Assessing the Relationship of Brain Metabolites to Cortical Thickness and Dementia Symptoms in Adults with Down Syndrome: A Pilot Study

Background/Objectives: Those with the genetic disorder Down syndrome are at high risk of developing Alzheimer's disease. Previous work shows group differences in magnetic resonance spectroscopy metabolite measures in adults with Down syndrome who have Alzheimer's disease-related dementia compared to those who do not. In this pilot study, we assess relationships between metabolites and measures related to dementia status in a sample of adults with Down syndrome. Methods: Seventeen adults with Down syndrome were scanned using a 3 tesla MRI scanner. Magnetic resonance spectroscopy scans focused on the hippocampus and dorsal lateral prefrontal cortex. Metabolites of interest, including myo-inositol and N-acetyl-aspartate, were correlated with scores on the Dementia Questionnaire for People with Learning Disabilities, cortical thickness, and a measure of cognitive ability. In addition, cortical thickness was compared to an age- and sex-matched cohort of 17 previously scanned adults without Down syndrome. Results: Metabolite measures were not significantly related to cognitive/behavioral measures or to cortical thickness in this small cohort. Participants with Down syndrome showed widespread increases in cortical thickness compared to controls, even after accounting for potential differences in grey matter/white matter contrast. Conclusions: Metabolite values were not related to two continuous measures that have previously been associated with dementia status in those with Down syndrome.