Multi-microphone adaptive noise reduction strategies for coordinated stimulation in bilateral cochlear implant devices

• DOI: 10.1121/1.3372727
• Publication Date: 2010-05-13T21:47:47Z
• Authors: Kostas Kokkinakis; Philipos C. Loizou
• Keywords: Adult; Male; 610; Prosthesis Design; Vibration; 01 natural sciences; Speech Acoustics; 0103 physical sciences; Speech; Humans; Correction of Hearing Impairment; Aged; Acoustic beamforming; Speech Intelligibility; Signal Processing, Computer-Assisted; Middle Aged; Cochlear Implantation; Cochlear Implants; Acoustic Stimulation; Cochlear implants; Speech Perception; Female; Microphones; Audiometry, Speech; Comprehension; Noise; Acoustic noise; Perceptual Masking

Bilateral cochlear implant (BI-CI) recipients achieve high word recognition scores in quiet listening conditions. Still, there is a substantial drop in speech recognition performance when there is reverberation and more than one interferers. BI-CI users utilize information from just two directional microphones placed on opposite sides of the head in a so-called independent stimulation mode. To enhance the ability of BI-CI users to communicate in noise, the use of two computationally inexpensive multi-microphone adaptive noise reduction strategies exploiting information simultaneously collected by the microphones associated with two behind-the-ear (BTE) processors (one per ear) is proposed. To this end, as many as four microphones are employed (two omni-directional and two directional) in each of the two BTE processors (one per ear). In the proposed two-microphone binaural strategies, all four microphones (two behind each ear) are being used in a coordinated stimulation mode. The hypothesis is that such strategies combine spatial information from all microphones to form a better representation of the target than that made available with only a single input. Speech intelligibility is assessed in BI-CI listeners using IEEE sentences corrupted by up to three steady speech-shaped noise sources. Results indicate that multi-microphone strategies improve speech understanding in single- and multi-noise source scenarios.