Impaired visual attention in children with dyslexia.
Reading involves the correct and rapid identification of visual stimuli with letters and words. The processing of visual stimuli depends not only on the integrity of the peripheral and central visual system but also on the attentional systems involved. In the present study, a cue-target visual attention task was administered to a population-based sample of 25 children with dyslexia from 10 to 12 years of age. A control group matched for group size, age, and gender was obtained from the same general population. A two-stage screening process involved a spelling task of regular words followed by a battery of five single-word reading tasks. The cue-target task involved both a computer-controlled stimulus presentation and a computer-controlled measurement of reaction time. The data were analyzed by visual field, cue condition (valid, invalid, and no cue), and cue-target interval (CTI). The results showed a general pattern of slower responses in the dyslexia group compared to the control group. The dyslexia group also had longer reaction times in the short CTI condition (covert shift of attention) and in the long CTI condition (overt shift of attention). The findings may reflect a general attentional deficit to visual stimuli in dyslexia, possibly related to problems with the recruitment of necessary cognitive resources for the performance of complex reaction time tasks and for fluent reading.
Heiervang
Einar
E
Department of Psychiatry, University of Bergen, Norway.
Hugdahl
Kenneth
K
D001288:Attention / Q000502:physiology*; D002648:Child; D003463:Cues; D004410:Dyslexia / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D011897:Random Allocation; D011930:Reaction Time / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*