[The Clarion cochlear implant--technical principles, initial clinical experiences and results].

BACKGROUND

Certain design characteristics of the Clarion device (Advanced Bionics Corp.) make it significantly different from other cochlear implant systems. It has a preformed electrode array to be placed closer to the modiolus, thus providing a more efficient coupling of the electrical signal to the auditory nerve; a telemetric function which permits the evaluation of the implant electronics; and two different speech processing strategies. The strategies are continuous interleaved sampling (CIS) and compressed analog (CA); both can be programmed into the same speech processor and alternatively selected by the patients, as they desire. The surgical procedure is only slightly different from the procedure familiar from the Nucleus system with the exception of a significantly larger cochleostomy.

PATIENTS

The results of a series of speech tests designed to evaluate benefit in terms of speech understanding were administered to the first ten Clarion patients and compared to the results of a similar group of patients using the Nucleus system and the M Peak method. From a data-base of more than 300 Nucleus users, it was possible to select ten subjects who had near-equivalent data for onset of deafness, duration of deafness, and age at implantation (so-called matched pairs). In the majority of cases, etiology and course of deafness (progressive or sudden) could also be matched.

RESULTS

It was found that the Clarion patients had higher test scores than the Nucleus patients after two weeks, three months, and six months after implantation. This positive experience with the Clarion device encouraged us to continue implanting this system in patients. As of September 1995, 106 patients (including 35 children between the ages of two and fourteen) are currently enrolled in the study.

CONCLUSIONS

A final assessment of results with the Clarion implant is not possible because of the short follow-up. In any case, it appears that the patients with this implant system achieve faster open-set speech understanding and that it is accomplished with less effort in programming and shorter rehabilitation time.