Proton MR Spectroscopy Correlates of Frontal Lobe Function in Healthy Children

BACKGROUND AND PURPOSE: Neuroimaging methods have been used to improve our understanding of the topographic organization of the brain. In our study, proton H-1-MR spectroscopic imaging was used to evaluate frontal lobe function. The goal was to determine the relationship between neuropsychological measures of frontal lobe function and levels of a surrogate neuronal marker, N-acetylaspartate (NAA), in typically developing healthy children and adolescents. MATERIALS AND METHODS: Fifty-one healthy children (25 girls; 6.2-18.3 years of age; mean age, 12.3 +/- 3.6 years) were examined. All children completed a neuropsychological assessment including measures of attention, executive function, memory, language, and visual and motor skills. H-1-MR spectroscopic imaging was performed by using a multisection spin-echo sequence at 1.5T. General linear model analysis of covariance was used to examine the relationship between the neuropsychological test scores and NAA/creatine (Cr) ratios, controlling for age and sex. RESULTS: A positive relationship between frontal lobe white matter NAA/Cr ratio and performance on 2 neuropsychological tests associated with frontal lobe function was detected. The Purdue Pegboard right-hand scores were higher with increasing NAA/Cr in the left frontal white matter (P = .047), and Stanford-Binet-IV "Bead Memory" scores improved with increasing NAA/Cr ratio in the right frontal white matter (P = .032). CONCLUSIONS: An association between frontal white matter NAA/Cr ratios and 1) measures of manual speed and dexterity, and 2) visual working memory was detected. Our data may provide a quantitative basis for assessment of frontal lobe impairments in disease states.