Speech recognition ability as a function of duration of deafness in multichannel cochlear implant patients.

Surgical implantation of a multichannel cochlear prosthesis has become a widespread treatment for profound hearing loss. The relationship between duration of hearing loss and speech recognition ability was examined in 20 postlinguistically deafened adults using the Nucleus 22-Channel Cochlear Prosthesis. Data analysis indicated statistically significant negative correlations between duration of profound hearing loss and postoperative performance on the Central Institute for the Deaf Everyday Sentence Test and the Northwestern University Monosyllabic Word Test (NU-6). Age at implantation and age at onset of profound hearing loss were not found to be significantly correlated with performance on the two measures. These findings are discussed in terms of patient counseling and prediction of potential benefit to the patient.

Speech perception abilities of adult and pediatric Nucleus implant recipients using the Spectral Peak (SPEAK) coding strategy.

A series of 73 postlinguistically deafened adults and 34 prelinguistically deafened children were evaluated with the Spectral Peak (SPEAK) coding strategy of the Nucleus 22-channel cochlear implant. The adults who received consecutive implants demonstrated rapid acquisition of open-set speech recognition skills in the initial postoperative period. Group mean sentence recognition improved to 53.5% (n = 52) after 2 weeks, 62.1% (n = 55) after 1 month, 69.8% (n = 57) after 3 months, and 74.4% (n = 42) after 6 months of use. At the 6-month evaluation interval, 43% of subjects scored greater than 90% on sound-alone sentence recognition in quiet and only one patient (2.4%) scored less than 10%. Mean monosyllabic word recognition was 35.6% after 6 months of use. The 34 prelinguistically deafened children were converted from the Multipeak strategy to Spectral Peak strategy at four large pediatric implant centers. After 6 months of using the new coding strategy, the children demonstrated significant improvements in their speech perception abilities.

Vowel production in a prelinguistic child following cochlear implantation.

Formant frequencies were determined from vocalic utterances of a prelinguistically deafened child implanted with a Nucleus 22-channel device at age 5 years. Speech samples were obtained from recordings of speech made 5 and 2 months prior to implantation and at 6, 12, 18, 24, and 36 months post implantation. Prior to implantation, first formant values showed a greater range than those of normal hearing children of comparable age, and second formant values showed a greatly reduced range and clustered around a mean of 1800 Hz. By 36 months post implantation, first formant values approximated age-matched norms. By 6 months post implantation, higher second formant values were apparent. A progressive shift in second formant values was noted through 36 months post implantation when the vocalic space most closely corresponded to age-matched normative data.

Facial nerve stimulation after successful multichannel cochlear implantation.

Postoperative rehabilitation after cochlear implantation may be difficult and frustrating for both patient and audiologist. The occurrence of facial nerve stimulation with associated twitching and discomfort can interfere with the rehabilitative process and be a cause of great concern to the patient. Such stimulation can occur at the time of initial "tune-up" or can be delayed by months or years. The incidence of postoperative facial nerve stimulation 109 consecutive patients operated by the same surgeon over a period of 7 years is reviewed. Possible causes for immediate and delayed stimulation are discussed, and strategies at surgery are outlined. Rehabilitative techniques for dealing with facial nerve stimulation are reviewed.

Speech perception after multichannel cochlear implantation in the pediatric patient.

Clinical trials to evaluate multichannel cochlear implantation in children ages 2 to 17 years began in late 1986, with pre-market approval granted in 1990. To date, 870 children in the United States have received the Nucleus 22-channel device. Performance on measures of speech perception in 30 children who have used the Nucleus cochlear implant for a minimum of 6 months is presented and discussed in terms of the predictive value of patient biographic variables. Age at implantation and age to deafness onset were positively correlated with test performance for pre- and perilinguistically deafened subjects.