TY - JOUR
T1 - Alzheimer disease pathology in subjects without dementia in 2 studies of aging
T2 - The nun study and the adult changes in thought study
AU - Santacruz, Karen S.
AU - Sonnen, Joshua A.
AU - Pezhouh, Maryam Kherad
AU - Desrosiers, Mark F.
AU - Nelson, Peter T.
AU - Tyas, Suzanne L.
PY - 2011/10
Y1 - 2011/10
N2 - Individuals with antemortem preservation of cognition who show autopsy evidence of at least moderate Alzheimer disease (AD) pathology suggest the possibility of brain reserve, that is, functional resistance to structural brain damage. This reserve would, however, only be relevant if the pathologic markers correlate well with dementia. Using data from the Nun Study (n = 498) and the Adult Changes in Thought (ACT) Study (n = 323), we show that Braak staging correlates strongly with dementia status. Moreover, participants with severe(Braak stage V-VI) AD pathology who remained not demented represent only 12% (Nun Study) and 8% (ACT study) of nondemented subjects. Comparison of these subjects to those who were demented revealed that the former group was often significantly memory-impaired despite not being classified as demented. Most of these nondemented participants showed only stage V neurofibrillary pathology and frontal tangle counts that were slightly lower than a comparable (Braak stage V) dementia group. In summary, these data indicate that, in individuals with AD-type pathology who do not meet criteria for dementia, neocortical neurofibrillary tangles are somewhat reduced and incipient cognitive decline is present. Our data provide a foundation for helping to define additional factors that may impair, or be protective of, cognition in older adults.
AB - Individuals with antemortem preservation of cognition who show autopsy evidence of at least moderate Alzheimer disease (AD) pathology suggest the possibility of brain reserve, that is, functional resistance to structural brain damage. This reserve would, however, only be relevant if the pathologic markers correlate well with dementia. Using data from the Nun Study (n = 498) and the Adult Changes in Thought (ACT) Study (n = 323), we show that Braak staging correlates strongly with dementia status. Moreover, participants with severe(Braak stage V-VI) AD pathology who remained not demented represent only 12% (Nun Study) and 8% (ACT study) of nondemented subjects. Comparison of these subjects to those who were demented revealed that the former group was often significantly memory-impaired despite not being classified as demented. Most of these nondemented participants showed only stage V neurofibrillary pathology and frontal tangle counts that were slightly lower than a comparable (Braak stage V) dementia group. In summary, these data indicate that, in individuals with AD-type pathology who do not meet criteria for dementia, neocortical neurofibrillary tangles are somewhat reduced and incipient cognitive decline is present. Our data provide a foundation for helping to define additional factors that may impair, or be protective of, cognition in older adults.
KW - Adult Changes in Thought study
KW - Alzheimer disease
KW - Brain reserve
KW - Dementia
KW - Nun Study
KW - Preclinical
KW - Presymptomatic
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UR - http://www.scopus.com/inward/citedby.url?scp=80053352053&partnerID=8YFLogxK
U2 - 10.1097/NEN.0b013e31822e8ae9
DO - 10.1097/NEN.0b013e31822e8ae9
M3 - Article
C2 - 21937909
AN - SCOPUS:80053352053
SN - 0022-3069
VL - 70
SP - 832
EP - 840
JO - Journal of Neuropathology and Experimental Neurology
JF - Journal of Neuropathology and Experimental Neurology
IS - 10
ER -