Objective : The purpose of this study was to examine the regional cerebral blood-flow(rCBF) difference between boys with pure ADHD and normal controls before and after methylphenidate treatment, and also we examined the association between rCBF changes and cognitive characteristics of boys with pure ADHD before and after methylphenidate treatment.
Methods : The rCBF of 5 boys with pure ADHD and 5 control boys were examined by Tc-99m ECD brain SPECT and cognitive characteristics by ADS and every 5 ADHD boys took MPH for 12 to 16 weeks. After that all ADHD boys took Tc-99m ECD brain SPECT and checked ADS again. rCBF difference and changes before and after MPH treatment were quantified and analyzed by Using SPM. And, associations between types of cognitive changes measured by ADS and rCBF changes were examined, and quantitative associations between them were also analyzed by using Pearson´s coefficient correlation.
Results : 1) Before MPH treatment, rCBF of ADHD boys were significantly decreased in left orbitofrontal area and left caudate nucleus compared to normal controls. 2) After MPH treatment, rCBF of the same regions were significantly increased. 3) There was positive correlation between the degree of commission error(impulsivity, disinhibition) among tf-=: -- ; ~ variables and the degree of blood--flow decrease in above two areas before MPH treatment but after MPH -.; ~ment, only with the degree of rCBF increase in Lt orbitofrontal area.
Conclusion These r; suggest that the pathophysiology of impulsivity or disinhibition of the characteristic symptoms of ADHD bc~~, ; assocated with hypoactivities of left orbitofrontal area and left caudate nucleus, and MPH pharmacodynamic ~, r ADHD boys is associated to their acticns on these two areas.
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