Alzheimer's disease (AD) most severely affects the fastest growing segment of our population: those age 80 and older. The ability to identify nondemented persons in a preclinical phase of AD will have far-reaching implications for both improved early diagnosis and use of anti-dementia pharmacologic therapies. Neuroprotective treatments will be most effective if applied at the earliest stages, which provides an important rationale for accurate preclinical detection. However, one of the remaining obstacles centers on the difficulty in identifying persons with AD before their deficits become clinically significant. Given the extent to which cognitive and brain changes associated with normal aging overlap with those of AD, the accurate detection of early AD in advanced age groups poses a number of unique challenges. We propose to conduct a five-year longitudinal study of the Very-Old (ages 80 and older) in which the combination of neuropsychological, neuroimaging, and genetic assessments will be examined, relative to the Young-Old (ages 60-79), in an effort to identify the most salient preclinical markers of AD. Our work during the previous project period has revealed important differences by age and genetic risk in the expression of cognitive and brain changes in clinical and preclinical AD. However, much remains to be done in characterizing the progression to AD in the Very-Old. Further clarification of the evolution of these brain and behavioral differences through the use of emerging neuropsychological (e.g., cognitive discrepancy measures) and functional magnetic resonance imaging (FMRI) techniques (e.g., combined arterial spin labeling/blood oxygen level dependent [ASL/BOLD] imaging) will advance our ability to understand the unique features associated with the development of AD in those at risk. Critical examination of another risk factor for AD conversion, mild cognitive impairment (MCI), will also represent a new aim for this project. Thus, the specific aims for this renewal period are (a) to determine the profile of spared and impaired cognitive processes associated with the preclinical phase of AD in the Very-Old, (b) to determine the clinical validity of a novel definitional scheme for MCI, its clinical outcomes, and whether differential rates of MCI and its various subtypes exist between Young-Old and Very-Old, (c) to use combined ASL/BOLD FMRI to measure functional changes within the medial temporal lobe (MTL) and related structures (e.g., parahippocampal gyrus, posterior cingulate) for the quantitative estimation of the cerebral metabolic rate of oxygen consumption (CMRO2) during episodic memory encoding, and (d) to integrate neuropsychological and neuroimaging methods to better determine the profile and progression of brain and behavioral changes indicative of the preclinical period of AD between the Young-Old and Very-Old. Public health relevance: Despite the many advances in neuropsychological and neuroimaging methods over the past decade, an effort focused on integrating these findings for prediction of progression to Alzheimer's disease (AD) has been lacking, particularly for our most susceptible segment of the population (i.e., those aged 80 and older). The proposed research addresses this gap and builds upon our experience in detailed neuropsychological studies along with advances with functional MRI studies of the medial temporal lobe for application to at-risk populations. With the increasing application of FMRI techniques to the study of AD, there is a growing need for quantitative measures that can more accurately reflect neural activity and its antecedent changes during the preclinical period of AD. The primary objectives of this project are to identify neuropsychological and neuroimaging changes in older adults at risk for the development of AD.
Our specific aims continue the focus on our highest known risk group (i.e., those aged 80 and above) and on genetic susceptibility (e.g., apolipoprotein E). Critical examination of another risk factor for progression to AD, Mild Cognitive Impairment, will also represent a new aim for this project.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG012674-15
Application #
8278666
Study Section
Special Emphasis Panel (ZRG1-BDCN-N (02))
Program Officer
Hsiao, John
Project Start
1994-04-20
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2014-05-31
Support Year
15
Fiscal Year
2012
Total Cost
$269,191
Indirect Cost
$74,829
Name
Veterans Medical Research Fdn/San Diego
Department
Type
DUNS #
933863508
City
San Diego
State
CA
Country
United States
Zip Code
92161
Bangen, Katherine J; Clark, Alexandra L; Werhane, Madeline et al. (2016) Cortical Amyloid Burden Differences Across Empirically-Derived Mild Cognitive Impairment Subtypes and Interaction with APOE ɛ4 Genotype. J Alzheimers Dis 52:849-61
Sheppard, David P; Graves, Lisa V; Holden, Heather M et al. (2016) Spatial pattern separation differences in older adult carriers and non-carriers for the apolipoprotein E epsilon 4 allele. Neurobiol Learn Mem 129:113-9
Edmonds, Emily C; Delano-Wood, Lisa; Jak, Amy J et al. (2016) "Missed" Mild Cognitive Impairment: High False-Negative Error Rate Based on Conventional Diagnostic Criteria. J Alzheimers Dis 52:685-91
Weissberger, Gali H; Gollan, Tamar H; Bondi, Mark W et al. (2015) Language and task switching in the bilingual brain: Bilinguals are staying, not switching, experts. Neuropsychologia 66:193-203
Edmonds, Emily C; Delano-Wood, Lisa; Galasko, Douglas R et al. (2015) Subtle Cognitive Decline and Biomarker Staging in Preclinical Alzheimer's Disease. J Alzheimers Dis 47:231-42
Nation, Daniel A; Edmonds, Emily C; Bangen, Katherine J et al. (2015) Pulse pressure in relation to tau-mediated neurodegeneration, cerebral amyloidosis, and progression to dementia in very old adults. JAMA Neurol 72:546-53
Edmonds, Emily C; Delano-Wood, Lisa; Clark, Lindsay R et al. (2015) Susceptibility of the conventional criteria for mild cognitive impairment to false-positive diagnostic errors. Alzheimers Dement 11:415-24
Bangen, Katherine J; Nation, Daniel A; Delano-Wood, Lisa et al. (2015) Aggregate effects of vascular risk factors on cerebrovascular changes in autopsy-confirmed Alzheimer's disease. Alzheimers Dement 11:394-403.e1
Bondi, Mark W; Edmonds, Emily C; Jak, Amy J et al. (2014) Neuropsychological criteria for mild cognitive impairment improves diagnostic precision, biomarker associations, and progression rates. J Alzheimers Dis 42:275-89
Edmonds, Emily C; Delano-Wood, Lisa; Galasko, Douglas R et al. (2014) Subjective cognitive complaints contribute to misdiagnosis of mild cognitive impairment. J Int Neuropsychol Soc 20:836-47

Showing the most recent 10 out of 72 publications