OLFACTORY EVENT-RELATED POTENTIALS TO AMYL ACETATE IN CONGENITAL ANOSMIA

Olfactory function was evaluated by olfactory event-related potentials and standardized psychophysical measures including the Smell Identifi cation Test and odor detection threshold tests for 3 chemosensory stim ulants in 9 subjects with isolated congenital anosmia and 9 age- and g ender-matched normosmic controls. There was a significant difference i n Smell Identification Test scores (P < 0.001) and odor detection thre sholds for phenylethyl alcohol (P < 0.001) and isoamyl acetate (P < 0. 001) between the anosmic and normosmic subjects. Detection thresholds for chloracetyl phenone, a trigeminal stimulant, did not differ betwee n the 2 groups. Olfactory evoked potentials were recorded in response to amyl acetate and air control stimuli presented at volume flow rate of 5 l/min, stimulus duration of 40 ms, and randomized interstimulus i ntervals of 6-30 s. In the control subjects, evoked potentials to amyl acetate were characterized by 4 reproducible components (P1, N1, P2, and N2). In the subjects with congenital anosmia, no reproducible evok ed potential components were identified in response to amyl acetate. N o reproducible evoked potential components were seen in response to th e air control stimulus in either the anosmic or normosmic groups. Thes e data suggest that olfactory evoked potentials provide a specific mea sure of olfactory function. (C) 1997 Elsevier Science Ireland Ltd.