evidence for clinical choice, we examined 34 prelingually deaf children with unilateral cochlear implants using near-infrared spectroscopy. While controlling for age of implantation, residual hearing, and dominant hand, cortical processing of speech showed neither developmental progress nor influence of implantation side weeks to months after implant activation. In sharp contrast, for nonspeech (music signal vs. noise) processing, left implantation showed functional advantages over right implantation that were not yet discernable using clinical, questionnaire-based outcome measures. These findings support the notion that the right hemisphere develops earlier and is better preserved from adverse environmental influences than its left counterpart. This study thus provides, to our knowledge, the first evidence for differential influences of left and right auditory peripheral stimulation on early cortical development of the human brain.

Speech perception with simultaneous bilateral cochlear implants: Is there a unilateral predominance?

OBJECTIVES

To assess the audiological outcomes and speech performance among children with simultaneous bilateral cochlear implants (CIs).

METHODS

This was a retrospective case review of 41 patients with prelingual deafness who failed a hearing aid trial and received simultaneous bilateral CIs. Ear-specific responses in terms of pure tone average (PTA), speech reception thresholds (SRTs), and speech discrimination score (SDS) were recorded for both ears of all patients.

RESULTS

The PTA and SRT for the right and left CIs were comparable (P-value = 0.861 and P-value = 0.524, respectively). The SDS was slightly higher for the right ear, although it was not significantly different from that for the left ear (P-value = 0.375), yielding only a 2.42% difference.

CONCLUSION

We found no significant side preference in all assessment scores for children with simultaneous bilateral CIs. Therefore, we cautiously advise implanting the CI in the right ear in case of symmetrical hearing loss when other prognostic factors do not favor the left ear.

Predicting the Future: A Case Study in Prognostication

PURPOSE

Clinicians are regularly asked to make long-term prognoses. The aim of the current report was to present one systematic approach to doing so. A case example from a malpractice case involving a child fitted with a cochlear implant was presented. Implantation occurred at age 17 months (activation 1 month later), but due to a procedural error, the implant was not functional for 19 months. The problem was ultimately rectified, but the legal case hinged largely on whether the child would be able to make up for the lost time.

METHOD

A review of the literature on long-term outcomes in children with cochlear implants was conducted. Using 4 studies measuring outcomes 7-10 years later, outcomes were compared between children implanted at age 17-18 months and those implanted at age 36-37 months.

RESULTS

Analysis suggested no potential impact on nonverbal cognitive skills. However, analysis in the areas of speech perception, word comprehension, speech intelligibility, and reading suggested that after 7-10 years, this child would potentially continue to be approximately 1-2 years behind where she might otherwise have been.

CONCLUSIONS

This case illustrated the possibility of deriving a long-term prognosis using a systematic examination of the existing outcomes literature. Such an approach is consistent with our mandate to engage in evidence-based practice.

The effect of side of implantation on unilateral cochlear implant performance in patients with prelingual and postlingual sensorineural hearing loss: A systematic review

OBJECTIVE

Cerebral lateralisation of language processing leads to a right ear advantage in normal hearing subjects. The aim of this study was to present a systematic overview of the effect of implantation side on postoperative cochlear implant performance in patients with symmetrical severe to profound sensorineural hearing loss.

DATA SOURCES

PubMed, Embase and The Cochrane Library databases.

RESEARCH METHODS

Databases were searched from database inception up to 9 January 2017 for cochlear implant and side and all synonyms. Title, abstract and full-text of retrieved articles were screened for eligibility. Then, directness of evidence and risk of bias were assessed. For the included articles, study characteristics and outcome data (hearing and language development) were extracted.

RESULTS

2541 unique articles were screened, of which twenty were eligible for critical appraisal. No randomised controlled trials were identified. Twelve studies with a high directness of evidence remained for data extraction. Four of six studies including children with pre-lingual sensorineural hearing loss and four of seven studies investigating adults with postlingual sensorineural hearing loss found a right ear advantage in at least one outcome measurement related to cochlear implant performance.

CONCLUSION

The available evidence on the effect of side of implantation is of low quality, as study populations and outcome measures are heterogeneous. The majority of studies reveals evidence for a right ear advantage in prelingually deafened children as well as postlingually deafened adults. In view of the present evidence and as no left ear advantage was identified, we cautiously advise implanting the cochlear implant in the right ear when other prognostic factors do not favour the left ear and sensorineural hearing loss is symmetrical.

Single word and sentence intelligibility in children with cochlear implants

This study examined the intelligibility of speech produced by 17 children (aged 4-11 years) with cochlear implants. Stimulus items included sentences from the Beginners' Intelligibility Test (BIT) and words from the Children Speech Intelligibility Measure (CSIM). Naïve listeners responded by writing sentences heard or with two types of responses to the word recordings; open transcription (CSIM-T) and closed set multiple choice (CSIM-MC). Percentage of items understood, averaged across three naïve judges, were compared across the three measures. Additionally, scores were examined for any relationships with chronological age, age of implantation, and amount of implant experience. Strong positive correlations were observed among all three intelligibility tasks. Scores on all three tasks were found to be significantly different from each other. A significant correlation was obtained between intelligibility and amount of implant experience, but not with chronological age or age of implantation. Results suggest that judging the intelligibility of speech produced by children with cochlear implants using both single word and sentence levels would provide a better overall estimate of their intelligibility. The results also emphasize the vital role of auditory input in the development of intelligible speech.