The AD8: a brief informant interview to detect dementia.
BACKGROUND
Brief measures that accurately discriminate normal cognitive aging from very mild dementia are lacking. Cognitive tests often are insensitive to very mild dementia. Informant-based measures may be more sensitive in detecting early dementia.


OBJECTIVE
To identify informant-reported clinical variables that differentiate cognitively normal individuals from those with very mild dementia.


METHODS
A 55-item battery of informant queries regarding an individual's cognitive status was derived from a semistructured interview and a consensus panel of dementia experts. The battery was evaluated with informants for 189 consecutive participants of a longitudinal study of memory and aging and compared with an independently obtained Clinical Dementia Rating (CDR) score for the participant. Multiple regression and receiver operator characteristic curves assessed subsets of the items to discriminate between CDR 0 (no dementia) and CDR 0.5 (very mild dementia).


RESULTS
The final version (AD8) querying memory, orientation, judgment, and function was administered to an additional sample of 112 CDR 0 and 68 CDR 0.5 participants. Using a cut-off of two items endorsed, the area under the curve was 0.834, suggesting good to excellent discrimination, sensitivity was 74%, and specificity was 86% (prevalence of 0.38 for very mild dementia). Inclusion of 56 additional individuals with mild to severe dementia (increasing dementia prevalence to 0.53) increased sensitivity to 85%.


CONCLUSIONS
The AD8 is a brief, sensitive measure that reliably differentiates between nondemented and demented individuals. Use of the AD8 in conjunction with a brief assessment of the participant could improve diagnostic accuracy in general practice.
Galvin
J E
JE
Department of Neurology, Alzheimer Disease Research Center, Washington University, St. Louis, MO 63108, USA. galvinj@neuro.wustl.edu
Roe
C M
CM
Powlishta
K K
KK
Coats
M A
MA
Muich
S J
SJ
Grant
E
E
Miller
J P
JP
Storandt
M
M
Morris
J C
JC
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D003704:Dementia / Q000175:diagnosis* / Q000523:psychology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000523:psychology; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards*; D011237:Predictive Value of Tests; D011446:Prospective Studies