Proton magnetic resonance spectroscopy investigation of the right frontal lobe in children with attention-deficit/hyperactivity disorder

Objective: To investigate neurometabolite concentrations in right prefrontal white matter in children with attention-deficit/hyperactivity disorder (ADHD) and relations of neurometabolites with attention skill and frontal anatomy. Method: Single voxel proton magnetic resonance spectroscopy (H-1-MRS), quantitative morphometric analysis of left and right dorsolateral frontal volumes, and assessment of attentional problems with the Conners Continuous Performance Test were undertaken in 23 children (17 male) with ADHD (with no comorbid learning disabilities) and 24 matched controls (16 male). Results: No overall group differences were found for any neurometabolite. However, a group by sex interaction was noted for N-acetylaspartate, such that girls with ADHD had especially low concentrations. Morphological analyses revealed smaller right (but not left) dorsolateral volumes in children with ADHD, and in the ADHD group this volume correlated with neurometabolite concentrations. In the ADHD group Continuous Performance Test performance was related to both dorsolateral volume and the creatine-phosphocreatine peak from H-1-MRS. Conclusions: These results add to a growing body of evidence suggesting sex-specific neurobiological differences in ADHD and draw attention to relationships between neurochemistry, neuroanatomy, and performance in children with ADHD. Study limitations include small sample size and clinical heterogeneity among the children with ADHD.