Detection rates of chemosensory evoked Potenzials with healthy andanosmic subjects

Abstract

The detection rate of olfactory chemosensory event-related EEG Potentials (oCSERP) and trigeminal chemosensory event-related EEG Potentials (tCSERP) is also dependent on the stimulants and the evaluator of the averaged EEG curves. In 45 subjects with age-appropriate normal olfactory capacity (NP) and 20 anosmics (AN), oCSERP (stimulation by hydrogen sulphide, H2S 6 ppm and phenylethyl alcohol, PEA 30 % v/v,) and tCSERP (irritation with CO2 20-60 % v/v, intensity standardized) were derived by default. Two investigators categorized the averaged EEG curves in: CSERP recognizable, no CSERP recognizable and artefact. Investigator 1 knew whether the subject was a NP or an AN, and which stimulants was used, whereas investigator 2 lacked this information. AN needed higher trigeminal stimulus concentrations but showed same intensity ratings compared to NP. The attention (tracking game) did not deteriorate in the course of test. The detection rate of H2S-CSERP was higher than that of PEA-CSERP. The match of H2S-CSERP detection rates between the two investigators was higher than that of PEA-CSERP and CO2-CSERP. For the standard derivation of oCSERP, stimulation with H2S is usually sufficient. Stimulation with PEA and CO2 as well as a blinded investigator is not necessary.