Proton MR spectroscopy: higher right anterior cingulate N-acetylaspartate/choline ratio in Asperger syndrome compared with healthy controls.

BACKGROUND AND PURPOSE One former study reported higher prefrontal N-acetylaspartate (NAA) levels in patients with Asperger syndrome (AS). The objective of the current study was to test the hypothesis that patients with AS would have higher dorsolateral prefrontal and anterior cingulate cortex NAA/creatine (Cr) and that NAA/Cr would be correlated with symptom severity. MATERIALS AND METHODS NAA/choline (Cho), NAA/Cr, and Cho/Cr values revealed by (1)H-MR spectroscopy in 14 right-handed male patients with AS (6 medicated with risperidone), 17-38 years of age, diagnosed by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria were compared with those of 21 right-handed male controls frequency-matched by age and intelligence quotient scores. RESULTS Patients with AS had significantly higher anterior cingulate NAA/Cho levels (z = -2.18, P = .028); there was a statistical trend for higher anterior cingulate NAA/Cr (z = -1.81, P = .069) that was significant when only the unmedicated patients with AS were taken into account (z = -1.95, P = .050). There were no significant differences in dorsolateral prefrontal MR spectroscopy values. CONCLUSIONS Our findings show that individuals with AS had higher NAA/Cho levels in the right anterior cingulate compared with healthy controls and that higher anterior cingulate NAA/Cho levels were correlated with higher Yale-Brown Obsessive Compulsive Scale total scores.