IN-VIVO NEUROCHEMICAL CHARACTERISTICS OF NORMAL AND PATHOLOGICAL AGING OF THE BRAIN - ROLE OF MAGNETIC-RESONANCE SPECTROSCOPY

With the aim of better understanding the possibility of differentiatin g in vivo normal aging brain from pathological conditions, we carried out proton magnetic resonance spectroscopy (H-1-MRS)(1) in patients su ffering from Alzheimer disease (AD) and age-matched controls. H-MRS wa s performed in temporal gray matter and in frontal white matter. A sig nificant decrease of N-acetyl-aspartate (NAA) in both gray and white m atters, and an increase of myo-inositol (MI) in gray matter of AD pati ents were observed. Gray matter NAA/MI ratio clearly separated the two groups. White matter MI was significantly associated with severity an d duration of dementia, while no association with age was documented. Cluster analysis showed that Mi is an early indicator of the disease w hile NAA decreases along with progression of dementia. it is concluded that 1 H-MRS can help in differentiating normal aging from AD and can be of help in defining in vivo the molecular characteristics of diffe rent AD stages.