A Comprehensive Review of Proton Magnetic Resonance Spectroscopy Studies in Dementia and Parkinson's Disease

We reviewed the literature of proton magnetic resonance spectroscopy (MRS) in dementia and Parkinson's disease (PD) and quantitatively compared the reported values of the markers N-acetyl aspartate (NAA), choline, and myo-Inositol between control and disease groups. We analysed a total of 27 reports in dementia. Combining the quantitative data from these showed a relative decrease of 15% in NAA level in the temporal lobe tissue in patients with Alzheimer's disease (AD) compared with controls. The rest of the brain showed a seemingly uniform 10% decrease in NAA levels in AD compared with controls. myo-Inositol was raised by about 15%, again uniformly throughout the brain, but there was no evidence for changed levels of choline. We found 15 reports of MRS in PD, which show a small decrease (5%) in the NAA level in the lentiform nucleus compared with controls. In progressive supranuclear palsy (PSP), there is a greater decrease in NAA levels in the frontal region and the lentiform nucleus. This may aid in the diagnosis of PSP. Further research is needed to determine spectroscopic changes in other dementias, to monitor how markers change with disease progression and to establish clinical utility.