Smell Suprathreshold Test

The odor memory test (OMT) is a test of short-term odor memory and discrimination that employs 10-, 30-, and 60-s delay intervals between the presentation of a target odorant and a set of odors from which the target is to be selected. The target odorant is initially released by scratching an odorized label that is then presented to the subject for sampling. After a given delay interval, the 4 subsequent odorants (the target and 3 foils) are similarly released and presented at approximately 5-s intervals. The subject's task is to report which odor in the odor response set is the same as the target stimulus. During the delay interval, the subject counts aloud backward by 3 from 280 to minimize verbal rehearsal. The presentation order of the stimuli is counterbalanced such that 1) all target odorants occur an equal number of times at each delay interval, 2) each target odorant is represented at a given delay interval once in each of the 4 possible response positions (i.e., a, b, c, and d), and 3) all 4 odorants are presented in the first, second, and third segments of the test. The test–retest reliability of the OMT is above 0.70.