Evaluation of Nucleus 6 Sound Coding Algorithms

The purpose of the study was to evaluate the features of the Nucleus 6 Sound Processor (CP900 series) on existing Nucleus recipients who currently use the previous generation sound processor, the Cochlear Nucleus CP810 (also commonly known as the Nucleus 5), with a Cochlear Nucleus CI24RE, CI512 or CI422 cochlear implant. The features evaluated included an enhanced Automatic Gain Control (eAGC), the option to provide acoustic amplification in combination with traditional electric stimulation through an acoustic component, and three input processing algorithms: Signal to Noise Ratio - Noise Canceller (SNR-NC), Wind Noise Reduction (WNR) and Automatic Scene Analyzer (SCAN).

As is customary for a single-subject research design, study results will be analyzed for each subject individually. For evaluations where testing took place under two conditions (i.e. Endpoint 2, 3, 4, and 5) a non-inferiority hypothesis test based on the paired comparisons of the % of words correct will be performed. For each subject, the paired difference (P1 minus P2) will be calculated and the mean difference will be tested statistically against a non-inferiority null hypothesis of 10%. Successful rejection of the null hypothesis allows for a conclusion that the performance under the test condition 2 (based on the Nucleus 6 sound processor) will be non-inferior to the test condition 1 (based on the Nucleus 5 sound processor).

Ho: P1 - P2 ≥ 10% Ha: P1 - P2 < 10%

We hypothesize acceptance of the null hypothesis for the Nucleus 6 features.

Testing will be based on a paired t-test with a one-sided 0.05 alpha level. The value of 10% was selected as the non-inferiority margin as one that can be tested with reasonable power and was clinically meaningful.