A Proton Magnetic Resonance Spectroscopy Study of Brain

Methods: We used in vivo proton magnetic resonance spectroscopy to examine neuronal integrity of the me- dial prefrontal and parietal lobes in 14 non-learning- disabled adults with AS and 18 control subjects (of simi- lar sex, age, and IQ). We obtained measures of the prefrontal lobe in 11, the parietal lobe in 13, and both lobes in 10 subjects with AS. We measured concentra- tions and ratios of N-acetylaspartate (NAA), creatine and phosphocreatine (Cr+PCr), and choline (Cho). Levels of NAA, Cr+PCr, and Cho are indicators of neuronal den- sity and mitochondrial metabolism, phosphate metabo- lism, and membrane turnover. Frontal metabolite levels were correlated with scores on the Yale-Brown Obses- sive Compulsive Scale and the Autism Diagnostic Inter- view. Results: Subjects with AS had a significantly higher pre- frontal lobe concentration of NAA (z= -3.1; P= .002), Cr+PCr (z=-2.2; P=.03), and Cho (z=-2.9; P=.003). In- creased prefrontal NAA concentration was significantly correlated with obsessional behavior (=0.67; P=.005); increased prefrontal concentration of Cho, with social function (=0.72; P=.02). We found no significant dif- ferences in parietal lobe metabolite concentrations. Conclusion: Subjects with AS have abnormalities in neu- ronal integrity of the prefrontal lobe, which is related to severity of clinical symptoms. Arch Gen Psychiatry. 2002;59:885-891