Multicenter clinical trial of the Nucleus Hybrid S8 cochlear implant: Final outcomes

Abstract

Objectives/hypothesis: The concept of expanding electrical speech processing to those with more residual acoustic hearing with a less-invasive shorter cochlear implant (CI) has been ongoing since 1999. A multicenter study of the Nucleus Hybrid S8 CI took place between 2002 and 2011. This report describes the final outcomes of this clinical trial.

Study design: Multicenter, longitudinal, single-subject design.

Methods: Eighty-seven subjects received a Nucleus Hybrid S8 CI in their poorer ear. Speech perception in quiet (Consonant-Nucleus-Consonant [CNC] words) and in noise (Bamford-Kowal-Bench Sentences-In-Noise [BKB-SIN]) were collected pre- and postoperatively at 3, 6, and 12 months. Subjective questionnaire data using the Abbreviated Profile for Hearing Aid Benefit (APHAB) were also collected.

Results: Some level of hearing preservation was accomplished in 98% subjects, with 90% maintaining a functional low-frequency pure-tone average (LFPTA) at initial activation. By 12 months, five subjects had total hearing loss, and 80% of subjects maintained functional hearing. CNC words demonstrated that 82.5% and 87.5% of subjects had significant improvements in the hybrid and combined conditions, respectively. The majority had improvements with BKB-SIN. Results also indicated that as long as subjects maintained at least a severe LFPTA, there was significant improvement in speech understanding. Furthermore, all subjects reported positive improvements in hearing in three of the four subscales of the APHAB.

Conclusions: The concept of hybrid speech processing has significant advantages for subjects with residual low-frequency hearing. In this study, the Nucleus Hybrid S8 provided improved word understanding in quiet and noise. Additionally, there appears to be stability of the residual hearing after initial activation of the device.

Level of evidence: 2c.

Keywords: Hybrid cochlear implant; acoustic plus electric; hearing preservation; short electrode; speech perception.

Conflict of interest statement

There are no other financial or conflicts of interest.

© 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Figures

Figure 1

Averaged unaided thresholds over the range 125 to 1000 Hz in the implanted ear shown preoperatively and post-operatively at initial activation, 3 months, 6 months, and 12 months.

Figure 2

Change in individual subject LFPTA at initial activation and longitudinally through 12 months post-implantation. Horizontal axis in each panel shows the pre-operative LFPTA versus post-operative LFPTA at initial activation (Panel A), three months (Panel B), six months (Panel C), and twelve months (Panel D) on the vertical axis.

Figure 3

Change in individual CNC word score. Horizontal axis in each panel shows the pre-operative CNC word score with hearing aid(s) versus postoperative CNC word score at 12 months in the Hybrid condition (Panel A), Combined condition (Panel B), CI only (Panel C), and Ipsilateral Acoustic (Panel D) on the vertical axis.

Figure 4

Change in individual BKB-SIN in noise score. Horizontal axis in each panel shows the pre-operative BKB-SIN score with hearing aid(s) versus postoperative BKB-SIN score at 12 months in the Hybrid condition (Panel A) and Combined condition (Panel B) on the vertical axis.

Figure 5

Averaged speech perception results pre-operatively and postoperatively over time at 3 months, 6 months and 12 months in the Combined, Hybrid and CI only conditions for CNC words (Panel A) and BKB-SIN (Panel B).

Figure 6

The influence of LFPTA on CNC word scores at the 12 months postoperative time point. The CNC word scores are shown by amount of functional hearing in the Combined (Panel A) and the Hybrid (Panel B) conditions where the subjects’ LFPTA was in the moderate, moderately-severe, or severe hearing range. The line represents the median and the “X” denotes the mean.

Figure 7

The influence of age at implantation and duration of hearing loss on CNC scores at the 12 months post-operative time point. The horizontal axis in Panel A shows the age at implantation in years and the horizontal axis in Panel B shows the duration of deafness in years. In each Panel, the vertical axis represents the CNC word score, the diamonds are representative of the Hybrid condition and the circles show the Combined condition. The solid line in each Panel represents the trendline for the Hybrid condition and the dashed lined is representative of the Combined condition.