HSC Section 8_April 2017

Fig. 1. Preoperative air conduction hearing thresholds for the implanted ear.

The emerging research is positive and suggests that CIs offer partial hearing restoration for the implanted ear, although outcomes related to binaural hearing are mixed. Speech recognition in the ear implanted, when measured in quiet, has been shown to improve signifi- cantly following implantation. 10,11 Speech recognition in noise, however, is highly variable and test parameters vary considerably among investigators, making direct comparison difficult. For example, Vermiere, Tavora- Viera, and Stelzig each presented speech and noise from a front center speaker (S0N0) and used an adaptive pro- cedure to find the signal-to-noise ratio (SNR) needed for 50% correct, although speech materials varied among them. 10,12,13 Vermiere et al. found a statistically signifi- cant decrease in the SNR needed for sentence under- standing, and the other two did not. 10 Later, a meta- analysis pooling all three studies demonstrated a mean decrease in SNR necessary for 50% correct. 14 In other research, Stelzig et al. and Arndt et al. each presented speech and noise at 65-dB sound pressure level (SPL) from S0N0 and found no difference in sentence recogni- tion following cochlear implantation. 13,15 Zeitler et al. showed subjects undergoing CI for SSD demonstrated significant improvement in sentence scores in complex noise environments in the binaural condition, with the greatest improvements when speech is presented to the implanted ear. These same subjects also showed signifi- cant improvements in sound source localization, with some subjects localizing sound at or near the accuracy of normal hearing listeners. 16 Other studies have also reported significant improvement for localization among patients with SSD, decreased tinnitus, and improved self-perceived benefit on the Speech Spatial and Qual- ities of Hearing questionnaire. 17 Reports of tinnitus suppression after implantation have been reported by several investigators. 15,18 In one study, Arts et al. examined the impact of implantation on tinnitus among patients with SSD by pooling data from several reports. 18 The data were treated as a multi- center study and subjected to matched t tests. Results demonstrated improved tinnitus between preoperative and 1-, 3-, 6-, and 24- month postoperative test intervals.

The purpose of this study was to complete a preliminary evaluation of speech recognition in quiet and in noise among a group of adults and children with SSD. Data was compiled from two separate centers. MATERIALS AND METHODS The current study was a multisite, single-arm repeated measures research design. Each participating center obtained institutional review board approval from their respective center. Participants The participants in this study had mild to severe sensori- neural hearing loss with 40% consonant-nucleus-consonant (CNC) word recognition on the affected side. A pure tone aver- age of 30 dB HL or better and a mean word recognition score of 99.3% (standard deviation [SD] 2.8%) were present on the con- tralateral side. Thus, all patients had truly normal hearing in the nonimplanted ear. The preoperative air conduction hearing thresholds for the ear implanted can be found in Figure 1. The total sample was comprised of 23 individuals (17 adults, 6 children). The adults ranged in age from 31 to 62 years, and the children ranged in age from 5 to 15 years. Dura- tion of hearing loss was defined as the time between onset of hearing loss and time of implantation. Duration of hearing loss ranged from 0.5 to 9.5 years with an average of 4.0 years. In all, there were 10 left ears and 13 right ears implanted. Demo- graphic information for all participants can be found in Table I. Materials Speech understanding was assessed using the CNC word test and the AzBio sentence test. 19,20 The CNC word test is com- prised of 10 lists, each containing 50 monosyllabic words produced by a single male talker. The AzBio Sentence Test is comprised of 15 lists of 20 sentences, each produced by two male and two female talkers and scored for each word repeated correctly. Procedures Prior to preoperative aided testing, participants’ hearing aids were set to National Acoustic Laboratories (prescriptive targets). 21 Participants who did not use hearing aids on a full- time basis were required to complete a 30-day trial before CI candidacy determination.

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