Article
Comparison of the Results with Different Cochlear Implant Electrodes (Straight, Contour, Contour with Softip)
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Published: | September 22, 2005 |
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Introduction: During the last twenty years, cochlear implants underwent a terrific development. A major focus was put on the development of modiolus hugging electrode arrays and an atraumatic insertion procedure. These improvements should lead to a reduction in stimulation levels and also to an increased speech understanding for the patients.
Methods: Data from all patients implanted with a Nucleus cochlear implant and one of the following electrode arrays were extracted from the database at MHH: A) Straight electrode (far from the modiolus, N=69), B) Contour electrode (modiolus-hugging, N=153) or C) Contour electrode with Softip (atraumatic insertion, N=37). Retrospectively, the threshold (T) and comfort (C) -level from first fitting until one year post surgery and, additionally, speech test results for the different groups were investigated.
Results: The transition from Straight to Contour electrode arrays reduced the mean T-levels by about 20 current levels (CL). Introduction of Contour electrodes with Softip resulted in a further reduction of about 5 CL. C-levels of groups B, and C did not show any difference but are reduced by 5 to 10 CL if compared to Straight electrode results. Therefore, the dynamic range is largest for the Contour electrode with Softip. The improved dynamic range also results in better speech test scores with this electrode array.
Conclusion: Each new electrode array increased the dynamic range and therefore also the range that can be used for speech coding. This enables a better speech processor fitting for the individual patients, which might be responsible for better speech test results.