Children with hearing loss have a wide range of spoken language outcomes. The source of this variability is not fully understood because little is known about language acquisition strategies in this population. Typical language development in hearing infants is dependent on infants' ability to coordinate their visual attention with that of their caregivers, whereby the dyad shares attention (i.e., visual joint attention) on an object or event in their environment. Congenital hearing loss interferes with this behavior: infants with hearing loss spend more time looking at their caregivers and less time in visual joint attention. A gap in knowledge is whether infants with hearing loss deploy their visual attention to their caregivers (as opposed to objects) during social interactions to gather linguistic information from visual speech cues. Increased visual attention to talkers in infancy may lead to enhanced audiovisual speech perception and better comprehension of linguistic content. Alternatively, it may impair typical language acquisition strategies that rely on increased visual attention to objects and events. Consistent with a poor understanding of these processes, current language interventions for children with hearing loss differ widely in their emphasis on visual speech cues. The long-term goal of this research program is to understand how hearing loss influences visual attention to talkers in infancy and audiovisual speech perception in childhood. The proposed longitudinal study will test the hypotheses that childhood hearing loss (1) promotes increased visual attention to talkers during social interactions in infancy; and (2) hastens the development of audiovisual speech perception. Participants will be 126 children (N = 63 with bilateral sensorineural hearing loss; N = 63 with normal hearing) who will be recruited between 9-18 months of age and tested bi-annually for two years.
Aim 1 will test whether infants with hearing loss exhibit increased visual attention to talkers using both a structured interactional paradigm and preferential looking paradigm.
Aim 2 will test whether visual attention to talkers persists in children with hearing loss, providing an advantage in audiovisual speech perception. An experimental set-up integrating eye-tracking and touch-screen data will be implemented in quiet and in the presence of a speech masker to quantify individual differences in audiovisual speech perception over the course of the two-year study.
Aim 3 will test whether visual attention to talkers in infancy predicts audiovisual speech perception and spoken language outcomes in early childhood through the implementation of longitudinal statistical analyses. Statistical analyses will also test whether audiovisual speech perception predicts spoken language outcomes, directly and by mediating the predictive power of visual attention. The proposed study will address a critical gap in our understanding of how audiovisual speech perception emerges in early childhood, how it is influenced by hearing experience, and how it relates to spoken language development. Results from this work will lead to evidence-driven clinical decisions for young children with hearing loss.
Children with hearing loss have reduced access to sound, putting them at risk for spoken language delays. Interventions for these children differ widely in the utilization of visual speech cues despite the known perceptual benefit of concomitant hearing and seeing speech. The proposed study aims to define the relation between visual attention to talkers in infancy, audiovisual speech perception, and spoken language development, which will inform evidence-driven intervention programs for children with hearing loss.
