High brain myo-inositol levels in the predementia phase of Alzheimer's disease in adults with Down's syndrome : A 1H MRS study

OBJECTIVE: An extra portion of chromosome 21 in Down’s syndrome leads to a dementia in later life that is phenotypically similar to Alzheimer’s disease. Down’s syndrome therefore represents a model for studying preclinical stages of Alzheimer’s disease. Markers that have been investigated in symptomatic Alzheimer’s disease are myo-inositol and N-acetylaspartate. The authors investigated whether abnormal brain levels of myo-inositol and other metabolites occur in the preclinical stages of Alzheimer’s disease associated with Down’s syndrome. METHOD: The authors used 1H magnetic resonance spectroscopy (MRS) with external standards to measure absolute brain metabolite concentrations in 19 nondemented adults with Down’s syndrome and 17 age- and sex-matched healthy comparison subjects. RESULTS: Concentrations of myo-inositol and choline-containing compounds were significantly higher in the occipital and parietal regions of the adults with Down’s syndrome than in the comparison subjects. Within the Down’s syndro...