Doctoral Dissertations

Date of Award

8-1996

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Education

Major Professor

Teresa A. Hutchens

Committee Members

William A. Poppen, Harold Peterson, Joel Lubar

Abstract

Continuous performance tests (CPT) have been used in investigations of sustained attention in diverse clinical samples. Such groups have included those described by traumatic brain injury (Rosvold, Mirsky, Sarason, Bransome, & Beck, 1956), schizophrenia, (Cornblatt and Erlenmeyer-Kimling, 1985; Nuechterlein, 1983) learning disabilities (Beale, Matthew, Oliver, & Corballis, 1987; Eliason and Richman, 1988; and Swanson, 1983), and Attention Deficit-Hyperactivity Disorder (Tannock, Schachar, Carr, Chajczyk, & Logan, 1989). Sustained attention, as measured by the CPT, has been shown to be compromised in individuals characterized by each of these conditions. The present study used the Conners' (1994) Continuous Performance Test (CCPT) to more closely compare response characteristics within this paradigm. Three groups of children were sampled, the learning disabled (LD), those with Attention-Deficit/Hyperactivity Disorder (ADHD), and children with no disability as a control (NC). Subjects were drawn from a public school system and matched for age, gender, and mental ability. The groups' performances on the CCPT were compared for different qualities found within measures of response latency and accuracy. Each of these variables relate to three constructs which are diagnostically relevant in LD and ADHD: impulsivity, sustained attention, and selective attention. It was predicted that the ADHD group would exhibit a higher response speed and greater frequency of responding to reflect greater impulsivity. This research question was not supported by the data. Groups were different for only one of three variables related to this question. Beta, a statistical analogue reflecting frequency of responding was different for the three groups (p < .01), but the single statistically significant difference between groups was in the opposite direction expected. The ADHD group responded more frequently than the NC group (p < .01). The ADHD group was also predicted to exhibit poorer sustained attention than the other two groups, as manifested by changes and variability in response latency. Significant differences between groups were found for four out of five CCPT measures, regarding overall response time variability (p < .01), response time change as a function of time on task (p < .05), response time change as a function of time between targets (p < .05), and response time variability as a function of time between targets (p < .05). analyses found all inter group differences to be in the Post hoc direction expected. The ADHD group exceeded both the LD group (p < .05) and the NC group (p < .01) for overall response time variability; the ADHD group exceeded only the NC group (p < .05) for response time change as a function of time on task; the ADHD group exceeded both the LD group (p < .05) and the NC group (p < .05) for response time change as a function of time between targets; and the ADHD group exceeded only the NC group (p < .05) for response time variability as a function of time between targets. Finally, it was predicted that the LD group would exhibit poorer selective attention than the ADHD or NC groups as manifested by two measures of target discrimination. The data did not support this research question. While there were significant differences between groups for both omissions (p < .01) and D-prime, a statistical analogue of target discrimination (p < .01), the differences were in the opposite direction expected. Post hoc analyses found the ADHD group to have more omission errors than both the LD (e < .01) and the NC (p < .01) groups; the ADHD group was found to have poorer target discrimination (D-prime) than only the NC group (p < .01) This research yields implications for differentiation LD and ADHD subjects. These results suggests that inattention and processing speed may be more salient characteristics of ADHD subjects than impulsivity. Measures of response latency discriminated ADHD subjects better than response accuracy, confirming the role of inattention.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS