Comprehension of a sentence under a wide range of delay conditions between auditory and visual stimuli was measured
in the environment with low auditory clarity of the level of -10dB and -15dB pink noise. Results showed that the image
was helpful for comprehension of the noise-obscured voice stimulus when the delay between the auditory and visual
stimuli was 4 frames (=132msec) or less, the image was not helpful for comprehension when the delay between the
auditory and visual stimulus was 8 frames (=264msec) or more, and in some cases of the largest delay (32 frames), the
video image interfered with comprehension.