Task-Specific Hypoactivation in Prefrontal and Temporoparietal Brain Regions During Motor Inhibition and Task Switching in Medication-Naive Children and Adolescents With Attention Deficit Hyperactivity Disorder

Anna B. Smith, Ph.D., Eric Taylor, M.D., Ph.D., Mick Brammer, Ph.D., Brian Toone, M.D. and Katya Rubia, Ph.D.

OBJECTIVE: A relatively small number of functional imaging studies of attention deficit hyperactivity disorder (ADHD) have shown abnormal prefrontal and striatal brain activation during tasks of motor response inhibition.

However, the potential confound of previous medication exposure has not yet been addressed, and no functional imaging study exists to date on medication-naive children and adolescents with ADHD. Read more of the article...

Researchers see flaws in brain-imaging studies

Insight on the News, August 19, 2003
by Kelly Patricia O'Meara

A recent review by Jonathan Leo, professor of anatomy at the Western University of Health Sciences in Pomona, Calif., and professor David Cohen of the School of Social Work at Florida International University in Miami, dispels the myth of brain imaging as a way to diagnose ADHD. And it finds that the majority of studies dating back to 1978 failed, unaccountably, to consider a major variable the use of psychotropic drugs by participants in the studies. Read more of the article...

Confirmation of an Inhibitory Control Deficit in Attention-Deficit/Hyperactivity Disorder.

Author/s: Russell Schachar
Issue: June, 2000

The objective of this study was to determine whether deficient inhibitory control distinguishes children with a diagnosis of attention-deficit/hyperactivity (ADHD) disorder, conduct disorder (CD), and comorbid ADHD + CD from normally developing children.

Participants were rigorously diagnosed children (age 7 to 12 years) with ADHD (N = 72), CD (N = 13) or ADHD + CD (N = 47) and 33 control children (NC). We studied inhibitory control using the stop-signal paradigm, a laboratory task that assessed the ability to inhibit an ongoing action. Read more of the article...

Task Switching and Attention Deficit Hyperactivity Disorder.

Author/s: Nicholas J. Cepeda Issue: June, 2000

The main goal of the present set of studies was to examine the efficiency of executive control processes and, more specifically, the control processes involved in task set inhibition and preparation to perform a new task in attention deficit hyperactivity disorder (ADHD) and non-ADHD children.

This was accomplished by having ADHD children, both on and off medication, and non-ADHD children perform the task-switching paradigm, which involves the performance of two simple tasks. Read more of the article...

Naming Speed Performance and Stimulant Effects Indicate Effortful, Semantic Processing Deficits in Attention-Deficit/Hyperactivity Disorder.

Author/s: Rosemary Tannock Issue: June, 2000
Rosemary Tannock [1,2] Rhonda Martinussen [1] Jan Frijters [1]

This study investigated rapid automatized naming and effects of stimulant medication in school-age children with attention-deficit/hyperactivity disorder (ADHD) with and without concurrent reading disorder (RD). Read more of the article...