In vivo neurochemical characteristics of normal and pathological aging of the brain: Role of magnetic resonance spectroscopy

Summary he aim of better understanding the possibility of differentiating in vivo normal aging brain from pathological conditions, we carried out proton magnetic resonance spectroscopy (1H-MRS) in patients suffering from Alzheimer disease (AD) and age-matched controls. 1H-MRS was performed in temporal gray matter and in frontal white matter. A significant decrease of N-acetyl-aspartate (NAA) in both gray and white matters, and an increase of myo-inositol (MI) in gray matter of AD patients were observed. Gray matter NAA/MI ratio clearly separated the two groups. White matter MI was significantly associated with severity and duration of dementia, while no association with age was documented. Cluster analysis showed that MI is an early indicator of the disease, while NAA decreases along with progression of dementia. It is concluded that 1H-MRS can help in differentiating normal aging from AD and can be of help in defining in vivo the molecular characteristics of different AD stages.