Minnesota memory project: Use of the Alberta Smell Test in a longitudinal aging cohort [abstract]
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Background: The Minnesota Memory Project is a longitudinal study investigating cognitive and lifestyle factors associated with advancing age. Gathering information about memory function and health prior to diagnosis can help identify ways to make earlier diagnoses, identify risk factors of memory loss, and develop programs to help prevent or delay symptoms. Olfactory deficits are an early feature of cognitive impairment and have been linked to disease progression. The Alberta Smell Test (AST) is a fast and cost-effective method of evaluating olfactory function. Methods: Adults living in the community were recruited for participation in the Minnesota Memory Project. Annual assessments included cognitive screening (Montreal Cognitive Assessment; MoCA), neuropsychological testing, physical measurements, and self-report inventories of health history and lifestyle characteristics. The AST, an optional sub-study, investigates sense of smell by asking participants to identify odors from scented felt tipped markers. This sensitivity analysis examines the accuracy of the AST in detecting cognitive impairment using MoCA scores. Results: Subjects who completed the AST (N=134) ranged in age from 50–92 (average 70) and were generally female (70.1%), white (98.5%), and without a diagnosis of memory loss (97.8%). The average MoCA score was 26.7 (SD 2.3) and the average AST total score was 8.6 (SD 4.2). Using a cutoff of 25 to indicate potential cognitive impairment, 31 of the subjects had low MoCA scores (23.1%). Total AST score (out of 20 trials) and minimum unirhinal score (out of 10 trials) were significantly worse in the low MoCA group. This group also tended to be older (mean 75.4) and have fewer females (55.8%). Both AST scores significantly predicted the MoCA group, accounting for 8-10% of the variance in MoCA group status. ROC curve results demonstrated that the AST minimum unirhinal score may be a slightly better predictor of MoCA group than AST total score (AUC=0.646 and 0.668, respectively). Conclusions: Results suggest that the AST is a potential screening tool for cognitive impairment. The Minnesota Memory Project will continue to collect longitudinal data on participants in increase capacity for testing this association.