An intraoperative test protocol for objective assessment of the nucleus 22-channel cochlear implant. Nottingham Paediatric Cochlear Implant Programme

Assessment of the functioning of peripheral auditory pathways after cochlear re-implantation in young children using intra-operative objective measures

The intra-operative electrical auditory brainstem response (EABR), electrical stapedius reflex threshold (ESRT) and the early post-operative behavioural threshold level (T-level) were recorded in five children undergoing cochlear re-implantation. The aim of the study was to assess objectively the effect of re-implantation on intra-operative objective measures and to investigate neuronal function. The children were aged between 2.06 years and 4.5 years at first implantation. Following failure of the first device, re-implantation was carried out 1.42-5.52 years later. Characteristics of the EABR and ESRT across the electrode array were typical of the expected pattern of responses on both occasions. In particular, the slopes of the amplitude input/output (I/O) functions for wave eV of the intraoperative EABR were similar for both the first and second implants even though absolute thresholds were generally elevated after re-implantation. This elevation in intra-operative threshold was more pronounced than the change in early post-operative behavioural threshold level for electrical stimulation (T-level). Our findings confirm a high level of neuronal survival after re-implantation. Threshold of the intra-operative EABR at the time of re-implantation greatly underestimates the sensitivity of the subsequent early post-operative T-levels.

Current practice of paediatric chochlear implantation in nottingham

The number of integrated paediatric cochlear implantation programme are very few in the world. In U.K. this pioneering integrated paediatric chochlear implantation programme has been started in the year 1989 under the supervision of group of dedicated paediatric personnel comprising of ENT surgeons, neuro-radiologist, audiologist, speech therapist, orthophonists, teachers of the deaf and others associated with the deaf children. Only the surgical procedure of cochlear implantation is not the answer of a profound sensorineural deaf child who can not be helped by conventional hearing aids. Proper selection of the cases, pre-operative counselling, pre-operative audiological and non-audiological investigations are of immense value. Similarly the programme following surgery as a team approach is equally important for proper rehabilitation of profound sensorineural deaf child who can not be helped by conventional hearing aids.

Cochlear implantation: a review of the literature and the Nijmegen results

The field of cochlear implantation is developing rapidly. In subjects with bilateral profound deafness who gain no benefit from conventional hearing aids the aim of cochlear implantation is to provide a means for them to receive auditory sensations. Throughout the world, most cochlear implant centres are still continuing their research efforts to improve the results with this technique. Although it is still difficult to predict how an individual will perform with a cochlear implant, the success of cochlear implantation can no longer be denied. In this paper, we review some recent papers and reports, and the results of the various Nijmegen cochlear implant studies. Data about subject selection, examinations, surgery and the outcome are discussed. Our results were in good agreement with those of other authors. It can be concluded once again that cochlear implantation is an effective treatment for postlingually deaf adults and children, and for prelingually (congenital or acquired) deaf children with profound bilateral sensorineural deafness.

Cochlear implantation in deaf children

A cochlear implant (CI) is a hearing device introduced in the 1980s for profoundly deaf subjects who gained little or no benefit from powerful hearing aids. This device comprises an electrode array inserted in the cochlea, connected to an internal receiver, and an externally worn speech processor. The CI transforms acoustic signals into electrical currents which directly stimulate the auditory nerve. Since the early 1990s, cochlear implantation in children has been developing rapidly. Although it is still difficult to predict how a child will perform with a cochlear implant, the success of cochlear implantation can no longer be denied. In this paper, some recent papers and reports, and the results of the various Nijmegen cochlear implant studies, are reviewed. Issues about selection, examinations, surgery and the outcome are discussed. Overall, our results were comparable with those of other authors. It can be concluded that cochlear implantation is an effective treatment for postlingually deaf as well as prelingually (congenital or acquired) deaf children with profound bilateral sensorineural deafness.

Intraoperative electrophysiological and objective tests after cochlear re-implantation in a young child

The electrically evoked auditory brainstem response (EABR) and stapedius reflex threshold (ESRT) are routinely recorded during implant surgery with the Nucleus 22 channel cochlear implant in the Nottingham Paediatric Cochlear Implant Programme and are extremely valuable in the management of young implanted children. These intraoperative tests were carried out in a young child on the occasion of the first implantation and then after re-implantation 17 months later following malfunction of the first device. The surgical experiences of the first implantation and the re-implantation were both straightforward. Recordings of the intraoperative EABR and ESRT were typical of the expected pattern of responses on both occasions and there was only a small reduction in threshold sensitivity after re-implantation. These investigations provide valuable objective information to support and assist with the management of re-implantation in a young child.