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.

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.

Sixty patients were selected for cochlear implantation and 50 of them received an intracochlear implatu (Nucleus). Vestibular function was evaluated before and after surgery using a calorie 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 arellexia 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%.

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.

Individual results are presented of 4 patients with Usher's syndrome type 1 who received a cochlear implant. Both single-channel and multichannel implants were used. Because of implant failure, one of the single-channel systems was replaced by a Nucleus multichannel system. Results are compared to the results of 5 other prelingually deaf cochlear implant users. The performance of the patients with Usher's syndrome on suprasegmental and segmental speech perception tests and on a connected discourse tracking task did not differ significantly from the performance ofthe other prelingually deaf patients. A significant improvement over time was found at the suprasegmentallevel for the combined group of Usher's and other patients. No obvious differences were found between the scores from the patients with a single-channel and the patients with a multichannel device. The rehabilitation of the Usher's patients required very little extra effort in comparison with that of the other prelingually deaf patients; all patients reported considerable advantages in hearing abilities and social life.