Associations between event-related potentials and measures of attention and inhibition in the Continuous Performance Task in children with ADHD and normal controls.
OBJECTIVE
First, to differentiate between inattention and impulsivity based on type of errors made in the AX version of the Continuous Performance Task (CPT), and second, to investigate whether differences in performance between children with attention-deficit hyperactivity disorder (ADHD) and normal controls also occur in specific forms of brain activity, namely event-related potentials (ERPs), presumably related to inattention and impulsivity or inhibition.


METHODS
Sixteen ADHD and 16 normal control children performed the CPT-AX. ERPs were recorded at occipital (Oz), parietal (Pz), central (Cz), and frontal (Fz) leads.


RESULTS
The ADHD children had a higher CPT-Inattention score and showed smaller parietal positive waves at a latency of approximately 300 msec in reaction to target stimuli, target P3s, likewise indicating less attention. In contrast, they showed neither higher CPT-Impulsivity nor a smaller frontocentral negative wave at about 200 msec (N2); the N2 is generally seen as reflecting inhibition. A subgroup of children with ADHD and oppositional defiant disorder (n = 6) had smaller N2 waves than controls, however.


CONCLUSIONS
The ADHD group studied showed deficits in attention but not in impulsivity (or inhibition).
Overtoom
C C
CC
Faculty of Pharmacy, Department of Psychopharmacology, Utrecht, The Netherlands.
Verbaten
M N
MN
Kemner
C
C
Kenemans
J L
JL
van Engeland
H
H
Buitelaar
J K
JK
Camfferman
G
G
Koelega
H S
HS
D000293:Adolescent; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000503:physiopathology*; D007266:Inhibition, Psychological; D008297:Male; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D012044:Regression Analysis