title: Effects of Visual Speech on Early Auditory Evoked Fields - From the Viewpoint of Individual Variance.
abstract: The effects of visual speech (the moving image of the speaker's face uttering speech sound) on early auditory evoked fields (AEFs) were examined using a helmet-shaped magnetoencephalography system in 12 healthy volunteers (9 males, mean age 35.5 years). AEFs (N100m) in response to the monosyllabic sound /be/ were recorded and analyzed under three different visual stimulus conditions, the moving image of the same speaker's face uttering /be/ (congruent visual stimuli) or uttering /ge/ (incongruent visual stimuli), and visual noise (still image processed from speaker's face using a strong Gaussian filter: control condition). On average, latency of N100m was significantly shortened in the bilateral hemispheres for both congruent and incongruent auditory/visual (A/V) stimuli, compared to the control A/V condition. However, the degree of N100m shortening was not significantly different between the congruent and incongruent A/V conditions, despite the significant differences in psychophysical responses between these two A/V conditions. Moreover, analysis of the magnitudes of these visual effects on AEFs in individuals showed that the lip-reading effects on AEFs tended to be well correlated between the two different audio-visual conditions (congruent vs. incongruent visual stimuli) in the bilateral hemispheres but were not significantly correlated between right and left hemisphere. On the other hand, no significant correlation was observed between the magnitudes of visual speech effects and psychophysical responses. These results may indicate that the auditory-visual interaction observed on the N100m is a fundamental process which does not depend on the congruency of the visual information.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Yahata
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.|Laboratory of Rehabilitative Auditory Science, Tohoku University Graduate School of Biomedical Engineering, Sendai, Miyagi, Japan.|Department of Audiology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Tetsuaki
authors.identifier: http://orcid.org/0000-0001-5100-7331
authors.initials: T
authors.lastname: Kawase
authors.affiliation: Department of Functional Brain Imaging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Akitake
authors.initials: A
authors.lastname: Kanno
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hidaka
authors.affiliation: Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sakamoto
authors.affiliation: Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Nakasato
authors.affiliation: Department of Functional Brain Imaging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Kawashima
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Katori
mesh_terms: D000328:Adult; D054022:Cerebrum / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008085:Lipreading; D015225:Magnetoencephalography; D008297:Male; D011930:Reaction Time; D013060:Speech / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D058067:Wavelet Analysis