Fig 1.
Displayed is a schematic drawing of the custom-built olfactometer, which was used in the study. The flow switch was controlled by a computer directing the air either through a glass bottle with water (between stimuli) or through one of the bottles marked A, B or C for stimulus presentation. The stimuli were therefore presented in a clean–odorless airflow of 2l/min.
Table 1.
Stimulus conditions used in part I.
Fig 2.
AUC in relation to different stimulus conditions.
Displayed are the AUC calculated by ROC, a-d for olfactory and e-h for trigeminal stimulation for the four stimulus conditions. The largest AUC and therefore the highest sensitivity and specificity to distinguish between control and olfactory stimulation in terms of EEG-power change was obtained in condition D. The AUC analysis revealed only a significant AUC for trigeminal stimulation in condition B.
Table 2.
EEG-power in response to olfactory stimulation.
Table 3.
EEG-power change in response to trigeminal stimulation.
Fig 3.
EEG-power change after olfactory, trigeminal and control stimulation (condition D).
Displayed are the Cz EEG-power changes (group average including the 10 participants) after control (a), olfactory (b) and trigeminal (c) stimulation. The dashed black line marks the stimulus onset. An increase in low frequency within the ROI (red square) can be observed in b and c but not in a. The scale displays EEG-power change in percent compared to the pre-stimulus interval.
Fig 4.
Distinguishing between patients and normosmic participants by means of time-frequency analysis.
Displayed are the AUC calculated by ROC analysis to distinguish between normosmic participants and dysosmic (hyposmic/anosmic) patients. The analysis revealed an AUC of 0.78 for the separation of normosmic participants and dysosmic patients. The analysis between normosmic participants and anosmic patients was even greater with an AUC of 0.91.