[Attention deficit hyperactivity disorder. Cerebral asymmetry observed on magnetic resonance].
BACKGROUND
Anatomical and functional neuroimaging data from subjects with Attention Deficit Hyperactivity Disorder (ADHD) have consistently implicated a reversal of cerebral asymmetry and suggested a fronto-striatal dysfunction in this disorder.


OBJECTIVE
The aim of this study is to investigate the brain asymmetries in a homogeneous and non-medicated sample of adolescents with ADHD who had been previously studied in our laboratory.


METHODS
T1-weighted magnetic resonance images were obtained for 11 adolescents with ADHD and 19 control subjects. Frontal and posterior brain regions, caudate nucleus, and ventricular system were quantitatively measured.


RESULTS
A reversed pattern of asymmetry for the caudate nucleus (right > left) was found in ADHD when compared to the control group. We also found a reversed pattern of asymmetry for the frontal lobe (right < left) and a smaller right frontal volume (prefrontal specifically) in the ADHD subjects most severely impaired. Right caudate and frontal measures were inversely correlated.


CONCLUSIONS
ADHD is associated with fronto-striatal abnormalities, which may be explicable via extant neurodevelopmental theories. Enlargement of the right caudate nucleus may suggest the failure of a process of synaptic 'pruning' by which attentional functions could be improperly transferred from the basal ganglia to frontal regions during development.
Pueyo
R
R
Departamento de Psiquiatría y Psicobiología Clínica, Universitat de Barcelona, España.
Mañeru
C
C
Vendrell
P
P
Mataró
M
M
Estévez-González
A
A
García-Sánchez
C
C
Junqué
C
C
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000503:physiopathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D002421:Caudate Nucleus / Q000002:abnormalities; D003342:Corpus Striatum / Q000002:abnormalities / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000002:abnormalities / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011569:Psychiatric Status Rating Scales; D014888:Wechsler Scales