Ability of dyslexic and control teenagers to sustain attention and inhibitresponses

Dyslexia and attentional difficulty have often been linked, but little is k nown of the nature of the supposed attentional disorder. The Sustained Atte ntion to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) was designed as a measure of sustained attention and requires the wi thholding of responses to rare (one in nine) targets. To investigate the na ture of the attentional disorder in dyslexia, this paper reports two studie s that examined the performance of teenagers with dyslexia and their age-ma tched controls on the SART, the squiggle SART (a modification of the SART u sing novel and unlabellable stimuli rather than digits) and the go-gap-stop test of response inhibition (GGST). Teenagers with dyslexia made significa ntly more errors than controls on the original SART, but not on the squiggl e SART. There were no group differences on the GGST. After controlling for speed of reaction time in a sequential multiple regression predicting SART false alarms, false alarms on the GGST accounted for up to 22 per cent extr a variance in the control groups (although less on the squiggle SART) but n egligible amounts of variance in the dyslexic groups. We interpret the resu lts as reflecting a stimulus recognition automaticity der cit in dyslexia, rather than a sustained attention der cit. Furthermore, results suggest tha t response inhibition is an important component of performance on the stand ard SART when stimuli are recognised automatically.