title: Event-related potentials for better speech perception in noise by cochlear implant users.
abstract: Speech perception in noise is still difficult for cochlear implant (CI) users even with many years of CI use. This study aimed to investigate neurophysiological and behavioral foundations for CI-dependent speech perception in noise. Seventeen post-lingual CI users and twelve age-matched normal hearing adults participated in two experiments. In Experiment 1, CI users' auditory-only word perception in noise (white noise, two-talker babble; at 10 dB SNR) degraded by about 15%, compared to that in quiet (48% accuracy). CI users' auditory-visual word perception was generally better than auditory-only perception. Auditory-visual word perception was degraded under information masking by the two-talker noise (69% accuracy), compared to that in quiet (77%). Such degradation was not observed for white noise (77%), suggesting that the overcoming of information masking is an important issue for CI users' speech perception improvement. In Experiment 2, event-related cortical potentials were recorded in an auditory oddball task in quiet and noise (white noise only). Similarly to the normal hearing participants, the CI users showed the mismatch negative response (MNR) to deviant speech in quiet, indicating automatic speech detection. In noise, the MNR disappeared in the CI users, and only the good CI performers (above 66% accuracy) showed P300 (P3) like the normal hearing participants. P3 amplitude in the CI users was positively correlated with speech perception scores. These results suggest that CI users' difficulty in speech perception in noise is associated with the lack of automatic speech detection indicated by the MNR. Successful performance in noise may begin with attended auditory processing indicated by P3.
authors.affiliation: Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, 2-40-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Soshi
authors.affiliation: Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, 2-40-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Hisanaga
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan.
authors.forename: Narihiro
authors.initials: N
authors.lastname: Kodama
authors.affiliation: Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, 2-40-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
authors.forename: Yori
authors.initials: Y
authors.lastname: Kanekama
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Samejima
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Yumoto
authors.affiliation: Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, 2-40-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan. Electronic address: sekiyama@kumamoto-u.ac.jp.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sekiyama
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001307:Auditory Perception; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003071:Cognition; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006309:Hearing; D006801:Humans; D007564:Japan; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009482:Neurophysiology; D009622:Noise; D011788:Quality of Life; D015203:Reproducibility of Results; D013067:Speech Perception / Q000502:physiology*