Higher Glutamate plus Glutamine and Reduction of N-acetylaspartate in Posterior Cingulate According to Age Range in Patients with Cognitive Impairment and/or Pain

Rationale and Objectives: The aim of the study was to analyze 1) whether the metabolite levels in the posterior cingulate cortex (PCC) are different in healthy individuals compared to a group of patients with cognitive impairment and/or pain and 2) whether there exists a correlation between brain metabolites and the age of a patient. Materials and Methods: Two hundred seven patients with cognitive impairment and/or pain (66 mild cognitive impairment, 54 fibromyalgia, 36 Alzheimer disease, 33 interictal migraine, 10 somatization disorder, and 8 after trigeminal neuralgia, and 193 healthy participants adjusted for gender and age. Proton magnetic resonance spectroscopy (MRS) of the brain was performed with the voxel placed in the ventral PCC and postprocessed with LCModel (Stephen Provencher, Oakville, Ontario, Canada). Results: Using linear regression and adjusting for gender and age, mean brain metabolite values for the pathological group, when compared-to healthy controls, were significantly lower in N-acetylaspartate (P = .003) and N-acetylaspartate/creatine (P = .015) and significantly greater in glutamate + glutamine (P < .001) and glutamate + glutamine/creatine (P < .000). All metabolites were significantly correlated with age: glutamate, glutamate + glutamine, N-acetylaspartate, and their creatine ratios exhibited a negative correlation, whereas myoinositol and choline exhibited a positive correlation. Conclusions: Although the number of patients is relatively small with heterogeneous state of disease, MRS in PCC may serve as a useful noninvasive tool for diagnostic of patients with cognitive impairment and pain.