In this study, it was investigated whether stress changes the DC potentials
as measured by a classical EEG setup. We used the final oral examination
of the Psychology Master’s degree programme of Vienna University as the
stress situation. All 20 participants were in their final year and had
to pass that examination. Half of the participants received their first
testing one month before (a) and the other testing one or two days before
(b) their examination. The other half had their first testing one or two
days before (b) and passed the other about one month after (c) their examination
date. The test session comprised several standardized tasks such as the
50/50 paradigm, the arrow task, and the CNV paradigm. Always the second
test session of each of these two groups (either b or c) repeated these
three tasks and added a vigilance task. DC potential changes were recorded
from prefrontal (FP1, FP2), frontal (F3, F4), central (C3, C4) and parietal
(P3, P4) locations. At the first occurrence of the 50/50 paradigm, the
left frontal DC potentials negativated significantly in the stress condition.
Also the participants showed a higher performance in the stress situation.
When the 50/50 paradigm was repeated in the extended test situations, no
conclusive results could be found. The results at the arrow task were similar:
In its first occurrence, stress negativated the left frontal potentials,
whereas in the repetition no clear difference could be observed. At the
CNV paradigm, there were significant potential differences between the
hemispheres and between the stress situations. In the stress condition,
the left hemisphere depicted more negative potentials than at the control
condition. In addition to that, the potentials developed differently over
time. The results were present in both repetitions of that task, however,
the effects were weaker in its second occurrence. The DC potentials at
the vigilance task were significantly more negative in the stress situations
compared to their control conditions. In this task, stress did not change
the performance of the participants. However, participants report to feel
more frustrated and anxious in the stressful situation. To summarize, participants
under influence of stress showed more negative DC shifts, especially in
the left hemispheric frontal area. Left frontal negativation is usually
connotated with a decreased subjective feeling of comfort.