The next generation of Nucleus(®) fitting: a multiplatform approach towards universal cochlear implant management

Abstract

Objective: This article provides a detailed description and evaluation of the next Nucleus(®) cochlear implant fitting suite. A new fitting methodology is presented that, at its simplest level, requires a single volume adjustment, and at its advanced level, provides access to 22-channel fitting. It is implemented on multiple platforms, including a mobile platform (Remote Assistant Fitting) and an accessible PC application (Nucleus Fitting Software). Additional tools for home care and surgical care are also described.

Design: Two trials were conducted, comparing the fitting methodology with the existing Custom Sound™ methodology, as fitted by the recipient and by an experienced cochlear implant audiologist.

Study sample: Thirty-seven subjects participated in the trials.

Results: No statistically significant differences were observed between the group mean scores, whether fitted by the recipient or by an experienced audiologist. The lower bounds of the 95% confidence intervals of the differences represented clinically insignificant differences. No statistically significant differences were found in the subjective program preferences of the subjects.

Conclusions: Equivalent speech perception outcomes were demonstrated when compared to current best practice. As such, the new technology has the potential to expand the capacity of audiological care without compromising efficacy.

Figure 1.

The fitting methodology and its control on program T- and C-levels (triangle and square markers, respectively). A. AutoNRT ECAP thresholds (circle markers) are measured (here at 22 electrodes intraoperatively). B. A program is instantly initialized, with an average dynamic range of 40CL, Master Volume set to 120 (inaudible or very soft), and Bass & Treble set to 0. C. Master Volume is gradually raised in the presence of live audio until comfortable. D. Bass & Treble are adjusted if desired. E. Three thresholds are measured if desired, bending the T-level profile. F. A Comfort check is performed if desired, adjusting selected bands of levels. Blocks A–D comprise the Remote Assistant Fitting methodology, and blocks A–F the Nucleus Fitting Software methodology. The deviation in levels at low frequencies is atypically large, chosen here to demonstrate the effect of profile scaling: the C-level profile is flatter than the T-level profile, and both profiles flatten when Master Volume is raised.

Figure 2.

Remote Assistant Fitting on the Nucleus CR110 Remote Assistant. Left: AutoNRT in progress on the second of five electrodes. Middle: Master Volume adjustment. Right: Treble adjustment.

Figure 3.

The Thresholds screen (left) and Comfort screen (right) of Nucleus Fitting Software. The two-screen design allows cochlear implant-specific detail to be avoided (for example, the Thresholds screen has an audiometer-like interface).

Figure 4.

Group mean speech perception test results for Remote Assistant Fitting, Nucleus Fitting Software, and Custom Sound fitting methods, all three fitted by an experienced cochlear implant audiologist. No significant differences were found in any of the test conditions. For the sentence tests (right), a lower speech reception threshold indicates better speech perception in noise. Error bars represent the standard errors of the means.

Figure 5.

Group mean speech perception test results for the Remote Assistant Fitting method, as fitted by a recipient, and the Custom Sound method, as fitted by an experienced cochlear implant audiologist. Group A testing occurred in the same session as the fitting procedure. No significant differences were found in any of the test conditions. Error bars represent the standard errors of the means. Note that sentence tests were also scored by the percentage of words correct.