Journal of the International Neuropsychological Society



1H magnetic resonance spectroscopy, cognitive function, and apolipoprotein E genotype in normal aging, mild cognitive impairment and Alzheimer's disease


KEJAL  KANTARCI  a1, GLENN E.  SMITH  a2 a3 c1, ROBERT J.  IVNIK  a2 a3, RONALD C.  PETERSEN  a3 a4, BRADLEY F.  BOEVE  a3 a4, DAVID S.  KNOPMAN  a3 a4, ERIC G.  TANGALOS  a3 a5 and CLIFFORD R.  JACK  JR. a1 a3
a1 Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota
a2 Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota
a3 Alzheimer's Disease Research Center, Mayo Clinic, Rochester, Minnesota
a4 Department of Neurology, Mayo Clinic, Rochester, Minnesota
a5 Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota

Abstract

The aim of this study was to examine the associations of apolipoprotein E (APOE) genotype, metabolic changes in the posterior cingulate detected by 1H magnetic resonance spectroscopy (MRS), and neuropsychologic measures of memory and cognition both in normally aging elderly, and in patients with mild cognitive impairment (MCI) and AD. We studied 67 controls, 18 MCI and 33 AD patients. We used the Dementia Rating Scale total score (DRSTOT) as a measure of general cognitive function and the total learning from the Auditory Verbal Learning Test (AVTOT) as a measure of memory performance. No differences were noted on 1H-MRS metabolite ratios or cognitive measures across APOE genotype within control and patient groups. In controls, age was a significant predictor of both cognitive test scores, and NAA/Cr was a univariate associate of DRSTOT. All 3 1H-MRS metabolite ratios, N-acetylaspartate (NAA)/creatine (Cr), myoinositol (MI)/Cr, and NAA/MI, were univariate associates of AVTOT and DRSTOT scores in the combined MCI and AD group. In stepwise regression analyses in the combined patient group only NAA/MI entered the models. These data suggest NAA/Cr could be a modest predictor of general cognitive function in both healthy elderly and impaired patients, while MI/Cr is a more specific marker for neuropsychologic dysfunction associated with neurodegenerative disease. Among 1H-MRS measurements, the NAA/MI ratio maybe the most efficient predictor of memory and cognitive function in patients with MCI and AD. (JINS, 2002, 8, 934–942.)

(Received January 18 2002)
(Revised June 3 2002)
(Accepted June 7 2002)


Key Words: 1HMRS; Cognition; Aging; Mild cognitive impairment; Alzheimer's disease.

Correspondence:
c1 Reprint requests to: Glenn Smith, Ph.D., Department of Psychiatry and Psychology, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55901. E-mail: smith.glenn@mayo.edu.