A standardized technique for establishing onset and duration of symptoms of Alzheimer's disease.
OBJECTIVE
To develop an informant-based semistructured interview to determine the onset and duration of symptoms of Alzheimer's disease, and to use this instrument with informants to characterize a cohort of mildly impaired patients with Alzheimer's disease.


METHODS
In study 1, interrater and interinformant reliability was examined for the date of onset and the order of appearance for specific symptoms that were elicited by the semistructured onset interview. In study 2, the instrument was used to characterize disease onset in a cohort of patients with Alzheimer's disease who were participating in a large multicenter study.


METHODS
Informants of patients with Alzheimer's disease.


RESULTS
In study 1, interrater reliability for duration of illness was excellent (intraclass correlation coefficient = .99, P < .001), and interinformant reliability was good (intraclass correlation coefficient = .86, P < .001). Agreement for the presence of a given symptom was highest for those that were most commonly reported (eg, memory and performance difficulty). In study 2, 89% of the cohort had memory problems, and 63.9% had performance difficulties as the first or second symptom. Depression and language problems were less commonly reported. Psychosis and behavioral disturbances were rarely reported as the first problem.


CONCLUSIONS
This instrument provides a reliable procedure for standardizing the estimation of duration of illness based on retrospective report.
Sano
M
M
Department of Neurology, College of Physicians & Surgeons of Columbia University, New York, NY, USA.
Devanand
D P
DP
Richards
M
M
Miller
L W
LW
Marder
K
K
Bell
K
K
Dooneief
G
G
Bylsma
F W
FW
Lafleche
G
G
Albert
M
M
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D015337:Multicenter Studies as Topic; D009483:Neuropsychological Tests; D015588:Observer Variation