Device Description
The OMT provides a subjective assessment of odor discrimination in general and short-term odor memory in particular. This instrument is a 12-item, single-target, four-alternative, forced- choice test with nominal 10-, 30-, and 60-sec delay intervals. However, these delay intervals are not sacrosanct and can be modified by the test user according to his or her interests or needs.
The OMT is based on the match-to-sample paradigm. A unique feature of the OMT is the ease of presentation of the stimuli, since the test administrator must simply scratch open a set of micro- encapsulated odors with a pencil for the subject to sample at the appropriate time points. The micro- encapsulated odorants used in this test – banana, peppermint, rose, and peanut -- were chosen to be isointensive so that only the qualitative stimulus dimension is salient.
In this test, a target odorant is released by scratching the odorized label, which is then presented to the subject for sampling. After a given delay interval, four microencapsulated odorants (three of which are foils) are similarly released and presented at ~ five second 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, each subject is required to count aloud backwards by threes from 280 to minimize verbal rehearsal. The odorants used in the test are counter-balanced such that all odorants occur an equal number of times at each delay interval. The order of the delay intervals is the same for each subject and is as follows for the 12 respective items: 10, 30, 30, 60, 10, 60, 60, 30, 60, 30, 10, & 10 sec. The target odors (TO) and the response set choices (RC) for each of these 12 items are as follows (correct response in italics): (1) TO: PEA; RC: EA, PNUT, PEA, MINT; (2) TO: MIN RC: PEA, MINT, EA, PNUT; (3) TO: PNUT; RC: EA, PEA, MINT, PNUT; (4) TO: EA; RC: EA, PNUT, PEA, MINT; (5) TO: MINT; RC: MINT, EA, PEA, PNUT; (6) TO: PEA; RC: EA, PE