Vision in lip positioning skills of children with normal and impaired hearing

Abstract

Interplay between visual feedback and lip and jaw positioning skill was studied in twenty 5‐ to 14‐year‐aid children with normal hearing, and with severe‐to‐profound hearing impairment. With visual feedback, the subjects in both groups were similar in response time and in accuracy of matching six visually specified lip separation “targets.” Special skill in processing visual information by the hearing‐impaired subjects was suggested by higher velocities in lip movements toward the targets and shorter latencies in reaching the goal positions. In the responses of the hearing children, lip‐closing movements were executed more accurately than opening movements, both with and without visual feedback. This was found only in the nonfeedback condition with the HI children, suggesting that the visual information had a greater effect on their responses. In general, the findings showed that, given visually displayed lip position targets and feedback from positioning actions, children can achieve them with high accuracy, regardless of hearing status or amount of prior speaking experience.