Cerebellar neurometabolite abnormalities in pediatric attention/deficit hyperactivity disorder: a proton MR spectroscopic study.

We designed a case-control proton magnetic resonance spectroscopic study comparing the cerebellar and prefrontal regions of a group of 17 ADHD (attention deficit/hyperactivity disorder) medicated children and a group of 17 control children matched for laterality, gender and age. As we had found decreased gray matter volume in the right prefrontal region and the left cerebellar hemisphere in a previous voxel-based morphometry study conducted on an independent ADHD sample, we tested the hypothesis that these regions should show neurometabolite abnormalities. MRI (magnetic resonance imaging) was performed with a 1.5 T system; spectral acquisition was performed with a single-voxel technique and a PRESS sequence. Two volumes of interest were selected in the right prefrontal region and the left cerebellar hemisphere. NAA (N-acetylaspartate), Cre (creatine), Cho (choline), MI (myo-inositol) and Glx (glutamate-glutamine) resonance intensities were absolutely quantified. In the left cerebellar hemisphere, ADHD children showed significant decreased MI and NAA absolute concentrations with high effect sizes (p=0.004, ES=1.184; p=0.001, ES=1.083). The diminished absolute concentration of the NAA could be related to a gray matter volume decrease in the same cerebellar region found in the previous voxel-based morphometry MRI study, while the reduced MI absolute concentration could express a decreased glial density. This is the first proton MR spectroscopic study examining the cerebellum and it provides additional support for the role of cerebellum in the ADHD neurobiology. (c) 2009 Elsevier Ireland Ltd. All rights reserved.