normal age-related decline in processing speed only (n=337) (Ta- ble 1, Figure 1). ... dichotomized as negative (normal) or positive (abnormal) accord- .... dividuals on the basis of elevated amyloid (Ab) on PET imaging; however, the ...
Podium Presentations: Tuesday, July 26, 2016
Figure 2. Mean global atrophy in three clusters. Full model also included age, gender, and intracranial
Table 1 Mean (SD) demographics and annual rates of change on cognitive measures included in cluster analysis
N (%) 188 (28%) 152 (22%) Demographics Age at baseline 54.9 (6.2) 55.1 (6.6) Gender (n Female; % 114(61%) 107 (70%) Female) Education (years) 16.5 (2.9) 15.8(2.9) WRAT-III Reading 106.1 (9.7) 103.1 (9.5) (standardized score) Depressive symptoms at 6.9 (7.2) 6.0 (6.0) baseline (CESD 0-38) Parental history of AD 147 (78%) 120 (79%) APOE (e4 carrier/non-carrier) 86 (46%) 56 (37%) CDR at most recent visit 37 (22%) 21 (16%) (% 0.5) Consensus Diagnosis at 58 (35%) 24(19%) most recent visit (% MCI or dementia) Clustering Variables RAVLT Total 1-5 slope -.10 (.10) -.06 (.09) WMS-R LM Delay slope -.06 (.09) .004 (.12) BVMT-R Immediate slope .10 (.08) .19 (.07) Trails B (log transformed) .002 (.003) .002 (.002) slope WAIS-R Digit Symbol -.65 (.18) -.65 (.18) Coding slope Boston Naming Test slope .06 (.02) .09 (.03)
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mixed-effects regression, unconditional growth models were conducted for six neuropsychological variables, and the fixed and random effect estimates were combined to obtain slope estimates for each participant. Hierarchical cluster analysis was conducted on slope estimates, and resulting clusters were compared on slopes, intercepts, demographics, AD risk, and clinical outcomes. A subset underwent MRI scans (n¼235) and cerebrospinal fluid assays (n¼88). ANCOVA models (covarying age and gender) compared clustered groups on brain structure and AD biomarkers. Results: Cluster analysis resulted in three groups: 1) Multi-domain group declining on learning, memory, and executive function measures (n¼188), 2) dysexecutive group with mild decline in verbal learning and executive functioning (n¼152), and 3) group with normal age-related decline in processing speed only (n¼337) (Table 1, Figure 1). The multi-domain cluster was older (F¼19.32, p
