Heart rate and reinforcement sensitivity in ADHD.
BACKGROUND
Both theoretical and clinical accounts of attention-deficit/hyperactivity disorder (ADHD) implicate a dysfunctional reinforcement system. This study investigated heart rate parameters in response to feedback associated with reward and response cost in ADHD children and controls aged 8 to 12.


METHODS
Heart rate responses (HRRs) following feedback and heart rate variability (HRV) in the low frequency band (.04-.08 Hz), a measure of mental effort, were calculated during a time production paradigm. Performance was coupled to monetary gain, loss or feedback-only in a cross-over design.


RESULTS
Children with ADHD exhibited smaller HRRs to feedback compared to controls. HRV of children with ADHD decreased when performance was coupled to reward or response cost compared to feedback-only. HRV of controls was similar across conditions.


CONCLUSIONS
Children with ADHD were characterised by (a) possible abnormalities in feedback monitoring and (b) motivational deficits, when no external reinforcement is present.
Luman
Marjolein
M
Department of Clinical Neuropsychology, Vrije Universiteit Amsterdam, The Netherlands.
Oosterlaan
Jaap
J
Hyde
Christopher
C
van Meel
Catharina S
CS
Sergeant
Joseph A
JA
D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D002648:Child; D018592:Cross-Over Studies; D005246:Feedback; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D012054:Reinforcement, Psychology; D012201:Reward; D013997:Time Factors