OLFACTORY EVENT-RELATED POTENTIALS IN NORMAL HUMAN-SUBJECTS - EFFECTSOF AGE AND GENDER

Behavioral and electrophysiological testing of olfactory function was performed in 33 normal human male and female subjects, 18-83 years of age. Acuity for odor identification and odor detection was verified by standard psychophysical tests. For evoked potential testing, a consta nt flow olfactometer provided odorant stimuli (amyl acetate) or air co ntrol stimuli that were presented to the right nostril by a nasal cann ula at a flow rate of 51/min, duration of 40 msec and random interstim ulus intervals of 6-30 sec. The behavioral tests revealed no significa nt difference between males and females, whereas increasing age was as sociated with a decline in performance on the odor identification test . No reproducible evoked potentials were recorded in response to the a ir control stimulus. Potentials to the odorant stimulus consisted of 4 components named P1, N1, P2 and N2. A significant correlation was fou nd between P2 latency and odor identification test scores, suggesting a relationship between the generation of the P2 component and olfactor y processing. P2 peak latency increased significantly with age at 2.5 msec/year. An age-related decline in N1-P2 interpeak amplitude was see n in male subjects. Topographic differences were seen in the P2 peak a mplitude and the N1-P2 and P2-N2 interpeak amplitudes such that their amplitudes were greatest at Cz and Pz. On average, N1-P2 interpeak amp litudes were larger in the female subjects than in the male subjects, possibly revealing a hormonal influence on the olfactory event-related potential.