Premium
P1‐189: Conversion to dementia over a five‐year period among patients with mild cognitive impairment in a Polish follow‐up study
Author(s) -
Gabryelewicz Tomasz,
Styczynska Maria,
Barczak Anna,
Wasiak Boguslaw,
Pfeffer Anna,
Luczywek Elzbieta,
Barcikowska Maria
Publication year - 2008
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2008.05.777
Subject(s) - dementia , neuropsychology , medicine , vascular dementia , cognitive impairment , cognition , cognitive decline , disease , pediatrics , psychiatry , psychology
90% power. A neuroimaging profile indicative of pre-clinical AD was determined by a linear classifier trained on discriminating patients diagnosed with AD from normal controls subjects. Results: A trial using the recruitment criteria of the ADNI study would expect a mean placebo arm rate of decline of 0.6 MMSE points/year and require a sample size of 1000 subjects/arm to detect a 50% reduction in mean rate of decline. A trial restricting to subjects with an ApoE E4 allele would expect a mean rate of decline 1.1 points/year and require 395 subjects/ arm to detect a 50% reduction in mean decline. A trial restricting to subjects with a neuroimaging profile consistent with pre-clinical AD would expect a mean rate of decline 1.4 points/year and require 261 subjects/arm. Conclusions: Enrichment strategies can improve the efficiency of secondary prevention trials. Statistical considerations of power and sample size are relevant to discussions of the relative merit of different enhancement strategies.