Objective: Recommendation for cochlear implant (CI) treatment for individuals with severe to profound single-sided deafness (SSD) and asymmetrical hearing loss (AHL) is on the rise. This raises the need for greater consistency in the definition of CI candidacy for these cases and in the assessment methods of patient-related benefits to permit effective comparison and interpretation of the outcomes with both conventional and implantable options across studies. Method: During a dedicated seminar on implant treatment in AHL patients, the panellists of the closing round table reviewed the clinical experience presented with the aim to define clear audiometric characteristics for both AHL and SSD cases, as well as a common data set enabling consistent evaluation of hearing benefits in this population. Conclusions: The panellists agreed on a clear differentiation between AHL and SSD CI candidates, defining average pure-tone thresholds up to 4 kHz for better and poorer ears. Agreement was reached on a minimum set of assessment procedures, and included the necessity of trials with conventional CROS/BICROS hearing aids and bone conduction devices before considering CI treatment. Objective assessment of sound localisation abilities was identified as the most relevant criterion to quantify performance before and after treatment. In parallel, subjective assessment of overall hearing ability was recommended via the Speech, Spatial and Qualities of hearing questionnaire. Longitudinal follow-up of these parameters and the hours of daily use were considered essential to reflect the potential treatment benefits for this population. The consistency in the data collection and its report will further support health authorities in their decision on acceptable gains from available hearing loss treatment options.

We evaluated the relationship between binaural hearing deficits and quality of life. The study included 49 adults with asymmetric hearing loss (AHL), and 11 adult normal-hearing listeners (NHL) served as controls. Speech reception thresholds (SRT) were assessed with the French Matrix Test. Quality of life was evaluated with the Speech, Spatial and Qualities of Hearing Scale (SSQ) and the Glasgow Health Status Inventory. Speech recognition in noise was significantly poorer for AHL subjects [-0.12 dB signal-to-noise ratio (SNR) in dichotic (with speech presented to the poorer ear and noise to the better ear), -1.72 dB in diotic and -6.84 dB in reverse-dichotic conditions] compared to NHL (-4.98 dB in diotic and -9.58 dB in dichotic conditions). Scores for quality-of-life questionnaires were significantly below norms. Significant correlations were found between the SRT for the dichotic condition and the SSQ total score (r = -0.38, p = 0.01), and pure-tone average thresholds for both groups.

Introduction: Cochlear implantation is a recent approach proposed to treat single-sided deafness (SSD) and asymmetric hearing loss (AHL). Several cohort studies showed its effectiveness on tinnitus and variable results on binaural hearing. The main objective of this study is to assess the outcomes of cochlear implantation and other treatment options in SSD/AHL on quality of life. Methods: This prospective multicenter study was conducted in 7 tertiary university hospitals and included an observational cohort study of SSD/AHL adult patients treated using contralateral routing of the signal (CROS) hearing aids or bone-anchored hearing systems (BAHSs) or who declined all treatments, and a randomized controlled trial in subjects treated by cochlear implantation, after failure of CROS and BAHS trials. In total, 155 subjects with SSD or AHL, with or without associated tinnitus, were enrolled. After 2 consecutive trials with CROS hearing aids and BAHSs on headband, all subjects chose any of the 4 treatment options (abstention, CROS, BAHS, or cochlear implant [CI]). The subjects who opted for a CI were randomized between 2 arms (CI vs. initial observation). Six months after the treatment choice, quality of life was assessed using both generic (EuroQoL-5D, EQ-5D) and auditory-specific quality-of-life indices (Nijmegen Cochlear implant Questionnaire [NCIQ] and Visual Analogue Scale [VAS] for tinnitus severity). Performances for speech-in-noise recognition and localization were measured as secondary outcomes. Results: CROS was chosen by 75 subjects, while 51 opted for cochlear implantation, 18 for BAHSs, and 11 for abstention. Six months after treatment, both EQ-5D VAS and auditory-specific quality-of-life indices were significantly better in the “CI” arm versus “observation” arm. The mean effect of the CI was particularly significant in subjects with associated severe tinnitus (mean improvement of 20.7 points ± 19.7 on EQ-5D VAS, 20.4 ± 12.4 on NCIQ, and 51.4 ± 35.4 on tinnitus). No significant effect of the CI was found on binaural hearing results. Before/after comparisons showed that the CROS and BAHS also improved significantly NCIQ scores (for CROS: +7.7, 95% confidence interval [95% CI] = [4.5; 10.8]; for the BAHS: +14.3, 95% CI = [7.9; 20.7]). Conclusion: Cochlear implantation leads to significant improvements in quality of life in SSD and AHL patients, particularly in subjects with associated severe tinnitus, who are thereby the best candidates to an extension of CI indications.

Objectives: The detection of fundamental frequency (F0) variations plays a prominent role in the perception of intonation. Cochlear implant (CI) users with residual hearing might have access to these F0 cues. The objective was to study if and how residual hearing facilitates speech prosody perception in CI users. Design: The authors compared F0 difference limen (F0DL) and question/statement discrimination performance for 15 normal-hearing subjects (NHS) and two distinct groups of CI subjects, according to the presence or absence of acoustic residual hearing: one “combined group” (n = 11) with residual hearing and one CI-only group (n = 10) without any residual hearing. To assess the relative contribution of the different acoustic cues for intonation perception, the sensitivity index d’ was calculated for three distinct auditory conditions: one condition with original recordings, one condition with a constant F0, and one with equalized duration and amplitude. Results: In the original condition, combined subjects showed better question/statement discrimination than CI-only subjects, d’ 2.44 (SE 0.3) and 0.91 (SE 0.25), respectively. Mean d’ score of NHS was 3.3 (SE 0.06). When F0 variations were removed, the scores decreased significantly for combined subjects (d’ = 0.66, SE 0.51) and NHS (d’ = 0.4, SE 0.09). Duration and amplitude equalization affected the scores of CI-only subjects (mean d’ = 0.34, SE 0.28) but did not influence the scores of combined subjects (d’ = 2.7, SE 0.02) or NHS (d’ = 3.3, SE 0.33). Mean F0DL was poorer in CI-only subjects (34%, SE 15) compared with combined subjects (8.8%, SE 1.4) and NHS (2.4%, SE 0.05). In CI subjects with residual hearing, intonation d’ score was correlated with mean residual hearing level (r = −0.86, n = 11, p < 0.001) and mean F0DL (r = 0.84, n = 11, p < 0.001). Conclusion: Where CI subjects with residual hearing had thresholds better than 60 dB HL in the low frequencies, they displayed near-normal question/statement discrimination abilities. Normal listeners mainly relied on F0 variations which were the most effective prosodic cue. In comparison, CI subjects without any residual hearing had poorer F0 discrimination and showed a strong deficit in speech prosody perception. However, this CI-only group appeared to be able to make some use of amplitude and duration cues for statement/question discrimination.