Odorant confusion matrix: the influence of patient history on patterns of odorant identification and misidentification in hyposmia

The odorant confusion matrix (OCM) is an odorant identification test in whi ch the number of correct odorant identifications quantifies the level of ol factory function. As with other confusion matrices, the OCM reflects distor tions of sensory perception as errors in identification Previous work with the OCM suggests that, within an individual, hyposmia is associated with a stable shift in odorant perception. The current study examined whether cons istent shifts in odorant perception are also characteristic of the various pathologies that lead to an olfactory loss. In a retrospective study, OCM r esponse patterns for 135 hyposmic patients were fit into a five-dimensional space in which the distances between subjects reflected the dissimilaritie s between their OCM response patterns. Multivariate regression was performe d relating position in the five-dimensional space to each of 11 factors rep resenting 33 demographic and medical history variables. One factor, named c ongestion (gathering the variables of past polyposis, current polyposis, an d current nasal obstruction due to swelling), was significantly indicative of patterns of responses on the OCM, independent of the level of hyposmia. These data suggest that conductive olfactory lass may be associated with al terations in odorant perception, which are reflected inconsistent odorant c onfusions. Such alterations in perception may eventually serve as a basis f or a clinical test to provide differential diagnoses as to the sources of o lfactory losses. (C) 2001 Elsevier Science Inc. All rights reserved.