TY - JOUR
T1 - fMRI of intrasubject variability in ADHD
T2 - Anomalous premotor activity with prefrontal compensation
AU - Suskauer, Stacy J.
AU - Simmonds, Daniel J.
AU - Caffo, Brian S.
AU - Denckla, Martha B.
AU - Pekar, James J.
AU - Mostofsky, Stewart H.
N1 - Funding Information:
This study was supported by the National Institute of Neurological Disorders and Stroke: K02NS04485 (S.M.), R01NS047781 (S.M.); the National Institute of Child Health and Human Development: K12HD001097 (S.S.), P30HD24061 (Mental Retardation and Developmental Disabilities Research Center); and Johns Hopkins General Clinical Research Center M01RR00052.
PY - 2008/10
Y1 - 2008/10
N2 - Objective: Children with attention-deficit/hyperactivity disorder (ADHD) consistently display increased intrasubject variability (ISV) in response time across varying tasks, signifying inefficiency of response preparation compared to typically developing (TD) children. Children with ADHD also demonstrate impaired response inhibition; inhibitory deficits correlate with ISV, suggesting that similar brain circuits may underlie both processes. To better understand the neural mechanisms underlying increased ISV and inhibitory deficits in children with ADHD, functional magnetic resonance imaging was used to examine the neural correlates of ISV during Go/No-go task performance. Method: Event-related functional magnetic resonance imaging was used to study 25 children with ADHD and 25 TD children ages 8 to 13 years performing a simplified Go/No-go task. Brain-behavior correlations were examined between functional magnetic resonance imaging activation and ISV within and between groups. Results: For TD children, increased rostral supplementary motor area (pre-supplementary motor area) activation during No-go events was associated with less ISV, whereas the reverse was true for children with ADHD for whom increased pre-supplementary motor area activation was associated with more ISV. In contrast, children with ADHD with less ISV showed greater prefrontal activation, whereas TD children with more prefrontal activation demonstrated more ISV. Conclusions: These findings add to evidence that dysfunction of premotor systems may contribute to increased variability and impaired response inhibition in children with ADHD and that compensatory strategies eliciting increased cognitive control may improve function. However, recruitment of prefrontal resources as a compensatory mechanism for motor task performance may preclude the use of those prefrontal resources for higher order, more novel executive functions with which children with ADHD often struggle.
AB - Objective: Children with attention-deficit/hyperactivity disorder (ADHD) consistently display increased intrasubject variability (ISV) in response time across varying tasks, signifying inefficiency of response preparation compared to typically developing (TD) children. Children with ADHD also demonstrate impaired response inhibition; inhibitory deficits correlate with ISV, suggesting that similar brain circuits may underlie both processes. To better understand the neural mechanisms underlying increased ISV and inhibitory deficits in children with ADHD, functional magnetic resonance imaging was used to examine the neural correlates of ISV during Go/No-go task performance. Method: Event-related functional magnetic resonance imaging was used to study 25 children with ADHD and 25 TD children ages 8 to 13 years performing a simplified Go/No-go task. Brain-behavior correlations were examined between functional magnetic resonance imaging activation and ISV within and between groups. Results: For TD children, increased rostral supplementary motor area (pre-supplementary motor area) activation during No-go events was associated with less ISV, whereas the reverse was true for children with ADHD for whom increased pre-supplementary motor area activation was associated with more ISV. In contrast, children with ADHD with less ISV showed greater prefrontal activation, whereas TD children with more prefrontal activation demonstrated more ISV. Conclusions: These findings add to evidence that dysfunction of premotor systems may contribute to increased variability and impaired response inhibition in children with ADHD and that compensatory strategies eliciting increased cognitive control may improve function. However, recruitment of prefrontal resources as a compensatory mechanism for motor task performance may preclude the use of those prefrontal resources for higher order, more novel executive functions with which children with ADHD often struggle.
KW - Attention-deficit/hyperactivity disorder
KW - Intrasubject variability
KW - Response inhibition
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U2 - 10.1097/CHI.0b013e3181825b1f
DO - 10.1097/CHI.0b013e3181825b1f
M3 - Article
C2 - 18724253
AN - SCOPUS:55249105242
SN - 0890-8567
VL - 47
SP - 1141
EP - 1150
JO - Journal of the American Academy of Child and Adolescent Psychiatry
JF - Journal of the American Academy of Child and Adolescent Psychiatry
IS - 10
ER -