Controlled processing and vigilance in hyperactivity: time will tell.

This paper reviews the concept of sustained attention, placing it within a theoretical framework in which deficits of attention are conceived of as deficits of controlled information processing. Two types of deficit of sustained attention are distinguished: perceptual sensitivity and perceptual criterion. These two deficits are linked to a model of human performance that links controlled processes to the energetic pools: arousal and activation. Perceptual sensitivity (d') deficits are said to reflect arousal deficiencies, especially when observed in the early period of a vigil. Perceptual criterion deficits are associated with the activation pool and the response criterion measure beta. Despite clear evidence of perceptual deficiency in the hyperactive children to a greater extent than in the control group, and that performance in d' declined with time on task, a significant interaction failed to occur between group classification and time on task. Thus, the results failed to support the hypothesis of a sustained attention deficit in hyperactives, since if hyperactives have a sustained attention deficit, both d' and beta should have shown a significantly greater decline in the hyperactive group than in the controls with time on task.