Subsets of a large cognitive battery better power clinical trials on early stage Alzheimer's disease.
OBJECTIVE
Cognitive batteries routinely used by the Alzheimer's disease (AD) research community may contain items that are uninformative for tracking disease progression to power clinical trials on early stage AD. We aim to identify the subsets of the most informative items from an existing cognitive battery to better power clinical trials on early AD.


METHODS
Longitudinal change in item scores from the battery was associated with the onset of mild cognitive impairment (MCI) in 1,513 elderly individuals. Items whose longitudinal changes were correlated with the onset of MCI were selected as informative for tracking the early cognitive progression.


RESULTS
226 items in the battery were annually assessed over a follow-up of up to 13 years. Changes of item scores over time from 187 items were significantly correlated with the onset of MCI. For clinical trials on preclinical AD and on MCI, informative items permit smaller or similar sample sizes as compared to the entire battery, whereas uninformative items require much larger sample sizes.


CONCLUSIONS
Longitudinal changes in item scores from about 17% of items in the cognitive battery are uninformative for tracking early disease progression. Clinical trials on early AD can be better powered using informative items rather than the entire battery.
Division of Biostatistics, Washington University in St. Louis, St. Louis, Mo., USA.
Chengjie
C
Xiong
Hua
H
Weng
David A
DA
Bennett
Patricia A
PA
Boyle
Raj C
RC
Shah
Scot
S
Fague
Charles B
CB
Hall
Richard B
RB
Lipton
John C
JC
Morris
D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D002986:Clinical Trials as Topic; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000523:psychology; D018450:Disease Progression; D006801:Humans; D009483:Neuropsychological Tests; D011594:Psychometrics; D015203:Reproducibility of Results