2010). Classifiers built from FDG-PET data might perform somewhat better. For example, in a study evaluating biomarkers from the ADNI study for predicting worsening among MCI patients, glucose metabolism of the entorhinal or retrosplenial cortices were significantly correlated with change in MMSE over a 2-year period. Of the MRI measures, only retrosplenial gray matter reductions were useful for predicting change, but did Inhibitors,research,lifescience,medical so for both MMSE and CDR sum of boxes score (Walhovd et al. 2010). As a clinical tool,

PET scans are useful for predicting progressive dementia, and may have sensitivity of 93% and specificity up to 76% when interpreted by an expert nuclear medicine physician (Silverman et al. 2001). However, it might be difficult to replicate these results in the absence of such an expert reader. This work has several limitations. First, classifiers could incorporate other types of data, such as genetic testing or neuropsychological measures. Other investigators have evaluated

a combination of PET and neuropsychological Inhibitors,research,lifescience,medical data for predicting changes in cognition and Inhibitors,research,lifescience,medical daily BI-D1870 cost functioning, with the results suggesting that FDG-PET makes an independent contribution to such a model and might be superior to cognitive testing alone (Landau et al. 2010, 2011). One of the classifiers presented here was enhanced by the addition of FAQ score, a brief informant-based measure of daily functioning. It remains to be seen, however, whether cosine similarity scores as derived here can make an additive contribution to cognitive testing for diagnosing AD or predicting cognitive and functional decline. Future work will look to combinations Inhibitors,research,lifescience,medical of imaging measures, apolipoprotein E genotyping, and neuropsychological test scores for performing prognostications. Second, although classifiers using logistic regression have the advantage of being familiar to most clinicians, advances Inhibitors,research,lifescience,medical in machine learning (e.g., support vector machines) could add substantially to the quality of diagnoses and prognostications generated using the methods outlined here. Third,

these data were acquired on a highly specific subset of patients with AD and nondementia memory impairment. Classifiers trained with these methods might not perform as well on a more heterogeneous patient population, such as the general population of patients presenting to a given memory disorders clinic, SPTLC1 because other disease entities (vascular dementia, dementia with Lewy bodies) and other forms of nondementia cognitive impairment (executive dysfunction, progressive aphasia) may render the cosine similarity scores derived by this method less relevant. On the other hand, the method introduced here is meant to have general utility and could theoretically be adapted to apply to any of these problems. IR is a vast and rapidly developing field with real and highly visible advances.