Spatial Release From Masking in Adults With Bilateral Cochlear Implants: Effects of Distracter Azimuth and Microphone Location

• Published in: Journal of speech, language, and hearing research Vol. 61; no. 3; pp. 752 - 761
• Main Authors: Davis, Timothy J., Gifford, René H.
• Format: Journal Article
• Language: English
• Published: United States American Speech-Language-Hearing Association 01.03.2018
• Subjects: Adult; Adults; Aged; Aged, 80 and over; Assistive Technology; Audiology; Auditory system; Cochlear Implants; Coding; Cues; Deafness; Deafness - psychology; Deafness - rehabilitation; Ears & hearing; Female; Hearing; Hearing Impairments; Hearing loss; Human Body; Humans; Listening comprehension; Male; Masking; Measurement; Microphones; Middle Aged; Noise; Patient outcomes; Pattern Recognition, Physiological; Perceptual Masking; Psychoacoustics; Research Design; Signal processing; Speech; Speech Communication; Speech Improvement; Speech Perception; Speech recognition; Stimuli; Transplants & implants
• DOI: 10.1044/2017_JSLHR-H-16-0441
• ISSN: 1092-4388; 1558-9102

Purpose: The primary purpose of this study was to derive spatial release from masking (SRM) performance-azimuth functions for bilateral cochlear implant (CI) users to provide a thorough description of SRM as a function of target/distracter spatial configuration. The secondary purpose of this study was to investigate the effect of the microphone location for SRM in a within-subject study design. Method: Speech recognition was measured in 12 adults with bilateral CIs for 11 spatial separations ranging from -90° to +90° in 20° steps using an adaptive block design. Five of the 12 participants were tested with both the behind-the-ear microphones and a T-mic configuration to further investigate the effect of mic location on SRM. Results: SRM can be significantly affected by the hemifield origin of the distracter stimulus--particularly for listeners with interaural asymmetry in speech understanding. The greatest SRM was observed with a distracter positioned 50° away from the target. There was no effect of mic location on SRM for the current experimental design. Conclusion: Our results demonstrate that the traditional assessment of SRM with a distracter positioned at 90° azimuth may underestimate maximum performance for individuals with bilateral CIs.