1H magnetic resonance spectroscopy, cognitive function, and apolipoprotein E genotype in normal aging, mild cognitive impairment and Alzheimer's disease

The aim of this study was to examine the associations of apolipoprotein E (APOE) genotype. metabolic changes in the posterior cingulate detected by H-1 magnetic resonance spectroscopy ( MRS), and neuropsychologic measures of memory and cognition both in normally aging elderly. and in patients with mild cognitive impairment ( MCI) and AD. We studied 67 controls. 18 MCI and 33 AD patients, We used the Dementia Rating Scale total score (DRSTOT) as a measure of general cognitive function and the total learning from the Auditor, Verbal Learning Test (AVTOT) as a measure of memory performance. No differences were noted on H-1-MRS metabolite ratios or cognitive measures across APOE genotype within control and patient groups. In controls. age was a significant predictor of both cognitive test scores, and NAA/Cr was a univariate associate of DRSTOT. All 3 H-1-MRS metabolite ratios. N-acetylaspartate (NAA)/creatine (Cr). myoinositol (MI)/Cr. and NAA/Ml, were univariate associates of AVTOT and DRSTOT scores in the combined MCI and AD group. In stepwise regression analyses in the combined patient group only NAA/MI entered the models. These data suggest NAA/Cr could be a modest predictor of general cognitive function in both healthy elderly and impaired patients, while MI/Cr is a more specific marker for neuropsychologic dysfunction associated with neurodegenerative disease. Among H-1-MRS measurements, the NAA/MI ratio maybe the most efficient predictor of memory and cognitive function in patients with MCI and AD.