Volumetric MRI analysis comparing subjects having attention-deficit hyperactivity disorder with normal controls

Area of Science:

• Neuroimaging and Developmental Neuroscience
• Brain Morphology and Function
• Pediatric Neurology

Background:

• Attention-deficit hyperactivity disorder (ADHD) is a complex neurodevelopmental disorder with suspected underlying structural brain abnormalities.
• Previous research suggests potential alterations in specific brain regions, but localized evidence has been limited.

Purpose of the Study:

• To investigate localized developmental anomalies in brain structure in individuals with ADHD using MRI-based morphometry.
• To test hypotheses regarding structural differences in the left caudate and right prefrontal/frontal/parietal regions.

Main Methods:

• A case-control study involving 15 male subjects with ADHD and 15 age- and IQ-matched male controls.
• MRI-based morphometry was used to measure global and regional brain volumes, including cerebral hemispheres, cortex, white matter, and subcortical nuclei.
• Group-matched for age, IQ, and handedness.

Main Results:

• Subjects with ADHD exhibited smaller volumes in the left caudate nucleus and reversed caudate asymmetry.
• Reduced volumes were also observed in the right anterior-superior (frontal) region and bilateral anterior-inferior regions.
• Smaller white matter volumes were found in the right anterior-superior and bilateral retrocallosal (parietal-occipital) regions in the ADHD group.

Conclusions:

• This study provides the first evidence of localized hemispheric structural anomalies in ADHD.
• The findings align with theoretical models implicating frontal-striatal and parietal network dysfunction in ADHD.
• Structural differences may underlie varying responses to stimulant medications in individuals with ADHD.