Impact of High- and Low-Pass Acoustic Filtering on Audiovisual Speech Redundancy and Benefit in Children

For isolated word recognition, visual speech is more complementary with the acoustic speech cues children can access when high-frequency acoustic content is eliminated by low-pass filtering than when low-frequency acoustic content is eliminated by high-pass filtering. This decreased auditory-visual phonetic redundancy is accompanied by larger audiovisual benefit. In contrast, audiovisual benefit for sentence recognition did not differ between low-pass and high-pass filtered speech. This might reflect ceiling effects in audiovisual conditions or a decrease in the contribution of auditory-visual phonetic redundancy to explaining audiovisual benefit for connected speech. These results from children with typical hearing suggest that some variance in audiovisual benefit among children who are hard of hearing may depend in part on frequency-specific audibility.