Development and application of a health-related quality-of-life instrument for adults with cochlear implants: the Nijmegen cochlear implant questionnaire.

OBJECTIVE: The goal was to develop a quantifiable, self-assessment health-related quality of life (QoL) instrument for use in cochlear implant (CI) users. DESIGN: Three principal domains were distinguished: physical, psychological, and social. Forty-five postlingually deaf adult multichannel CI users and 46 deaf candidates on the waiting list for CIs (control group) participated in the study. RESULTS: Retrospective scores for the CI group corresponded very well with the scores for the control group. Current QoL scores were substantially higher for all 6 subdomains. Internal consistency and testretest reliability coefficients proved to be satisfactory, and the ability to detect clinical changes with the Nijmegen Cochlear Implantation Questionnaire (NCIQ) proved to be good. CONCLUSIONS: The psychometric characteristics of the NCIQ proved to be reliable and probably valid and sensitive to clinical changes. The data obtained with the NCIQ reflected that the instrument was able to detect that a CI had significant effects on several health-related QoL aspects, including the social and psychological domains.

The effect of cochlear implant use in postlingually deaf adults.

OBJECTIVE: To assess the effect of the use of cochlear implants (CI) on the health status of postlingually deaf adults. METHODS: Participants comprised 45 postlingually deaf adult multichannel CI users and 46 deaf candidates on the waiting list for a CI. The latter group acted as control subjects to corroborate the validity of retrospective completion of the questionnaires by the CI recipients. Three HRQOL instruments were used: a) a specially developed CI questionnaire (NCIQ); b) a generic HRQOL questionnaire (SF-36); and c) a health-state classification system (HUI-2) suited to estimate single preference scores. RESULTS: Retrospectively estimated pre-implant scores in the CI user group corresponded very well with the scores in the control group. Postimplant scores in the CI users were substantially higher in all six domains (p < .001) of the NCIQ than the scores in the control group. Effects due to a CI were also observed with the SF-36 in five of the seven domains (p < .01). Statistically significant differences between the two groups (p = .001) were observed in two of the six domains of the HUI-2. CONCLUSIONS: All three questionnaires detected improvements in HRQOL due to CI use. To make a detailed assessment of the effect of a CI on functional outcomes and well-being, a special purpose HRQOL instrument is far more adequate than a general HRQOL instrument. This study also showed that a CI affects several other health domains besides auditory performance. The effect of CI use on general functioning and well-being proved to be considerable.

Can event-related potentials be evoked by extra-cochlear stimulation and used for selection purposes in cochlear implantation?

To investigate whether electrically evoked event-related responses (P300) could be elicited by extra-cochlear stimulation, measurements were performed on a group of adults fitted with the single-channel extra-cochlear implant. To optimize measurement conditions, and because of the low number of subjects still using an extra-cochlear device in our cochlear implant programme, measurements were also performed on a group of experienced users fitted with the intra-cochlear Nucleus multichannel device. For reference purposes, subjects with normal hearing (control group) were also included in the study. Reproducible late latency responses (N1 and P2 peaks) were found in the five extra-cochlear implant users, while P300s were present in four out of these five subjects. The latencies were longer than those of the control group, but were similar to those obtained in the intra-cochlear implant group. Significant correlations were found for most N1, P2 and P300 measurements evoked by the tonal stimuli and by speech stimuli. The P300 amplitudes, evoked by either tonal or speech stimuli, appeared to be related to speech perception ability. This led to the conclusion that N1, P2 and P300 measurements may have potential as a clinical tool for preoperative prediction and postoperative evaluation of sound processing on a cortical level.

Performance of prelingually and postlingually deaf patients using single-channel or multichannel cochlear implants.

The auditory and aided lipreading performance of 8 prelingually and 11 postlingually deaf patients who had received a single-channel or multichannel cochlear implant was evaluated during 2 years of follow-up. Although all the patients improved on both closed-set pattern recognition and speech discrimination tests and on a Continuous Discourse Tracking task, the most significant improvement was observed in the postlingually deaf patients who were using a multichannel implant. These patients were the only ones to achieve open-set speech recognition in the auditory-only condition. Only small differences were found between prelingually deaf patients who were using a single-channel system and those who were using a multichannel system. The users' evaluations, obtained by means of a questionnaire, were generally positive in all patients. Based on the study results, the authors concluded that it is feasible to use cochlear implants in highly motivated prelingually deaf patients who have learned to use oral-aural communication.

The risk of vestibular function loss after intracochlear implantation.

Sixty patients were selected for cochlear implantation and 50 of them received an intracochlear implant (Nucleus). Vestibular function was evaluated before and after surgery using a caloric test and a velocity step test. Sixteen patients had normal or residual vestibular function before surgery, 11 bilateral and 5 unilateral; in 3 of the latter patients, the ear with vestibular areflexia was elected for implantation, which reduced the number of patients at risk for vestibular dysfunction to 13. Vestibular function was preserved in all of these patients except for 4; the risk of vestibular function loss can therefore be rated at about 31%.

Performance of prelingually or postlingually deafened adults who were using a single or multichannel cochlear implant.

Long-term (two-year post-implantation) speech recognition was evaluated of prelingually and postlingually deafened adult cochlear implant users who had received either a single or a multichannel device. The patient group comprised 8 pairs of patients matched according to the onset and duration of deafness; in each pair one patient had an extra-cochlear single-channel implant and one had an intra-cochlear multichannel implant. A CDT (Continuous Discourse Tracking) test and a closed-set speech recognition test were used for speech recognition. The results of the postlingually deafened pairs of patients showed that the multichannel implant was superior to the single-channel implant, which is in agreement with other studies. In the pairs of prelingually deafened adult patients, the multichannel system was not found to be superior. This warrants further study and further application of single-channel implants in prelingually deafened patients.

Development of the spinal projections of the nucleus paraventricularis hypothalami of the rat: an intra-uterine WGA-HRP study.

The development of the spinal projections of the nucleus paraventricularis hypothalami (PVH) was studied by injecting wheatgerm-agglutinated horseradish peroxidase into the upper thoracic spinal cord of fetal rats at developmental ages ranging from embryonic day 16 (E16) to E21, and into the thoracic spinal cord of rat pups and adult rats. At E18 the first retrogradely labeled cells are seen in the PVH. These cells are located dorsally in the PVH, adjacent to the ventricular matrix. At E20 a more ventrally located group of retrogradely labeled cells appears. This ventral group joins caudally with the dorsal group of labeled cells. The dorsal group of labeled cells is closely packed, while the ventral group of labeled cells is intermingled with unlabeled cells. After E20 this spatial configuration remains essentially constant. Therefore descending projections from all spinal projecting cell groups in the PVH have reached lower cervical spinal cord levels at E20.