Visual evoked-response components related to speechreading and spatial skills in hearing and hearing-impaired adults

Averaged visual evoked responses (VER) to light flashes which varied systematically in brightness and predictability were collected from 24 hearing and 24 hearing-impaired adults. In addition, speechreading, abstract reasoning, and spatial relations tests were administered. Separate principal components analyses of the VERs were conducted on each group to replicate and extend our previous report of an early VER component (VF16) which reflected individual differences in the speechreading skills of hearing subjects. VF16 appeared in both analyses, confirming its replicability as a latent VER component. VF16 correlated with speechreading skill in hearing-impaired males (r = -.73), under stimulus conditions identical to those in our previous study. However, its correlations with speechreading skills in hearing subjects were not significant. VF16 also varied systematically with stimulus predictability and correlated with spatial ability in both groups only when the time of occurrence of the light flashes was predictable. These data tentatively suggest that VF16 is a VER correlate of individual differences in a psychologically dynamic process, perhaps involving expectancy, which may relate to the performance of hearing-impaired and hearing people in visually based communication or cognitive processing situations.