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This Article Figures Only Full Text Full Text (PDF) Take the CME quiz CME: Take the course for this article: Volume 70, Number 18, April 29, 2008 All Versions of this Article: 01.wnl.0000306314.77311.bev1 70/18/1594    most recent Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Zimmerman, M. E. Articles by Lipton, R. B. PubMed PubMed Citation Articles by Zimmerman, M. E. Articles by Lipton, R. B. Related Collections MRS Volumetric MRI Memory Cognitive aging

Hippocampal neurochemistry, neuromorphometry, and verbal memory in nondemented older adults

From the Saul R. Korey Department of Neurology (M.E.Z., M.J.K., J.V., H.B., C.A.D., R.B.L.), Albert Einstein College of Medicine, Bronx, NY; and Department of Neurosurgery (J.W.P., H.P.H.), Yale University School of Medicine, New Haven, CT.

Address correspondence and reprint requests to Dr. Molly E. Zimmerman, Albert Einstein College of Medicine, Saul R. Korey Department of Neurology, 1165 Morris Park Ave., Room 343, Bronx, NY 10461 mzimmerm{at}aecom.yu.edu

Background: Characterization of the behavioral correlates of neuromorphometry and neurochemistry in older adults has important implications for an improved understanding of the aging process. The objective of this study was to test the hypothesis that a measure of hippocampal neuronal metabolism was associated with verbal memory in nondemented older adults after controlling for hippocampal volume.

Methods: 4-T MRI, proton magnetic resonance spectroscopy (¹H MRS), and neuropsychological assessment were conducted in 48 older adults (23 women; mean age 81 years). Average hippocampal N-acetyl aspartate/creatine ratios (NAA/Cr) and hippocampal volumes were obtained. Neuropsychological evaluation included tests of verbal memory (Buschke and Grober Free and Cued Selective Reminding Test–Immediate Recall [FCSRT-IR], Wechsler Memory Scale–Revised Logical Memory subtest) and attention and executive function (Trail Making Test Parts A and B).

Results: Linear regression analysis indicated that after adjusting for age, hippocampal NAA/Cr was a significant predictor of FCSRT-IR performance (β = 0.38, p = 0.01, R ² = 0.21). Hippocampal volume was also a significant predictor of FCSRT-IR performance after adjusting for age and midsagittal area (β = 0.47, p = 0.01, R ² = 0.24). In a combined model, hippocampal NAA/Cr (β = 0.33, p = 0.03) and volume (β = 0.35, p = 0.03) were independent predictors of FCSRT-IR performance, accounting for 30% of the variance in memory.

Conclusions: These findings indicate that nondemented older adults with smaller hippocampal volumes and lower levels of hippocampal N-acetyl aspartate/creatine ratio metabolites perform more poorly on a test of verbal memory. The integrity of both the structure and metabolism of the hippocampus may underlie verbal memory function in nondemented elderly.

GLOSSARY: BIMC = Blessed Information-Memory-Concentration test; CDR = Clinical Dementia Rating scale; EAS = Einstein Aging Study; FCSRT-IR = Buschke and Grober Free and Cued Selective Reminding Test–Immediate Recall; FOV = field of view; LM = Wechsler Memory Scale–Revised Logical Memory subtest; MCI = mild cognitive impairment; MR = magnetic resonance; MRS = magnetic resonance spectroscopy; NAA/Cr = N-acetyl aspartate/creatine ratio; TMTA = Trail Making Test Part A; TMTB = Trail Making Test Part B.

Supported by National Institute on Aging Grant AG03949.

e-Pub ahead of print on March 26, 2008, at www.neurology.org.

Disclosure: The authors report no conflicts of interest.

Received September 10, 2007. Accepted in final form December 14, 2007.