The Effects of Simultaneous and Successive Tasks and Knowledge of Results on ADD and Non-ADD Children

Computerized continuous performance tasks (CPT) are often used to diagnose attention deficit disorders (ADD) The purpose of the present study was to continue the evaluation of a CPT developed from a psychophysical perspective. Specifically, two versions of a monitoring task (simultaneous and successive) were examined in the context of three conditions of knowledge of results (KR); KR to correct detections, false alarms, and irrelevant KR. Thirty children diagnosed with ADD and 30 without ADD performed two 9-minute monitoring tasks. Parents of the children were also interviewed with an adaptive behavior scale to investigate whether ADD children exhibit social functioning at a lower level than their same-age peers. The results showed that ADD children produce fewer correct detections but more false alarms, and exhibit lower sensitivity and more liberal responding than non-ADD children. Children with ADD also had lower age equivalent scores indicating that they have lower social functioning than their non-ADD peers. All children performed better on the successive as opposed to the simultaneous task. With respect to KR, none of the KR conditions had any appreciable effect on perceptual sensitivity. On the other hand, KR to false alarms resulted in more conservative responding than either KR to correct detections or irrelevant KR. Based on these results, it was concluded that the present version of the CPT is capable of differentiating between ADD and non- ADD children. Task type and KR type, however, contributed little to the distinction between these two groups of children. Other changes to the CPT are suggested which might bolster its ability to diagnose ADD in young children.