Evaluation of Automatic Directional Processing with Cochlear Implant Recipients

Abstract

Abstract Background For cochlear implant (CI) recipients, speech recognition in noise is consistently poorer compared with recognition in quiet. Directional processing improves performance in noise and can be automatically activated based on acoustic scene analysis. The use of adaptive directionality with CI recipients is new and has not been investigated thoroughly, especially utilizing the recipients' preferred everyday signal processing, dynamic range, and/or noise reduction. Purpose This study utilized CI recipients' preferred everyday signal processing to evaluate four directional microphone options in a noisy environment to determine which option provides the best speech recognition in noise. A greater understanding of automatic directionality could ultimately improve CI recipients' speech-in-noise performance and better guide clinicians in programming. Study Sample Twenty-six unilateral and seven bilateral CI recipients with a mean age of 66 years and approximately 4 years of CI experience were included. Data Collection and Analysis Speech-in-noise performance was measured using eight loudspeakers in a 360-degree array with HINT sentences presented in restaurant noise. Four directional options were evaluated (automatic [SCAN], adaptive [Beam], fixed [Zoom], and Omni-directional) with participants' everyday use signal processing options active. A mixed-model analysis of variance (ANOVA) and pairwise comparisons were performed. Results Automatic directionality (SCAN) resulted in the best speech-in-noise performance, although not significantly better than Beam. Omni-directional performance was significantly poorer compared with the three other directional options. A varied number of participants performed their best with each of the four-directional options, with 16 performing best with automatic directionality. The majority of participants did not perform best with their everyday directional option. Conclusion The individual variability seen in this study suggests that CI recipients try with different directional options to find their ideal program. However, based on a CI recipient's motivation to try different programs, automatic directionality is an appropriate everyday processing option.