attention deficit hyperactivity disorder

ATTENTION DEFICIT ATTENTION DEFICIT HYPERACTIVITY HYPERACTIVITY

DISORDERDISORDER

Further explained Further explained

ComorbiditiesComorbidities

CDCD ODDODD

MMR LD ADHD PDD-NOS HFAMMR LD ADHD PDD-NOS HFA

PKU PKU CHTCHT

Developmental pathwayDevelopmental pathway

depression/anxiety depression/anxiety

Childhood Adulthood ADHDChildhood Adulthood ADHD impulsivityimpulsivity CD CD

Core symptoms persistCore symptoms persist MPH treatmentMPH treatment

DIAGNOSTIC MEASURESDIAGNOSTIC MEASURES

QuestionnairesQuestionnaires (Semi) Structured Interviews(Semi) Structured Interviews DIAGNOSIS BY HEARSAYDIAGNOSIS BY HEARSAY PARENT + TEACHERPARENT + TEACHER Third observational condition??Third observational condition??

Important cognitive theoriesImportant cognitive theories

response inhibition hypothesisresponse inhibition hypothesis Barkley (1997) Barkley (1997) Psychological Bulletin, 121Psychological Bulletin, 121,, 65-9465-94 (frontal) paper and pencil tests(frontal) paper and pencil tests delayed responding testsdelayed responding tests stop taskstop task

Delayed response testDelayed response testProfile control childProfile control child

trial time in seconds after stimulustrial time in seconds after stimulus

1 2 3 4 5 6 7 81 2 3 4 5 6 7 8 1 x 1 x 2 x2 x 3 x3 x 4 x4 x 5 x5 x 6 x6 x 7 x7 x

Profile child with ADHDProfile child with ADHD

trial time in seconds after stimulustrial time in seconds after stimulus 1 2 3 4 5 6 7 81 2 3 4 5 6 7 8 1 x 1 x 2 x2 x 3 x3 x 4 x4 x 5 x5 x 6 x6 x 7 x7 x

Delay Aversion TheoryDelay Aversion Theory

Sonuga Barke et al. (1992) - Sonuga Barke et al. (1992) - Journal of Child Journal of Child

Psychology and Psychiatry, 33Psychology and Psychiatry, 33, 387-398, 387-398

Sonuga Barke (2002) - Sonuga Barke (2002) - Behavioural Brain Behavioural Brain Research, 130Research, 130, 29-36, 29-36

extra effort

no extra effort

optimal state non-optimal state

Perf

orm

an

ce

Actual state vs. required (target) state – effort allocationActual state vs. required (target) state – effort allocation

Theory of state regulationTheory of state regulation

Signal rate Signal rate

05101520253035404550

fast slow

ADHDControlsothers

extra effort

no extra effort

optimal state non-optimal state

Perf

orm

an

ce

Actual state vs. required (target) state – effort allocationActual state vs. required (target) state – effort allocation

Theory of state regulationTheory of state regulation

Physiological costs

Heart rate variability

P300 amplitude

fMRI

NRT is a neural sheet draped over the lateral/anterior aspects of the thalamus

NRT is the functional interface between the arousal and attention systems

Receives axonal collaterals from corticothalamic, thalamocortical and reticular formation projections

Nucleus Reticularis Thalami

Portas et al. 1998, J. of Neuroscience, 18

Go No-Go testGo No-Go test

7,2

7,4

7,6

7,8

8

8,2

Mo

d.

Ind

ex (

ln)

Fast Slow

test condition

Heart rate variability (0.10 Hz )

ADHD

Controls

ERPsERPs Tracking of covert information processingTracking of covert information processing Excellent temporal resolution Excellent temporal resolution More direct assessment of energetic More direct assessment of energetic

mechanismsmechanisms