Gifford, René H.

ObjectiveTo evaluate the use of monosyllabic word recognition versus sentence recognition to determine candidacy and long‐term benefit for cochlear implantation.Study DesignProspective multi‐center single‐subject design.MethodsA total of 21 adults aged 18 years and older with bilateral moderate to profound sensorineural hearing loss and low monosyllabic word scores received unilateral cochlear implantation. The consonant‐nucleus‐consonant (CNC) word test was the central measure of pre‐ and postoperative performance. Additional speech understanding tests included the Hearing in Noise Test sentences in quiet and AzBio sentences in +5 dB signal‐to‐noise ratio (SNR). Quality of life (QoL) was measured using the Abbreviated Profile of Hearing Aid Benefit and Health Utilities Index.ResultsPerformance on sentence recognition reached the ceiling of the test after only 3 months of implant use. In contrast, none of the participants in this study reached a score of 80% on CNC word recognition, even at the 12‐month postoperative test interval. Measures of QoL related to hearing were also significantly improved following implantation.ConclusionResults of this study demonstrate that monosyllabic words are appropriate for determining preoperative candidate and measuring long‐term postoperative speech recognition performance.Level of Evidence2c. Laryngoscope, 127:2368–2374, 2017

ObjectivesTo analyze factors that influence hearing preservation over time in cochlear implant recipients with conventional‐length electrode arrays located entirely within the scala tympani.Study DesignCase series with planned chart review.SettingSingle tertiary academic referral center.Subjects and MethodsA retrospective review was performed to analyze a subgroup of cochlear implant recipients with residual acoustic hearing. Patients were included in the study only if their electrode arrays remained fully in the scala tympani after insertion and serviceable acoustic hearing (≤80 dB at 250 Hz) was preserved. Electrode array location was verified through a validated radiographic assessment tool. Patients with <6 months of audiologic follow‐up were excluded. The main outcome measure was change in acoustic hearing thresholds from implant activation to the last available follow‐up.ResultsA total of 16 cases met inclusion criteria (median age, 70.6 years; range, 29.4‐82.2; 50% female). The average follow‐up was 18.0 months (median, 16.1; range, 6.2‐36.4). Patients with a lateral wall electrode array were more likely to have stable acoustic thresholds over time (P <. 05). Positive correlations were seen between continued hearing loss following activation and larger initial postoperative acoustic threshold shifts, though statistical significance was not achieved. Age, sex, and noise exposure had no significant influence on continued hearing preservation over time.ConclusionsTo control for hearing loss associated with interscalar excursion during cochlear implantation, the present study evaluated patients only with conventional electrode arrays located entirely within the scala tympani. In this group, the style of electrode array may influence residual hearing preservation over time.

In the newest implementation of cochlear implant surgery, electrode arrays of 10 or 20mm are inserted into the cochlea with the aim of preserving hearing in the region apical to the tip of the electrode array. In the current study two measures were used to assess hearing preservation: changes in audiometric threshold and changes in psychophysical estimates of nonlinear cochlear processing. Nonlinear cochlear processing was evaluated at signal frequencies of 250 and 500Hz using Schroeder phase maskers with various indices of masker phase curvature. A total of 15 normal-hearing listeners and 13 cochlear implant patients (7 with a 10mm insertion and 6 with a 20mm insertion) were tested. Following surgery the mean low-frequency threshold elevation was 12.7dB (125–750Hz). Nine patients had postimplant thresholds within 5–10dB of preimplant thresholds. Only one patient, however, demonstrated a completely normal nonlinear cochlear function following surgery—although most retained some degree of residual nonlinear processing. This result indicates (i) that Schroeder phase masking functions are a more sensitive index of surgical trauma than audiometric threshold and (ii) that preservation of a normal cochlear function in the apex of the cochlea is relatively uncommon but possible.