Attention Deficit Hyperactivity Disorder

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Attention Deficit Hyperactivity Disorder
T. FISHER , H. PRATT and J. AHARON
Evoked Potentials Laboratory Technion-Israel
Institute of Technology, Haifa, Israel
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The three main symptoms of ADHD
Inattention
Impulsivity
Hyperactivity
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What are the brain processes associated with the
behavioral impulsivity symptoms?
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Subjects

• 14 subjects diagnosed with Attention Deficit and
  Hyperactivity disorder.
• 14 healthy control subjects matched for age and
  gender
• Age range 18-30. No co-morbidity of psychiatric,
  neurological or learning disabilities.
• All subjects were free of medication.

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Procedure

• Stimuli 2 binaural tones 1000 Hz (NO-GO)
  2000 Hz (GO) 60 dBnHL for 40 ms.
• Inter-trial interval 1000 to 2000 ms
• Task To GO trials press button to stimuli.
  Probability 80.
• To NO-GO trials inhibit the response.
  Probability 20.

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GO NO-GO Behavioral Results
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Electrophysiological resultsgrand average, 28
subjects, midline electrodes
Control subjects
ADHD subjects
P3
P3
N2
N2
P3
P3
N2
N2
P3
P3
N2
N2
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ADHD vs. CTRL in NO-GO Trials
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LORETA images of Control ADHD difference
No go , significant voxels, Plt0.05
187- 207 msec
R. Inf. frontal gyrus BA 9, 44,45
Control gt ADHD
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LORETA images of significant T values
No go , significant voxels, Plt0.05
308-339 Msec
Posterior Cingulate BA 23,29,30,31
Control gt ADHD
stimulus
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Conclusions

• The ADHD deficit is in stimulus-related
  processing, not at the perceptual level.
• ADHD show abnormal activity in brain regions
  attributed to response inhibition and conflict
  monitoring.

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CTRL N2
N2
ADHD N2
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CTRL P3
ADHD P3
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