Temporal and spatial characteristics of eye-gaze in speech perception
The long-term objective of this study is to understand the role of measurable visual processes in speechreading, a form of human information processing. Virtually all observers, and especially people with impaired hearing, rely on visual information in difficult listening situations. The specific aim of this study is to determine if particular observable visual processes relate to speechreading performance. An understanding of visual processes in speech perception has important implications for the design of sensory aids and development of research-based intervention protocols to augment speechreading performance.
Eye-monitoring techniques will be used to gain knowledge about where a person looks when trying to speechread and if looking behaviors are related to speechreading skill. Patterns of eye-gaze will be elicited with a sentence recognition task. Subjects will include five oral-deaf adults who demonstrate excellent speechreading performance and twenty individuals with hearing loss who differ in speechreading skill but must rely on visual speech perception in difficult listening situations. Eye-gaze behaviors will be interpreted with regard to the sequence, location, duration, and frequency of eye-movement associated with particular facial regions of a talker. Optic-flow analysis, an image processing technique to quantify the distribution of velocity changes associated with movements of an object, will be employed to quantify face movement for specific words that occur in the sentence-length utterances. The speechreaders' eye-gaze behavior will be studied in relation to the talker's face movements. The results of this study will be used to develop additional hypotheses regarding perceptual learning and rehabilitation strategies for individuals with hearing loss.