Benefits of Cochlear Implantation for Single-Sided Deafness: Data From the House Clinic-University of Southern California-University of California, Los Angeles Clinical Trial

Abstract

Objectives: Cochlear implants (CIs) have been shown to benefit patients with single-sided deafness (SSD) in terms of tinnitus reduction, localization, speech understanding, and quality of life (QoL). While previous studies have shown cochlear implantation may benefit SSD patients, it is unclear which point of comparison is most relevant: baseline performance before implantation versus performance with normal-hearing (NH) ear after implantation. In this study, CI outcomes were assessed in SSD patients before and up to 6 mo postactivation. Benefits of cochlear implantation were assessed relative to binaural performance before implantation or relative to performance with the NH ear alone after implantation. Design: Here, we report data for 10 patients who completed a longitudinal, prospective, Food and Drug Administration–approved study of cochlear implantation for SSD patients. All subjects had severe to profound unilateral hearing loss in one ear and normal hearing in the other ear. All patients were implanted with the MED-EL CONCERTO Flex 28 device. Speech understanding in quiet and in noise, localization, and tinnitus severity (with the CI on or off) were measured before implantation (baseline) and at 1, 3, 6 mo postactivation of the CI processor. Performance was measured with both ears (binaural), the CI ear alone, and the NH ear alone (the CI ear was plugged and muffed). Tinnitus severity, dizziness severity, and QoL were measured using questionnaires administered before implantation and 6 mo postactivation. Results: Significant CI benefits were observed for tinnitus severity, localization, speech understanding, and QoL. The degree and time course of CI benefit depended on the outcome measure and the reference point. Relative to binaural baseline performance, significant and immediate (1 mo postactivation) CI benefits were observed for tinnitus severity and speech performance in noise, but localization did not significantly improve until 6 mo postactivation; questionnaire data showed significant improvement in QoL 6 mo postactivation. Relative to NH-only performance after implantation, significant and immediate benefits were observed for tinnitus severity and localization; binaural speech understanding in noise did not significantly improve during the 6-mo study period, due to variability in NH-only performance. There were no correlations between behavioral and questionnaire data, except between tinnitus visual analog scale scores at 6 mo postactivation and Tinnitus Functional Index scores at 6 mo postactivation. Conclusions: The present behavioral and subjective data suggest that SSD patients greatly benefit from cochlear implantation. However, to fully understand the degree and time course of CI benefit, the outcome measure and point of comparison should be considered. From a clinical perspective, binaural baseline performance is a relevant point of comparison. The lack of correlation between behavioral and questionnaire data suggest that represent independent measures of CI benefit for SSD patients.

Multifactorial positive influence of cochlear implantation on patients with single‐sided deafness

“…There are six subcategories: emotional and cognitive distress, intrusiveness, auditory perceptual difficulties, sleeping disturbances, somatic complaints, and total score. There are four tinnitus severity levels: low (score 1-30), moderate (31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46), severe (47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59), and very severe (60-84).…”

“…The tinnitus prevalence in previous SSD studies was in the range 46.4% to 90.9%. 2,13,28 There are several studies that reported a positive influence of CI on tinnitus distress in SSD patients 4,5,[26][27][28][29]41,42 ; however, in some studies there are heterogeneous groups with patients with SSD and asymmetric hearing loss, and there is no standardized test used for the evaluation of tinnitus distress.…”

Horizontal sound localisation and speech perception in Bonebridge-implanted single-sided deafness patients

“…2 Most studies have found that patients with single-sided deafness have poor sound localisation abilities and reduced speech perception abilities in noisy environments due to only receiving unilateral input. 1,[4][5][6] Traditionally, the contralateral routing of signal ('CROS') hearing aid, which was first introduced by Harford and Barry in 1965, was used to improve hearing in patients with single-sided deafness. 7 Many patients complain that the contralateral routing of signal device causes poor sound quality, discomfort and occlusion in the normal ear.…”

“…Studies have shown that cochlear implantation devices used in adults with single-sided deafness significantly decrease tinnitus and improve localisation, speech perception in noise and QoL. 1,4,6,18 Similarly, some children with single-sided deafness have obtained significant audiological and subjective benefits from cochlear implantation. 4,5,19 Unlike the contralateral routing of signal and BAHA devices, cochlear implantation helps patients with single-sided deafness obtain bilateral input and restores bilateral hearing, rather than simply transmitting sound signals to the normal ear.…”

Cochlear Implants in Patients with Fluctuant or Progressive Hearing Loss on the Better Ear

“…Many investigators feel that cochlear implants are superior to other devices, such as devices for contralateral routing of sound (CROS) and osseointegrated implants, for stimulating the deaf ear rather than send sounds to the opposite ear, but there are still some controversies in relation to these opinions. [2][3][4][5][6][7] According to Dillon et al, 8 cochlear implantation in cases of substantial hearing loss may offer significant improvements in the quality of life; quality of life measures revealed a reduction in perceived tinnitus severity and subjective improvements in speech perception in noise, spatial hearing, and listening effort.…”