Evidence of neurodegeneration in brains of older adults who do not yet fulfill MCI criteria
Received 12 November 2007; received in revised form 25 April 2008; accepted 1 May 2008. published online 13 June 2008.
Abstract
We sought to determine whether there are structural and metabolic changes in the brains of older adults with cognitive complaints yet who do not meet MCI criteria (i.e., preMCI). We compared the volumes of regional lobar gray matter (GM) and medial temporal lobe structures, including the hippocampus, entorhinal cortex (ERC), fusiform and parahippocampal gyri, and metabolite ratios from the posterior cingulate in individuals who had a Clinical Demetia Rating (CDR) of 0.5, but who did not meet MCI criteria (preMCI, N=17), patients with mild cognitive impairment (MCI, N=13), and cognitively normal controls (N=18). Controls had more ERC, fusiform, and frontal gray matter volume than preMCI and MCI subjects and greater parahippocampal volume and more posterior cingulate N-acetylaspartate (NAA)/myoinosotil (mI) than MCI. There were no significant differences between MCI and preMCI subjects on any of these measures. These findings suggest there are neurodegenerative changes in the brains of older adults who have cognitive complaints severe enough to qualify for CDR=0.5 yet show no deficits on formal neuropsychological testing. The results further support the hypothesis that detection of individuals with very mild forms of Alzheimer's disease (AD) may be facilitated by use of the CDR, which emphasizes changes in cognition over time within individuals rather than comparison with group norms.
aCenter for Imaging of Neurodegenerative Diseases, San Francisco VA Medical Center, San Francisco, CA 94121, USA
bDepartment of Radiology, University of California, San Francisco, San Francisco, CA 94143, USA
cDepartment of Psychiatry, University of California, San Francisco, San Francisco, CA 94143, USA
dDepartment of Neurology, University of California, San Francisco, San Francisco, CA 94143, USA
eCalifornia Pacific Medical Center, San Francisco, CA 94120-7999, USA
fDepartment of Neurology, University of California, Davis, CA 95817, USA
Corresponding author at: 4150 Clement Street, 114M, San Francisco VA Medical Center, San Francisco, CA 94121, USA. Tel.: +1 415 221 4810x4386; fax: +1 415 668 2864.
ABSTRACT