Perceived loss of memory ability and cerebral metabolic decline in persons with the apolipoprotein E-IV genetic risk for Alzheimer disease.
BACKGROUND
Concerns about age-related memory loss are greater in persons who have the apolipoprotein E-IV (APOE4) genetic risk for Alzheimer disease, but the correlation between the degree of concerns and future cerebral metabolic decline is unknown.


OBJECTIVE
To investigate whether the degree of self-perceived memory loss is associated with regional cerebral metabolic decline.


METHODS
Longitudinal study.


METHODS
Aging and Memory Research Center, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles.


METHODS
Thirty right-handed, cognitively intact, middle-aged and older adults (age range, 50-82 years) with age-associated memory complaints, 14 of whom were carriers of the apolipoprotein E-IV allele, were recruited for longitudinal study.


METHODS
At baseline, we administered a standardized neuropsychological battery and assessed self-appraisal of memory functioning using the Memory Functioning Questionnaire, which yields 4 factor scores indicating frequency of forgetting, seriousness of forgetting, retrospective functioning, and mnemonics use. Regional cerebral glucose metabolism was determined using fluorodeoxyglucose F18-positron emission tomography at baseline and after 2 years.


RESULTS
At baseline, APOE4 carriers and noncarriers did not differ significantly on objective memory measures or on Memory Functioning Questionnaire factor scores. However, the factor score for frequency of forgetting significantly correlated with global cerebral metabolic decline in all subjects regardless of APOE4 genetic risk (P = .01). By contrast, the factor score for mnemonics use significantly correlated with metabolic decline in the temporal regions in APOE4 carriers but not in noncarriers (P = .03).


CONCLUSIONS
The degree of perceived memory loss correlates with subsequent global cerebral metabolic decline for APOE4 carriers and noncarriers; hence, memory complaints may reflect underlying cerebral metabolic changes. Compensatory strategies, as reflected by more frequent mnemonics use in APOE4 carriers, may reflect underlying metabolic changes in the brain regions associated with prodromal Alzheimer disease. Self-reported mnemonics use may be helpful in identifying persons for clinical monitoring.
Ercoli
Linda
L
Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, 90024, USA. lercoli@mednet.ucla.edu
Siddarth
Prabha
P
Huang
Sung-Cheng
SC
Miller
Karen
K
Bookheimer
Susan Y
SY
Wright
Benjamin C
BC
Phelps
Michael E
ME
Small
Gary
G
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000235:genetics* / Q000378:metabolism; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D001364:Awareness; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D003072:Cognition Disorders / Q000175:diagnosis / Q000378:metabolism; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality / Q000502:physiology; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D005838:Genotype; D005947:Glucose / Q000378:metabolism; D006304:Health Status; D006579:Heterozygote; D006801:Humans; D008137:Longitudinal Studies; D008569:Memory Disorders / Q000175:diagnosis* / Q000378:metabolism / Q000523:psychology; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D011795:Surveys and Questionnaires
D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D019788:Fluorodeoxyglucose F18; D005947:Glucose