The experimental design has been previously used by our
group.36–41 One session consisted of two trials of 20 min each.
At the beginning and end of each trial, behavioural parameters
were assessed by visual analogue scales (VAS). Autonomic
parameters were recorded continuously during each trial. In the
first trial, which served as a control for influences of the experimental
set-up, the placebo substance was administered to all
subjects. In the second trial the placebo was again administered
to the control group, whereas in the experimental group the
appropriate fragrance was administered.