Audio-visual speechreading in a group of hearing aid users. The effects of onset age, handicap age, and degree of hearing loss.

Speechreading ability was investigated among hearing aid users with different time of onset and different degree of hearing loss. Audio-visual and visual-only performance were assessed. One group of subjects had been hearing-impaired for a large part of their lives, and the impairments appeared early in life. The other group of subjects had been impaired for a fewer number of years, and the impairments appeared later in life. Differences between the groups were obtained. There was no significant difference on the audio-visual test between the groups in spite of the fact that the early onset group scored very poorly auditorily. However, the early-onset group performed significantly better on the visual test. It was concluded that the visual information constituted the dominant coding strategy for the early onset group. An interpretation chiefly in terms of early onset may be the most appropriate, since dB loss variations as such are not related to speechreading skill.