Influence of factors related to electrode array placement on the early speech recognition of cochlear implant recipients with and without functional hearing preservation

Abstract

Cochlear implant (CI) and electric-acoustic stimulation (EAS) device users vary in their early speech recognition. This variability may be due in part to factors related to the electrode array placement, including frequency-to-place mismatch and the array's proximity to the functional acoustic hearing region. The present study reviewed the association of factors related to electrode array placement and early speech recognition in quiet and noise in CI and EAS users. The sample included 34 adults with preoperative thresholds at 250 Hz of ≤ 70 dB hearing level (HL) who were implanted with a 23-mm straight electrode array. For those who lost functional acoustic hearing and listened with a CI device ( n = 15), word recognition in quiet was significantly associated with frequency-to-place mismatch at 1.5 kHz, r (15) = 0.61, p = 0.015. For EAS users ( n = 18), 14 had their electrode arrays placed outside the functional acoustic hearing region, and 4 had electrodes in the functional acoustic hearing region. For EAS users with the array outside the functional acoustic hearing region, speech recognition in noise was not significantly associated with frequency-to-place mismatch, r (9) = 0.33, p = 0.389. Performance in noise was significantly associated with proximity, r (9) = 0.96, p < 0.001, with poorer scores for EAS users whose electrode arrays were placed farther from the functional acoustic hearing region. These preliminary data suggest that factors related to electrode array placement may contribute to the variability in early outcomes in CI and EAS users and may be important to consider in device selection and mapping to help individuals achieve their best outcomes.