A standardized technique for establishing onset and duration of symptoms of Alzheimer's disease
M. Sano, D. P. Devanand, M. Richards, L. W. Miller, K. Marder, K. Bell, G. Dooneief, F. W. Bylsma, G. Lafleche, M. Albert and al. et
Department of Neurology, College of Physicians & Surgeons of Columbia University, New York, NY, USA.
OBJECTIVES: 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. DESIGN: 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. SUBJECTS: 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. CONCLUSION: This instrument provides a
reliable procedure for standardizing the estimation of duration of illness
based on retrospective report.