demonstrate that CSF Tau levels are w2X higher in mild-to-moderate AD compared to age-matched controls. In addition, this increase in CSF Tau is detected prior to the onset of clinical symptoms, and thus is predictive of the conversion from predementia (MCI) to clinical disease. Despite the importance as a diagnostic biomarker, the molecular nature of Tau present in CSF is not known. Methods: We have employed CSF denaturation cou- pled with reverse-phase HPLC in order to enrich and concentrate Tau and to further characterize the CSF Tau profile. Individual fractions from pooled AD and control CSF samples were analyzed by SDS-PAGE/Western blot (WB) using various anti-Tau antibodies or by using in-house, research-grade Tau ELISAs. Results: Multiple fragments of Tau, with apparent MW sizes ranging from w15 kD to 40 kD, were identified by WB using an antibody that recognizes the mid-domain of Tau, but not an isotype control IgG. A subset of these bands was recognized using an antibody specific for the N-terminal of Tau. In contrast, relatively low levels of C-terminal-contain- ing fragments were detected as demonstrated using a C-terminal specific antibody. Tau ELISA results confirmed the WB data and demonstrated that differences in Tau levels between AD and control CSF are more prom- inent in specific fractions, corresponding to certain apparent molecular weight Tau fragments. Conclusions: Our results demonstrate the existence of multiple Tau fragments in CSF and suggest that a subset of these frag- ments are increased in AD CSF. These particular Tau fragments may have utility as disease and/or pharmacodynamic biomarkers. P2-040 PLASMA CERAMIDE CONCENTRATIONS ARE ASSOCIATED WITH CHANGE IN VERBAL MEMORY PERFORMANCE IN PATIENTS UNDERTAKING CARDIAC REHABILITATION Krista Lanctot 1 , Mahwesh Saleem 1 , Veera Vankata Ratnam Bandaru 2 , Nathan Herrmann 1 , Walter Swardfager 1 , Michelle Mielke 3 , Norman Haughey 2 , Paul Oh 4 , 1 Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2 Johns Hopkins University School of Medicine, Baltimore, Maryland, United States; 3 Mayo Clinic, Rochester, Minnesota, United States; 4 Toronto Rehabilitation Institute, Toronto, Ontario, Canada. Background: Coronary artery disease (CAD) and related risk factors have been associated with increased risks of mild cognitive impairment and pro- gression to dementia. A decline in verbal memory performance is a key marker of cognitive impairment in CAD, although deterioration may be miti- gated in individuals undertaking exercise interventions. Accumulating evi- dence suggests that long-chain ceramides may play a role in pathological neurodegeneration by mediating cell death mechanisms. Higher concentra- tions of ceramides have been associated with the development and progres- sion of CAD but their relationship with memory performance has not been assessed in this population. Methods: Patients with CAD were interviewed at entry and completion of cardiac rehabilitation (CR). The California Verbal Learning Test 2 nd ed. (CVLT-II) was administered at entry and after 1 year to assess memory. Z-scores were calculated from the long-delay free recall (LDFR) outcome of the CVLT-II word list based on age, gender and educa- tion matched norms. Baseline plasma ceramide (d18:0/16:0-d18:0/26:1) concentrations were measured from fasting plasma samples using HPLC- coupled electrospray ionization tandem mass spectrometry. Repeated mea- sures general linear models were used to determine the association between baseline plasma ceramides and the change in LDFR Z-scores between the baseline and follow-up time points, controlling for age and body mass index (BMI). Pearson correlations were used to determine the direction of the as- sociations using one-year LDFR change Z-scores. Results: Patients with CAD (n ¼ 34, mean age 62 6 9 years, 85% male, total education 17 6 3 years) showed improved verbal memory performance after 1 year of CR (mean change LDFR Z-score ¼ 0.88 6 0.76). Higher baseline d18:1/22:0 (F 1,30 ¼ 5.140, P ¼ 0.027) and d18:1/24:0 (F 1,30 ¼ 4.157, P ¼ 0.050) con- centrations were significantly associated with less improvement in verbal memory performance over 1 year of CR. Conclusions: Higher baseline d18:1/22:0 and d18:1/24:0 concentrations predicted less improvement in verbal memory performance over 1 year of CR. These preliminary findings suggest that plasma ceramides may be possible biomarkers of cognitive re- sponse to CR in CAD patients. The need for a prospective longitudinal study to explore the association between ceramides and cognitive function in CAD patients who are likely to have aberrant ceramide metabolism is strongly supported. P2-041 VISUAL CONTRAST SENSITIVITY AS A NOVEL BIOMARKER: DISCRIMINATIVE ANALYSIS USING ELASTIC NET TO CLASSIFY ALZHEIMER’S DISEASE, MCI AND OLDER ADULTS WITH COGNITIVE COMPLAINTS Jingwen Yan 1 , Taiyong Li 2 , Brenna McDonald 3 , Shannon Risacher 3 , Darrell WuDunn 4 , Martin Farlow 5 , Susan M. Pepin 6 , Laura Flashman 7 , Heather Wishart 6 , Robert Santulli 7 , Andrew Saykin 8 , Li Shen 3 , 1 Indiana University, Indianapolis, Indiana, United States; 2 Southwestern University of Finance and Economics, Chengdu, China; 3 Indiana University School of Medicine, Indianapolis, Indiana, United States; 4 Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States; 5 Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana, United States; 6 Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States; 7 Dartmouth Medical School, Lebanon, New Hampshire, United States; 8 Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, United States. Background: Visual deficits in contrast sensitivity, assessed using frequency doubling technology (FDT), have been studied in Alzheimer’s disease (AD), and been related to brain atrophy measures and cognitive functioning [1,2]. This study aims to examine the effectiveness of advanced classification meth- odology for classifying early and prodromal stages of disease (AD, mild cog- nitive impairment (MCI), older adults with cognitive complaints, healthy controls) using visual contrast sensitivity test data. Methods: Participants (n ¼ 77) included those with mild AD (n ¼ 9), amnestic MCI (n ¼ 27), older adults with informant-verified cognitive complaints but no significant Figure 1. Visual field maps of classifier weights of 110 regional measures: (a) HC vs AD, (b) CC vs AD, and (c) MCI vs AD. Blue (red) indicates de- creased (increased) level in cases. Poster Presentations: P2 P277