Binaural cochlear implants.

With the success of monaural cochlear implantation, patients frequently ask about having a second implant. We have performed binaural cochlear implants in 12 adult patients. Desire not to disrupt a functioning implant was the primary consideration in implanting the contralateral ear. Seven patients received a second 3M/House single-channel implant to upgrade to a magnetic external receiver. Four patients with a 3M/House device in one ear elected to place a Nucleus multichannel implant in the opposite ear. One patient with a poorly functioning Nucleus device elected to have a second Nucleus device. Four patients with a Nucleus and a 3M/House implant, one with binaural 3M/House implants, and one with binaural Nucleus implants were tested for auditory discrimination in order to quantify monaural versus binaural differences. The functional benefit of the second implant was mixed, but all patients showed some degree of objective improvement on one or more tests. Five of the six are regular users of both devices; the patient with binaural Nucleus implants wears only one. Despite the differing processing schemes, patients with a Nucleus device in one ear and a 3M/House device in the other ear are able to combine the two signals to advantage. We feel that cochlear implantation in the contralateral ear is an acceptable option in selected patients desiring an upgraded implant without placing a functioning implant at risk.

Open-set speech recognition in children with a single-channel cochlear implant.

We evaluated the ability of profoundly deaf children using the 3M/House single-channel cochlear implant to understand speech without the aid of speechreading. Fifty-one implanted children over the age of 5 years, who had sufficient cognitive and language skills, were tested using word and sentence stimuli presented in an open-set, auditory-only mode. Fifty-two percent of the children demonstrated some open-set performance on word identification, while 41.5% did so on sentence comprehension. Children who scored open-set had a shorter duration of deafness than those who did not. A larger proportion of children using oral communication demonstrated open-set speech recognition than those using total communication. A multiple regression analysis indicated that communication method accounted for the largest proportion of variability in performance on both the word and sentence tasks. Children achieving open-set auditory recognition, however, included both those using oral communication and those using total communication, children deafened by meningitis and those born deaf, and children with varying durations of deafness.

The narrow internal auditory canal in children: a contraindication to cochlear implants.

We suggest a new explanation for the lack of auditory response to electric stimulation in children with cochlear implants: the very narrow internal auditory canal, 1 to 2 mm in diameter, and the probable absence of the cochlear nerve. This defect can be seen on high-resolution computed tomographic x-ray studies and may represent aplasia of the auditory-vestibular nerve. We report on eight children with this anomaly, three of whom have received implants and failed to respond with a sensation of sound. Identification of this problem on screening x-ray films is a contraindication to cochlear implantation for auditory stimulation.

Cochlear implants in children: benefits and concerns.

Cochlear implants have been used in investigational studies with profoundly deaf children aged 2 to 18 years. Results with the 3M/House implant indicate that this device is safe and effective. The implant provides auditory detection of much of the acoustic speech signal, significant improvement in auditory discrimination compared with preimplant with hearing aids, and improved speech production skills. A longitudinal control-group study of auditory discrimination and a cross-sectional study of speech using age-matched controls support the interpretation that these improvements are due to the cochlear implant. In addition, 26 of 50 children (52%) tested for open-set word recognition and 17 of 41 (41.5%) tested for open-set sentence comprehension demonstrated such abilities using the cochlear implant. Adverse effects have been minimal. Early results from three children with the Nucleus multichannel cochlear implant clearly indicate the efficacy of that device.

Experiences with the Nucleus multichannel cochlear implant in three young children.

Clinical trials for the Nucleus multichannel cochlear implant in children 2 through 9 years of age have been ongoing for approximately 1 year. We describe three children who have used the device for at least 8 months. Based on these three cases, we discuss some factors that might affect the outcome of the Nucleus implant in young children: age at implantation, age at onset of deafness, and duration of profound deafness before implantation. Surgical and rehabilitation issues, including educational settings, are reviewed.

Audiological results in children with a cochlear implant.

Audiological data collected through June 1984 were analyzed for 126 children with the cochlear implant. Preimplant hearing aid results were compared to cochlear implant results at 6-month follow-up test intervals. Auditory thresholds to warble tones and speech stimuli, and auditory discrimination test scores were significantly better with the cochlear implant at all test intervals than preoperatively with a hearing aid. Electrical measurements were also monitored. Mean thresholds remained consistent over time. Electrical comfort levels increased slightly over time, indicating a widening of the electrical dynamic range. Results have been extremely encouraging. Some trends are beginning to develop, but more long-term data are needed to define the potential benefit of the implant in children.