Journal Article


Ian H Robertson
Michael Gill
Marie Cox
Edwina Barry
Mark A. Bellgrove
Simon P Kelly
Katherine A. Johnson



humans reaction time psychomotor performance adolescent child female neuropsychological tests psychology diagnosis pattern recognition visual psychometrics analysis of variance attention deficit disorder with hyperactivity statistics numerical data reference values male linear models attention fourier analysis

Response variability in attention deficit hyperactivity disorder: evidence for neuropsychological heterogeneity. (2005)

Abstract Response time (RT) variability is a common finding in ADHD research. RT variability may reflect frontal cortex function and may be related to deficits in sustained attention. The existence of a sustained attention deficit in ADHD has been debated, largely because of inconsistent evidence of time-on-task effects. A fixed-sequence Sustained Attention to Response Task (SART) was given to 29 control, 39 unimpaired and 24 impaired-ADHD children (impairment defined by the number of commission errors). The response time data were analysed using the Fast Fourier Transform, to define the fast-frequency and slow-frequency contributions to overall response variability. The impaired-ADHD group progressively slowed in RT over the course of the 5.5min task, as reflected in this group's greater slow-frequency variability. The fast-frequency trial-to-trial variability was also significantly greater, but did not differentially worsen over the course of the task. The higher error rates of the impaired-ADHD group did not become differentially greater over the length of the task. The progressive slowing in mean RT over the course of the task may relate to a deficit in arousal in the impaired-ADHD group. The consistently poor performance in fast-frequency variability and error rates may be due to difficulties in sustained attention that fluctuate on a trial-to-trial basis.
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Full list of authors on original publication

Ian H Robertson, Michael Gill, Marie Cox, Edwina Barry, Mark A. Bellgrove, Simon P Kelly, Katherine A. Johnson

Experts in our system

Ian H Robertson
Trinity College Dublin
Total Publications: 162
Michael Gill
Trinity College Dublin
Total Publications: 294
Mark A. Bellgrove
Trinity College Dublin
Total Publications: 39
Simon P Kelly
University College Dublin
Total Publications: 48
Katherine Johnson
Trinity College Dublin
Total Publications: 29