title: Contribution of low-frequency acoustic information to Chinese speech recognition in cochlear implant simulations.
abstract: Chinese sentence recognition strongly relates to the reception of tonal information. For cochlear implant (CI) users with residual acoustic hearing, tonal information may be enhanced by restoring low-frequency acoustic cues in the nonimplanted ear. The present study investigated the contribution of low-frequency acoustic information to Chinese speech recognition in Mandarin-speaking normal-hearing subjects listening to acoustic simulations of bilaterally combined electric and acoustic hearing. Subjects listened to a 6-channel CI simulation in one ear and low-pass filtered speech in the other ear. Chinese tone, phoneme, and sentence recognition were measured in steady-state, speech-shaped noise, as a function of the cutoff frequency for low-pass filtered speech. Results showed that low-frequency acoustic information below 500 Hz contributed most strongly to tone recognition, while low-frequency acoustic information above 500 Hz contributed most strongly to phoneme recognition. For Chinese sentences, speech reception thresholds (SRTs) improved with increasing amounts of low-frequency acoustic information, and significantly improved when low-frequency acoustic information above 500 Hz was preserved. SRTs were not significantly affected by the degree of spectral overlap between the CI simulation and low-pass filtered speech. These results suggest that, for CI patients with residual acoustic hearing, preserving low-frequency acoustic information can improve Chinese speech recognition in noise.
authors.affiliation: Department of Auditory Implants and Perception, House Ear Institute, 2100 West Third Street, Los Angeles, California 90057, USA. xluo@hei.org
authors.forename: Xin
authors.initials: X
authors.lastname: Luo
authors.forename: Qian-Jie
authors.initials: QJ
authors.lastname: Fu
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000704:Analysis of Variance; D003054:Cochlear Implants; D003198:Computer Simulation; D004558:Electric Stimulation / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D013061:Speech Acoustics; D013067:Speech Perception / Q000502:physiology*; D013069:Speech Reception Threshold Test