title: Magnetic resonance spectroscopy, β-amyloid load, and cognition in a population-based sample of cognitively normal older adults.
abstract: OBJECTIVE
  To determine the relationship between proton magnetic resonance spectroscopy ((1)H MRS) metabolites and β-amyloid (Aβ) load and the effects of Aβ load on the association between (1)H MRS metabolites and cognitive function in cognitively normal older adults.
  
  
  METHODS
  We studied 311 cognitively normal older adults who participated in the population-based Mayo Clinic Study of Aging from January 2009 through September 2010. Participants underwent (11)C-Pittsburgh compound B (PiB) PET, (1)H MRS from the posterior cingulate gyri, and neuropsychometric testing to assess memory, attention/executive, language, and visual-spatial domain functions within 6 months. Partial Spearman rank order correlations were adjusted for age, sex, and education.
  
  
  RESULTS
  Higher PiB retention was associated with abnormal elevations in myoinositol (mI)/creatine (Cr) (partial r(s) = 0.17; p = 0.003) and choline (Cho)/Cr (partial r(s) = 0.13; p = 0.022) ratios. Higher Cho/Cr was associated with worse performance on Auditory Verbal Learning Test Delayed Recall (partial r(s) = -0.12; p = 0.04), Trail Making Test Part B (partial r(s) = 0.12; p = 0.04), Wechsler Adult Intelligence Scale-Revised (WAIS-R) Digit Symbol (partial r(s) = -0.18; p < 0.01), and WAIS-R Block Design (partial r(s) = -0.12; p = 0.03). Associations between (1)H MRS metabolites and cognitive function were not different among participants with high vs low PiB retention.
  
  
  CONCLUSIONS
  In cognitively normal older adults, the (1)H MRS metabolite ratios mI/Cr and Cho/Cr are associated with the preclinical pathologic processes in the Alzheimer disease cascade. Higher Cho/Cr is associated with worse performance on domain-specific cognitive tests independent of Aβ load, suggesting that Cho/Cr elevation may also be dependent on other preclinical dementia pathologies characterized by Cho/Cr elevation such as Lewy body or ischemic vascular disease in addition to Aβ load.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA. kantarci.kejal@mayo.edu
authors.forename: Kejal
authors.initials: K
authors.lastname: Kantarci
authors.forename: V
authors.initials: V
authors.lastname: Lowe
authors.forename: S A
authors.initials: SA
authors.lastname: Przybelski
authors.forename: M L
authors.initials: ML
authors.lastname: Senjem
authors.forename: S D
authors.initials: SD
authors.lastname: Weigand
authors.forename: R J
authors.initials: RJ
authors.lastname: Ivnik
authors.forename: R
authors.initials: R
authors.lastname: Roberts
authors.forename: Y E
authors.initials: YE
authors.lastname: Geda
authors.forename: B F
authors.initials: BF
authors.lastname: Boeve
authors.forename: D S
authors.initials: DS
authors.lastname: Knopman
authors.forename: R C
authors.initials: RC
authors.lastname: Petersen
authors.forename: C R
authors.initials: CR
authors.lastname: Jack
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016229:Amyloid beta-Peptides / Q000009:adverse effects / Q000378:metabolism*; D002794:Choline / Q000096:biosynthesis / Q000378:metabolism; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000378:metabolism / Q000523:psychology; D003404:Creatinine / Q000378:metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests; D011159:Population Surveillance / Q000379:methods; D011446:Prospective Studies; D055550:Protein Stability
chemical_list: D016229:Amyloid beta-Peptides; D003404:Creatinine; D002794:Choline