MR spectroscopy of cerebral white matter in type 2 diabetes; no association with clinical variables and cognitive performance

Type 2 diabetes (DM2) is associated with cognitive decline, but the pathogenesis of this important complication remains unclear. We investigated whether abnormalities in neuronal metabolism or membrane integrity in normal appearing cerebral white matter are associated with cognitive impairment in patients with DM2. Single voxel proton magnetic resonance spectroscopy (1.5 T), aimed at N-acetyl-aspartate (NAA), total choline (Cho), and total creatine (Cr), was performed in the cerebral white matter (centrum semiovale) of 72 patients with DM2 and 40 control subjects. All participants underwent extensive neuropsychological evaluation. Patients with DM2 performed worse with respect to global neuropsychological functioning than controls (p < 0.05), in particular on memory and information processing speed. We observed no differences in NAA/Cr, Cho/Cr, or NAA/Cho ratio's between patients with DM2 and controls. Cognitive performance in patients with DM2 was not correlated with any of these brain metabolites, neither were the clinical variables. We conclude that disturbances in neuronal viability and cellular membrane status assessed by NAA/Cr, Cho/Cr, NAA/Cho ratios cannot explain cognitive decline in patients with DM2.