Effect of Alzheimer disease risk on brain function during self-appraisal in healthy middle-aged adults.
BACKGROUND
Asymptomatic middle-aged adult children of patients with Alzheimer disease (AD) recently were found to exhibit functional magnetic resonance imaging (fMRI) deficits in the mesial temporal lobe during an encoding task. Whether this effect will be observed on other fMRI tasks is yet unknown. This study examines the neural substrates of self-appraisal (SA) in persons at risk for AD. Accurate appraisal of deficits is a problem for many patients with AD, and prior fMRI studies of healthy young adults indicate that brain areas vulnerable to AD such as the anterior mesial temporal lobe and posterior cingulate are involved during SA tasks.


OBJECTIVE
To determine whether parental family history of AD (hereafter referred to as FH) or presence of the epsilon4 allele of the apolipoprotein E gene (APOE4) exerts independent effects on brain function during SA.


METHODS
Cross-sectional factorial design in which APOE4 status (present vs absent) was one factor and FH was the other. All participants received cognitive testing, genotyping, and an fMRI task that required subjective SA decisions regarding trait adjective words in comparison with semantic decisions about the same words.


METHODS
An academic medical center with a research-dedicated 3.0-T MR imaging facility.


METHODS
Cognitively normal middle-aged adults (n = 110), 51 with an FH and 59 without an FH.


METHODS
Blood oxygen-dependent contrast measured using T2*-weighted echo-planar imaging.


RESULTS
Parental family history of AD and APOE4 status interacted in the posterior cingulate and left superior and medial frontal regions. There were main effects of FH (FH negative > FH positive) in the left hippocampus and ventral posterior cingulate. There were no main effects of APOE genotype.


CONCLUSIONS
Our results suggest that FH may affect brain function during subjective SA in regions commonly affected by AD. Although the participants in this study were asymptomatic and middle-aged, the findings suggest that there may be subtle alterations in brain function attributable to AD risk factors.
Johnson
Sterling C
SC
Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, 2500 Overlook Terrace, Madison, WI 53705, USA. scj@medicine.wisc.edu
Ries
Michele L
ML
Hess
Timothy M
TM
Carlsson
Cynthia M
CM
Gleason
Carey E
CE
Alexander
Andrew L
AL
Rowley
Howard A
HA
Asthana
Sanjay
S
Sager
Mark A
MA
D000328:Adult; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology*; D053327:Apolipoprotein E4 / Q000235:genetics; D001364:Awareness / Q000502:physiology*; D001921:Brain / Q000503:physiopathology*; D002648:Child; D016241:Child of Impaired Parents / Q000523:psychology / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D003657:Decision Making / Q000502:physiology; D005190:Family; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006304:Health Status; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010100:Oxygen / Q000097:blood; D012307:Risk Factors; D013702:Temporal Lobe / Q000503:physiopathology
D053327:Apolipoprotein E4; D010100:Oxygen