Integrity of the auditory pathway in young children with congenital and postmeningitic deafness

Correlation of neurocognitive processing subtypes with language performance in young children with cochlear implants

OBJECTIVES

Test data were used to explore the neurocognitive processing of a group of children with cochlear implants (CIs) whose language development is below expectations.

METHODS

This cross-sectional study examines the relationship between neurocognitive processing, as assessed by the Kaufman Assessment Battery for Children-Second Edition, and verbal language standard scores, assessed using either the Comprehensive Assessment of Spoken Language or the Clinical Evaluation of Language Fundamentals in 22 school-age children with CIs. Processing scores of CI recipients with language scores below expectations were compared to those of children meeting or exceeding language expectations. Multiple linear regression estimated the associations of simultaneous and sequential processing with language scores.

RESULTS

Though simultaneous processing scores between the two groups were similar, the mean sequential processing score (91.2) in the below expectations group (n = 13) was significantly lower (P = 0.002) than that of children (n = 9) meeting expectations (110.8). After adjusting for age at implantation, a 10-point higher sequential processing score was associated with a 7.4 higher language score (P = 0.027).

DISCUSSION

Simultaneous processing capacity was at least within the average range of cognitive performance, and was not associated with language performance in children with CIs. Conversely, reduced sequential processing capacity was significantly associated with lower language scores.

CONCLUSION

Neurocognitive skills, specifically cognitive sequencing, serial ordering, and auditory-verbal memory may be targets for therapeutic intervention. Intensive cognitive and educational habilitation and in milieu intervention may improve language learning in children with CIs.

Electrically evoked amplitude modulation following response in cochlear implant candidates: comparison with auditory nerve response telemetry, subjective electrical stimulation, and speech perception

OBJECTIVE

To establish the objective, noninvasive recording of the electrically evoked amplitude modulation following response (EAMFR) for the assessment of auditory nerve function in cochlear implant candidates.

STUDY DESIGN

Prospective clinical study from 2007 to 2010.

SETTING

Cochlear Implant Programme at the Charité-Universitätsmedizin Berlin (Germany).

PATIENTS

Thirty-eight patients with severe-to-total bilateral sensorineural hearing impairment.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

The EAMFR thresholds were correlated with the mean thresholds of the intraoperative electrically evoked compound action potential (ECAP) derived by auditory nerve response telemetry and with the subjective electrical stimulation test. The intraindividual left-right similarity of the EAMFR and ECAP thresholds was investigated in 9 bilaterally implanted patients. Additionally, the correlation between auditory performance and EAMFR thresholds was investigated.

RESULTS

The EAMFR auditory nerve function test produced clear responses in all patients. The EAMFR thresholds correlated significantly with the mean ECAP thresholds (r = 0.58, p < 0.01) and the subjective electrical stimulation test (r = 0.32, p < 0.05). In the bilaterally implanted patients, there was either no side difference, or the ear with the lower preoperative EAMFR threshold also was the one with the lower intraoperative mean ECAP threshold. No correlation was found between EAMFR thresholds and postoperative speech recognition scores.

CONCLUSION

These novel results support the notion that the EAMFR auditory nerve function test is a useful objective and noninvasive tool to provide information about the responsiveness of the auditory nerve to electrical stimulation in cochlear implant candidates.

Does cause of deafness influence outcome after cochlear implantation in children?

OBJECTIVES

The objective of this study was to evaluate long-term speech perception abilities of comparable groups of postmeningitic and congenitally deaf children after cochlear implantation.

METHODS

This prospective longitudinal study comprised 46 postmeningitic deaf children and 83 congenitally deaf children with age at implantation of < or = 5.6 years. Both groups were comparable with respect to educational setting and mode of communication and included children with additional disabilities.

RESULTS

Both postmeningitic and congenitally deaf children showed significant progress after implantation. Most (73% and 77%, respectively) could understand conversation without lip-reading or use the telephone with a known speaker 5 years after implantation, whereas none could do so before implantation. At the same interval, the postmeningitic and congenitally deaf children scored a mean open-set speech perception score of 47 (range: 0-91) and 46 (range: 0-107) words per minute, respectively, on connected discourse tracking. The respective mean scores at the 3-year interval were 22 and 29 correct words per minute, respectively. None of these children could score a single correct word per minute before implantation. The progress in both groups was statistically significant. When the 2 groups were compared, there was no statistically significant difference.

CONCLUSION

Postmeningitic and congenitally deaf children showed significant improvement in their auditory receptive abilities at the 3- and 5-year intervals after cochlear implantation. There was no statistically significant difference between the outcomes of the 2 groups, suggesting that, provided that children receive an implant early, cause of deafness has little influence on outcome. Although the prevalence of other disabilities was similar in both groups, for individual children, their presence may have profound impact. The study supports the concept of implantation early in life, irrespective of the cause of deafness.

Predicting speech perception outcomes following cochlear implantation using Nottingham children's implant profile (NChIP)

BACKGROUND/OBJECTIVE

Nottingham children's implant profile (NChIP) is a systematic framework to assess deaf children before implantation taking into account not only the well-known factors (age, duration of deafness) but also family and support services, expectations, children's cognitive abilities and learning style. The aim of the present paper is to assess the predictive value of the NChIP in the long-term outcomes of implanted children.

PATIENTS

This prospective and longitudinal study involved 51 profoundly deaf children, implanted within the same paediatric cochlear implant programme. All children were pre-lingually deaf with age at onset of deafness <2 years and age at implantation <6 years. Three and 4 years following implantation all children were assessed using two measures of speech perception. No child was lost to follow-up and no child was excluded from the study for any reason.

RESULTS

The most constant predictor of the outcomes was children's learning style explaining upto 29% of the variance. Other significant predictors of the outcome were shorter duration of deafness, young age at implantation and family structure/support.

CONCLUSIONS

Intrinsic factors in children and how well they communicate with their environment are of paramount importance to the outcome following implantation. The predictive value of NChIP has been demonstrated and the most important predictors of the outcome were children's learning style, short duration of deafness, young age at implantation, and family structure/support.

Clinical uses of electrically evoked auditory nerve and brainstem responses

PURPOSE OF REVIEW

The purpose of this review is to summarize current thinking relative to clinical applications for the electrically evoked compound action potential and the electrically evoked auditory brainstem response with the focus on works published between 1998 and 2003.

RECENT FINDINGS

During the period of this review, a considerable body of research has been published describing how the electrically evoked compound action potential can be measured and how the electrically evoked compound action potential may be used in the clinical treatment of cochlear implant patients. During this same period, there has been a decline in the number of studies reporting potential clinical applications for the electrically evoked auditory brainstem response. Perhaps the strongest clinical application for the electrically evoked compound action potential today is as a tool to facilitate the process of fitting the speech processor of the cochlear implant. This is particularly important for pediatric patients who may not be able to be programmed using traditional behavioral techniques. The accuracy of these predictions is discussed in addition to the limitations of the studies reviewed.

SUMMARY

The introduction of cochlear implants with the capability of measuring the response of the auditory nerve to electrical stimulation from an intracochlear electrode has tremendous potential to impact clinical practice. Research into how best to use this information is ongoing.

Nongenetic causes of hearing loss

Nongenetic as well as genetic etiologies must be explored in the child with identified hearing loss. Graduates of the neonatal intensive care unit are at increased risk for developing hearing loss due to hypoxia, hyperbilirubinemia, very low birth weight, and ototoxic medications. Although meningitis has decreased in frequency, it is still a risk factor for hearing loss. Cytomegalovirus remains the most common congenital infection and a relatively common etiology of hearing loss, which can be progressive. Preventable causes of hearing loss include those caused by head trauma, noise, and ototoxic medications. Identification of the etiology of hearing loss can facilitate the development of a treatment and management plan.

Factors contributing to limited open-set speech perception in children who use a cochlear implant

Cochlear implants have enabled many children with severe to profound sensorineural hearing loss to develop speech perception skills. However, some children experience few gains while others develop high levels of speech perception. We identified potential factors contributing to poor performance with an implant by studying implanted children who do not develop functional speech perception. Five children were identified as developing no open-set word recognition skills after at least 2 years of implant use. This study group was compared to a randomly selected control group (n=10) and an age-matched control group (n=5). Pre-implant factors were examined using a Graded Profile Analysis and post-implant factors were assessed in a retrospective chart review. A greater number of pre-implant concerns were raised in the study group than in randomized controls (P<0.01). Chronological age and duration of deafness were pre-implant concerns in all study group subjects. A greater number of post-implant concerns were found in the study group than in randomly selected controls (P<0.005). We conclude that while appropriate selection of candidates for cochlear implantation is important in predicting speech perception outcomes, post-implant follow-up is also essential and must include regular monitoring of equipment, monitoring of stimulation levels with use of objective measures of stimulation levels if necessary, and consistent habilitation.

The prognostic value of promontory electric auditory brain stem response in pediatric cochlear implantation

OBJECTIVE

To test the hypothesis that children with clear promontory electrically evoked auditory brain stem responses (prom-EABRs) would outperform, after cochlear implantation, children who had no prom-EABR preoperatively.

DESIGN

A prospective study was undertaken on 47 implanted children assigning them to two groups (group A: 35 children with a clear wave e-V in the preoperative prom-EABR and group B: 12 children with no prom-EABR). Speech perception and speech intelligibility were assessed annually up to 3 yr after implantation with the IOWA sentence test (level A and level B), Connected Discourse Tracking, Categories of Auditory Performance, and Speech Intelligibility Rating. t-test and Mann-Whitney U test were used to compare the above outcome measures in the two groups.

RESULTS

There was no statistically significant difference between the two groups on any of the outcome measures at any interval. Moreover, the small differences observed showed no consistent trend toward either group of children. Further analysis revealed that the outcomes have not been affected by possible confounding factors (age at implantation, duration of deafness, preoperative unaided pure-tone thresholds, and number of inserted electrodes).

CONCLUSIONS

The results suggest that children with no prom-EABR performed at levels comparable with children who had clear promontory responses preoperatively. The prognostic value of prom-EABR is limited and absence of a prom-EABR is not, by itself, a contraindication for cochlear implantation. However, in selected cases (congenital malformations, cochlear nerve dysplasia or suspected aplasia, narrow internal auditory canal, etc.) the presence of a prom-EABR is a positive finding in the assessment of candidates for cochlear implantation as it confirms the existence of intact auditory neurones.