Gerard M. O'Donoghue

Age at Implantation: Its Importance in Pediatric Cochlear Implantation

Objective: To assess the influence of age at implantation on speech perception and speech intelligibility following pediatric cochlear implantation.

Surgical complications and their management in a series of 300 consecutive pediatric cochlear implantations.

Objective: To report the short- and long-term complications encountered in a large number of consecutive children undergoing implantation in a single center. The current study also describes the management and sequelae of each complication. Study Design: Prospective study assessing the surgical findings and complications of deaf children undergoing implantation. Setting: Pediatric tertiary referral center for cochlear implantation. Patients: The present study includes 300 consecutive children undergoing implantation, with a mean age at implantation of 5.1 years, ranging from 1.3 to 16.9 years. Of these children, 196 (65%) had congenital deafness of unknown cause. The commonest known cause was meningitis (73 of 300 [24%]) followed by congenital cytomegalovirus infection (17 of 300 [6%]). Children have been followed up regularly after implantation, typically at yearly intervals after the first year. The mean duration of follow-up at the time of the study was 4 years (range, 0.1–14 yr). Results: There were no major perioperative (within 1 d after surgery) or major early postoperative (within 1 wk after surgery) complications. In the same periods, there were 19 and 15 minor complications, respectively. These complications (e.g., eardrum perforation, hematoma, flap swelling, wound infection, temporary facial weakness) settled with conservative treatment or minor intervention. With regard to the late surgical complications (>1 wk after surgery), there were 7 major (e.g., severe flap infection requiring explantation, cholesteatoma, persistent eardrum perforation) and 14 minor complications (e.g., mild flap infection, flap swelling, hematoma). A number of complications were encountered even 14 years after the original operation, and some of them needed repeated interventions, highlighting the importance of long-term follow-up. However, most of the complications occurred very close to the surgical procedure (<1 yr). Conclusion: An overall rate of 2.3% for major surgical complications and an overall rate of 16% for minor surgical complications suggest that cochlear implantation is a relatively safe surgical operation in experienced centers. Most surgical complications are minor and can be managed with conservative treatment or minor surgical intervention. However, meticulous attention to surgical detail, especially handling soft tissues and leaving the posterior canal wall intact, and long-term follow-up are of paramount importance in minimizing the incidence of surgical complications.

Approach to communication, speech perception and intelligibility after paediatric cochlear implantation.

Abstract The aim of this study was to explore the relationship between approach to communication, speech perception and speech intelligibility after cochlear implantation of young children with profound early deafness. A prospective speech perception and speech intelligibility assessment was undertaken on a consecutive group of implanted children. There were 46 children at the three-year, 26 at the four-year and 20 at the five-year intervals. All had been born deaf or deafened before the age of three and received cochlear implants before the age of seven. Their speech perception ability and the intelligibility of their speech were measured before cochlear implantation and annually thereafter. The childrens communication had been classified by their teachers of the deaf at each interval into one of two categories: those using an oral approach and those using a signing approach. Results revealed that at all intervals, those children classified as using oral communication significantly exceeded those using signed communication on measures of speech perception and intelligibility (p<0.05). When those children who had changed from signed to oral communication were compared at the three-year interval with those who used oral communication throughout, there was no significant difference in their results. However, it remains to be explored whether children use oral communication after cochlear implantation because they are doing well, or whether they do well because they are using oral communication.

Bilateral Cochlear Implantation: An Evidence-Based Medicine Evaluation

Objectives/Hypothesis: The aim of this study was to evaluate the extent and quality of evidence reported on the outcomes of bilateral cochlear implantation and thereby to inform opinion about future patient management.

Is there a correlation between vascular loops and unilateral auditory symptoms

Objectives: To assess whether contact of a vascular loop formed by the anterior inferior cerebellar artery (AICA) with the eighth cranial nerve correlated with unilateral auditory symptoms so as to produce a “vascular compression syndrome.” Study Design: Prospective evaluation of patients with unilateral auditory symptoms using magnetic resonance imaging (MRI) scans to identify contact of a vascular loop with the eighth cranial nerve. Methods: One hundred twelve patients with idiopathic unilateral auditory symptoms (42 women and 70 men, mean age of 51 years) were evaluated with MRI. Location of the vascular loop and contact with the eighth cranial nerve were assessed in each case. The asymptomatic contralateral ears of the patients were used as controls. A power analysis had determined the size of the sample to be studied. Results: The arterial loop was found to be in contact with the eighth cranial nerve in 28 (25%) of the 112 symptomatic ears and in 24 (21.4%) of the asymptomatic (control) ears. The statistical analysis revealed that the difference was not statistically significant. Conclusion: The results suggest that radiologic demonstration of contact between a vascular loop formed by the AICA and the eighth cranial nerve on MRI scans should be considered a normal anatomic finding and should not, on its own, be used to support the diagnosis of a “vascular compression syndrome.” Laryngoscope, 108:1739–1742, 1998

Spatial hearing disability after acoustic neuroma removal.

Objectives/Hypothesis: Previous studies on hearing loss (HL) after acoustic neuroma removal concentrate mainly on pure‐tone hearing results rather than hearing disability. Our objectives were to use the Speech, Spatial and Qualities of Hearing scale (SSQ), a comprehensively validated questionnaire, to characterize and quantify the auditory disabilities that patients experience with a profound unilateral HL after acoustic neuroma removal.

Educational placement of deaf children following cochlear implantation.

This study examined the educational placements, before cochlear implantation, of 121 deaf children, and the educational placements, two years after implantation, of the 48 children who had reached that stage, looking at the influence of age at implantation and duration of deafness on the placement of these children. In addition, it compared the educational placements of those given implants prior to schooling, and those given implants when already in an educational setting. Categories used were pre-school, school for the deaf, unit or resource base within a mainstream school and full-time mainstream provision. Age at implantation and duration of deafness were found to be significant predictors of placement two years after implantation. The duration of deafness of children in schools for the deaf or units was twice that of children in mainstream education. Fifty-three per cent of children who were in pre-school at the time of implantation were in mainstream schools two years after implantation, whereas only 6% of those who were already in educational placements at the time of implantation were in mainstream education. This difference was statistically significant. The results indicate that children who are given implants early, before an educational decision has been made, are more likely to go to mainstream schools than those given implants when already in an educational setting.

Hearing without ears: do cochlear implants work in children?

Profound deafness in early childhood has major consequences for the child, its family, and society. Critical periods exist for speech and language development during which the developing nervous system is particularly responsive to auditory stimulation. Inadequate sensory input during these periods leads to lifelong linguistic and communicative deficits.1 Fortunately, if identified early enough, most hearing losses can be satisfactorily managed by hearing aids and rehabilitation. Until the advent of cochlear implantation, however, the outlook for children who were too deaf to hear speech through a hearing aid was less promising and they often failed to develop intelligible spoken language. Conrad found that the median reading age of profoundly deaf 16year olds was that of normal hearing 9year olds and that no fewer than half these children could not read.2 As a consequence, their educational and employment opportunities were restricted. In the United Kingdom about 220children are born each year with hearing losses in excess of 95dB and a further 80lose their hearing, mainly through bacterial meningitis.3 In profoundly deaf patients auditory nerve …

Intra-operative recordings of electrically evoked auditory nerve action potentials in young children by use of neural response telemetry with the Nucleus CI24M cochlear implant

Abstract The electrically evoked action potential (EAP) was recorded intra-operatively by use of neural response telemetry (NRT) on the Nucleus CI24M cochlear implant. The aim of the present study was to investigate the EAP in young children immediately following implant surgery and whilst the children were still anaesthetized. The effect of data collection parameters on the reliability of the EAP was assessed and the relationships of the EAP findings to the intra-operative electrical auditory brainstem response (EABR) and early behavioural threshold levels (T-levels) were also investigated. The study data comprised intra-operative recordings in 60 children. Age at implantation was less than five years in 42 (70%) of the children. Aetiology of deafness was congenital in the majority of children (55, 92%), meningitic in four children and of unknown origin in one child. Optimum test parameters for the intra-operative EAP were an amplifier gain of 40 dB and a delay of 50 us in order to minimize the effects of amplifier saturation due to stimulus artefact and to maximize the identification of the Nl component. An intra-operative protocol was established which involved recording four stimulus levels on each of the 22 electrodes of the electrode array, the range of stimulus levels being tailored towards the expected EAP thresholds and T-levels so as to identify response threshold. There was significant correlation between the intraoperative EAP thresholds and the early T-levels (Pearson’s r = 0.93;p<0.01) when a correction factor was introduced based on a reliable behavioural measure of the threshold of electrical stimulation on electrode 10. The intra-operative EAP threshold, when combined with a limited amount of behavioural data, may therefore be used to predict the T-level with a useful degree of accuracy. This result is also supported by the significant correlation observed between the intra-operative thresholds of the EAP and EABR.

Cochlear implants in children: principles, practice and predictions.

An audit was undertaken of the first 36 children who had received cochlear implants in Nottingham. These children had previously derived no benefit from prolonged trials of powerful hearing aids. Following implantation, all children could hear warble tones at all audiometric frequencies from 500 to 4000 Hz at sound pressure levels between 30 and 50 dB. The majority of children implanted below the age of 5 years developed intelligible spoken language after 3 years. The outcomes for children born deaf and those who acquired deafness under the age of 3 years were substantially similar. The best results were obtained in those children who were implanted before the age of 5 years or in whom the deafness was of short duration. The needs of implanted children continue over many years. A small number of dedicated, well-funded multidisciplinary teams are needed to meet the growing demand nationally.