An FMRI auditory oddball study of combined-subtype attention deficit hyperactivity disorder.
OBJECTIVE
Studies of attention deficit hyperactivity disorder (ADHD) have reliably found reduced amplitude event-related potentials (ERPs) measuring attention-related brain function, indicating impairment in the brain's ability to automatically orient attention to odd or novel environmental stimuli and to represent that information in working memory. However, the relationship between abnormal neurocognition and dysfunction in specific brain regions in ADHD remains unclear.


METHODS
The authors used functional magnetic resonance imaging (fMRI) to identify brain regions with abnormal hemodynamic activity during processing of target and novelty oddball stimuli that engage attention. Forty-six boys 11-18 years of age participated in the study, including 23 diagnosed as having ADHD with hyperactivity and impulsivity (combined type) and 23 demographically matched control subjects. Event-related fMRI data were collected while participants performed a three-stimulus auditory oddball task. Hemodynamic activity was compared between ADHD participants and control subjects in brain regions previously linked to P3 ERPs.


RESULTS
Participants with ADHD showed deficits in brain activity elicited by infrequent attentionally engaging stimuli in regions associated with attentional orienting and working-memory cognitive processes. These deficits co-occurred with highly variable and slow task performance.


CONCLUSIONS
This study links ADHD attentional orienting and working-memory deficits to dysfunction in specific cortical brain regions. The results indicate that ADHD pathophysiology impairs brain systems that are important for allocating attention and using cognitive representations to guide cognition and behavior. Attention-related neural dysfunction is thus an important factor to consider in neurobiological theories of ADHD.
Stevens
Michael C
MC
Olin Neuropsychiatry Research Center, Whitehall Building, Institute of Living/Hartford Hospital, Hartford, CT 06106, USA. msteven@harthosp.org
Pearlson
Godfrey D
GD
Kiehl
Kent A
KA
D000161:Acoustic Stimulation; D000293:Adolescent; D000294:Adolescent Behavior / Q000502:physiology; D001288:Attention / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000175:diagnosis* / Q000503:physiopathology; D001307:Auditory Perception / Q000502:physiology*; D001921:Brain / Q000098:blood supply* / Q000502:physiology / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005071:Evoked Potentials; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000503:physiopathology; D009949:Orientation / Q000502:physiology; D010100:Oxygen / Q000097:blood; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology* / Q000528:radiation effects
D010100:Oxygen