Olfactory event-related potentials and aging: normative data

Unlike the clinical usages of evoked potentials (e.g. brain stem auditory e voked potentials for the assessment of auditory function), normative data f or the olfactory event-related potential (OERP) have been unavailable. The principal objective was to establish normative data across the human life s pan for OERPs with a given set of parameters. Participants were 140 persons from seven age groups (16-19, 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years of age), with equal numbers of males and females, screened for nasal health and dementia. The odor stimulus was amyl acetate, presented at nasal temperature in a humidified airstream delivered by an air-dilution olfacto meter at a constant flow rate, using a 60-s inter-stimulus interval. OERPs were recorded at Fz, Cz, and Pz electrode sites, amplified and averaged ove r trials. Amplitudes of the N1/P2 and P3 and latencies of the P2 and P3 wer e analyzed. Processing speed decreased at a constant rate over decades for the sensory (P2 latency) as well as cognitive (P3 latency) components. Decl ine in amplitude over decades was also apparent. Normative data will be use ful in research on olfactory function and in clinical assessment of olfacto ry functional status. (C) 2000 Published by Elsevier Science B.V. All right s reserved.