Cognitive reserve hypothesis: Pittsburgh Compound B and fluorodeoxyglucose positron emission tomography in relation to education in mild Alzheimer's disease.
OBJECTIVE
The reduced risk for Alzheimer's disease (AD) in high-educated individuals has been proposed to reflect brain cognitive reserve, which would provide more efficient compensatory mechanisms against the underlying pathology, and thus delayed clinical expression. Our aim was to find possible differences in brain amyloid ligand 11C-labeled Pittsburgh Compound B ([11C]PIB) uptake and glucose metabolism in high- and low-educated patients with mild AD.


METHODS
Twelve high-educated and 13 low-educated patients with the same degree of cognitive deterioration were studied with PET using [11C]PIB and 18F-fluorodeoxyglucose as ligands. The between-group differences were analyzed with voxel-based statistical method, and quantitative data were obtained with automated region-of-interest analysis.


RESULTS
High-educated patients showed increased [11C]PIB uptake in the lateral frontal cortex compared with low-educated patients. Moreover, high-educated patients had significantly lower glucose metabolic rate in the temporoparietal cortical regions compared with low-educated patients.


CONCLUSIONS
Our results suggesting more advanced pathological and functional brain changes in high-educated patients with mild AD are in accordance with the brain cognitive reserve hypothesis and point out the importance of development of reliable markers of underlying AD pathology for early AD diagnostics.
Kemppainen
Nina M
NM
Turku Positron Emission Tomography Centre, University of Turku, Turku, Finland.
Aalto
Sargo
S
Karrasch
Mira
M
Någren
Kjell
K
Savisto
Nina
N
Oikonen
Vesa
V
Viitanen
Matti
M
Parkkola
Riitta
R
Rinne
Juha O
JO
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D000814:Aniline Compounds / Q000378:metabolism; D002250:Carbon Radioisotopes; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D004198:Disease Susceptibility / Q000378:metabolism*; D004522:Educational Status; D004734:Energy Metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D058225:Plaque, Amyloid / Q000378:metabolism* / Q000473:pathology; D049268:Positron-Emission Tomography; D020127:Recovery of Function; D013844:Thiazoles / Q000378:metabolism
C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D000814:Aniline Compounds; D002250:Carbon Radioisotopes; D013844:Thiazoles; D019788:Fluorodeoxyglucose F18; D005947:Glucose