Contribution of informant and patient ratings to the accuracy of the mini-mental state examination in predicting probable Alzheimer's disease.
OBJECTIVE
To determine whether the accuracy of the Mini-Mental State Examination (MMSE) in predicting future Alzheimer's disease (AD) could be improved by the addition of patient and informant ratings of cognitive difficulties.


METHODS
An inception cohort of nondemented patients followed longitudinally for 2 years.


METHODS
Patients referred to a university teaching hospital research investigation by their family physicians because of concerns about memory impairment.


METHODS
One hundred sixty-five community-residing patients were included who did not have dementia or any identifiable cause for memory impairment. After 2 years, 29 met criteria for AD, and 95 were not demented.


METHODS
Baseline assessments included MMSE, an Informant Rating Scale, and a Patient Rating Scale of cognitive difficulties. After 2 years, patients were diagnosed following the reference standard for probable AD. Diagnosticians were blind to baseline scores.


RESULTS
Age and education were included in all analyses as covariates. The best logistic regression model included the Informant Rating Scale and the MMSE (sensitivity = 83%, specificity = 79%). An empirically reduced six-item model that included two items each from the MMSE, the Patient Rating Scale, and the Informant Rating Scale produced a significantly better model than the one with the full test scores (sensitivity = 90%, specificity = 94%).


CONCLUSIONS
Results indicate that inclusion of informant ratings with the MMSE significantly improved its accuracy in the prediction of probable AD. Replication in a new prospective cohort of nondemented patients is necessary to confirm these findings.
Tierney
Mary C
MC
Geriatric Research Unit, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Ontario, Canada. mary.tierney@sw.ca
Herrmann
Nathan
N
Geslani
Daphne M
DM
Szalai
John P
JP
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D015331:Cohort Studies; D005190:Family / Q000523:psychology*; D033062:Friends / Q000523:psychology*; D015577:Geriatric Assessment; D006801:Humans; D009483:Neuropsychological Tests / Q000592:standards*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results