Olfactory deficits in frontotemporal dementia as measured by the Alberta Smell Test.

ABSTRACT

The study of olfaction in neurodegeneration has primarily focused on Alzheimer's disease. Research of olfaction in frontotemporal dementia (FTD) has generally not been empirically studied. The current study compared olfaction in FTD to major depressive disorder (MDD) using the Alberta Smell Test (AST). Independent-samples t test results suggested olfaction in FTD was impaired when compared with participants diagnosed with MDD. The AST Total score (out of 20 trials) significantly predicted the diagnostic group and accounted for 40% of the variance in diagnostic group status with an odds ratio of 20.08. Results suggested that a cutoff of ≤2/20 differentiated FTD from MDD with 94% accuracy (91% sensitivity, 97% specificity) and a cutoff of ≤1/20 differentiated the groups with a 95.5% hit rate (91% sensitivity, 100% specificity). Results confirmed olfactory identification deficits in FTD and suggested that the AST is an effective tool for the demarcation of FTD from MDD. This is especially important due to the potential for significant overlap in the behavioral/emotional phenotype and cognitive deficits between the two disorders when presented with early stages of FTD.