Torres, Jennifer H.

Fourteen single-sided deaf listeners fit with an MED-EL cochlear implant (CI) judged the similarity of clean signals presented to their CI and modified signals presented to their normal-hearing ear. The signals to the normal-hearing ear were created by (a) filtering, (b) spectral smearing, (c) changing overall fundamental frequency (F0), (d) F0 contour flattening, (e) changing formant frequencies, (f) altering resonances and ring times to create a metallic sound quality, (g) using a noise vocoder, or (h) using a sine vocoder. The operations could be used singly or in any combination. On a scale of 1 to 10 where 10 was a complete match to the sound of the CI, the mean match score was 8.8. Over half of the matches were 9.0 or higher. The most common alterations to a clean signal were band-pass or low-pass filtering, spectral peak smearing, and F0 contour flattening. On average, 3.4 operations were used to create a match. Upshifts in formant frequencies were implemented most often for electrode insertion angles less than approximately 500°. A relatively small set of operations can produce signals that approximate the sound of the MED-EL CI. There are large individual differences in the combination of operations needed. The sound files in Supplemental Material approximate the sound of the MED-EL CI for patients fit with 28-mm electrode arrays.

Objectives/HypothesisTo report the preliminary outcomes of patients with single‐sided deafness and asymmetric hearing loss undergoing cochlear implantation at two centers.Study DesignRetrospective review and prospective data collection.MethodsPatients with single‐sided deafness who underwent cochlear implantation at two centers were included. Pre‐ and postoperative measures included monosyllabic word and sentence recognition in quiet for the ear implanted, and sentence recognition in noise in the best‐aided bilateral condition.ResultsAverage monosyllabic word recognition scores in quiet improved significantly from 11.3% (standard deviation [SD] 15.6%) preoperatively to 48.7% (SD 24.2%) at the 3‐month postactivation interval, although they did not increase significantly between the 3‐month and 6‐month intervals. Sentence recognition scores in quiet increased significantly from 18.4% (SD 28.5%) preoperatively to 65.9% (SD 17.9%) at the 3‐month postactivation interval, but not between the 3‐month and 6‐month intervals. Sentence recognition in noise in the best‐aided bilateral condition increased from 59% (SD 16.3%) preoperatively to 72% (SD 16.0%) at 6‐months postactivation, though the difference was not statistically significant. Thirteen of the participants reported tinnitus prior to surgery. Of those, 12 reported that tinnitus was improved after implantation, and one reported that tinnitus was unchanged.ConclusionPreliminary results suggest that speech recognition in a singly deafened ear is significantly improved after cochlear implantation, although speech recognition in noise measured in the bilateral condition remains the same at 6‐months postactivation.Level of Evidence4. Laryngoscope, 127:223–228, 2017