Assessment of the influence of cognition and cognitive processing speed on three tests of olfaction.

The extent to which measures of working memory, cognitive speed, and verbal retrieval are associated with performance on tests of olfaction was evaluated in a sample of 138 older adults. Structural equation modeling techniques indicated that verbal retrieval difficulties significantly affect performance on the University of Pennsylvania Smell Identification Test (UPSIT). Further, poor working memory and slow cognitive speed significantly affect performance on the UPSIT and the phenyl ethyl alcohol threshold test. The Sniff Magnitude Test was not influenced by any of the cognitive variables. Odor threshold and identification tasks may overestimate olfactory loss when cognitive impairment is not taken into account.