Benefits from upgrade to the CP810 sound processor for Nucleus 24 cochlear implant recipients

The objective of this study was to measure performance benefits obtained by upgrading recipients of the Cochlear Nucleus CI24 cochlear implant to the new CP810 sound processor. Speech recognition in quiet and in spatially separated noise was measured in established users of the Cochlear ESPrit 3G (n = 22) and Freedom (n = 13) sound processors, using the "Everyday" listening program. Subjects were then upgraded to the CP810 processor and were re-assessed after a 3-month period, using both the "Everyday" program and the new "Noise" program, which incorporates several pre-processing features including a new directional microphone algorithm ("Zoom"). Subjective perceptions were also recorded using the abbreviated profile of hearing aid benefit (APHAB) questionnaire. Mean scores for monosyllables in quiet, presented at 50 and 60 dB SPL, increased by 11% (p < 0.0001) and 8% (p < 0.001), respectively, after upgrade, for all subjects combined. Significant increases were also recorded for both processor groups. In noise, the mean scores were 60.0 and 67.4% for the original and CP810 Everyday programs, respectively (difference not significant). With the CP810 Noise programs the mean score increased to 82.5% (p < 0.01), with significant increases in both processor groups. There was evidence of slightly greater upgrade benefit in users of the ESPrit 3G processor and in relatively poor performers. The APHAB questionnaire also indicated significant reduction in perceived difficulty in the background noise and reverberation sub-scales after upgrade. The findings of the study appear to support the expectation of increased benefit from the new CP810 sound processor.