title: Loudness Contour Can Influence Mandarin Tone Recognition: Vocoder Simulation and Cochlear Implants.
abstract: Lexical tone recognition with current cochlear implants (CI) remains unsatisfactory due to significantly degraded pitch-related acoustic cues, which dominate the tone recognition by normal-hearing (NH) listeners. Several secondary cues (e.g., amplitude contour, duration, and spectral envelope) that influence tone recognition in NH listeners and CI users have been studied. This work proposes a loudness contour manipulation algorithm, namely Loudness-Tone (L-Tone), to investigate the effects of loudness contour on Mandarin tone recognition and the effectiveness of using loudness cue to enhance tone recognition for CI users. With L-Tone, the intensity of sound samples is multiplied by gain values determined by instantaneous fundamental frequencies (F0s) and pre-defined gain- F0 mapping functions. Perceptual experiments were conducted with a four-channel noise-band vocoder simulation in NH listeners and with CI users. The results suggested that 1) loudness contour is a useful secondary cue for Mandarin tone recognition, especially when pitch cues are significantly degraded; 2) L-Tone can be used to improve Mandarin tone recognition in both simulated and actual CI-hearing without significant negative effect on vowel and consonant recognition. L-Tone is a promising algorithm for incorporation into real-time CI processing and off-line CI rehabilitation training software.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Meng
authors.forename: Nengheng
authors.initials: N
authors.lastname: Zheng
authors.forename: Xia
authors.initials: X
authors.lastname: Li
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000293:Adolescent; D000328:Adult; D001307:Auditory Perception; D002681:China; D003054:Cochlear Implants; D003463:Cues; D003638:Deafness / Q000175:diagnosis / Q000503:physiopathology* / Q000534:rehabilitation*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D010898:Pitch Perception; D013018:Sound Spectrography / Q000379:methods*; D013067:Speech Perception; D055815:Young Adult