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O4‐10‐05: The effect of vascular risk factors on cognition in older adults: Data from the AIBL study
Author(s) -
Restrepo Carolina,
Saling Michael,
Yates Paul,
Villemagne Victor,
Ames David,
Bush Ashley,
Faux Noel,
Martins Ralph,
Masters Colin,
Rowe Christopher,
Szoeke Cassandra,
Ellis Kathryn
Publication year - 2012
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.2012.05.1693
Subject(s) - medicine , gerontology , cognition , cognitive decline , neuropsychology , dementia , body mass index , risk factor , cohort , diabetes mellitus , biomarker , disease , clinical psychology , psychology , psychiatry , endocrinology , biology , biochemistry
version to Alzheimer’s disease (AD). Partially ordered sets (POSETS) are classification models, which are useful for representing the inherent relationships between specific cognitive functions and neuropsychological (NP) measures. This allows for statistical linkage of response patterns to cognitive profiles of functioning that can be used to understand how different cognitive functions serve as markers for AD conversion. Methods: To identify subgroups within MCI with high likelihood of conversion to AD within 24 months by analyzing cognitive data from the Alzheimer’s disease cooperative study (ADCS) MCI trial through application of POSETmethodology. We have initially considered 513MCI patients that were followed for 24 months. Response patterns to selected NP measures are linked to cognitive profiles of functioning using POSETs, which are then clustered and stratified by APoE4 status. Results: Unsurprisingly, among cognitive functions considered, impairment with episode memory (EM) is most associated with conversion within 24 months. Functioning level is determined by classification to profiles and strength of classification, as reflected by Bayesian posterior probabilities. The conversion rate of those with lower levels of EM and APOE-ε4 is 65.2%, E.g. lower level functioning is characterized by relatively poor performance on the ADAS-Cog delayed recall, Logical Memory, and NYU Paragraph. In contrast, for those ApoE4 subjects who are not at a lower level of EM functioning (e.g. perform relatively well on ADAS-Cog delayed recall) are at a significantly lower conversion rate (23.2%; Fisher’s exact test p-value < 0.001). Moreover, for those with higher levels of EM functioning (e.g. perform relatively well on the delayed recall measures) and without APOE-ε4, the observed conversion rate is only 7.8%. In an ROC analysis, the AUC for EM functioning level is 0.789. Other cognitive functions such as cognitive flexibility, working memory, processing speed, and word fluency do not appear to be significantly related to higher conversion rates. Conclusions: EM functioning and APOE-ε4 status are strongly related to MCI conversion to AD within 24 months. This corroborates the great heterogeneity in conversion rates found from a POSET-based analysis of ADNI cognitive data.