Veränderung der elektrischen Hirnaktivität während Vigilanzuntersuchungen im Hinblick auf unterschiedliche motivationale Testbedingungen
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Philipps-Universität Marburg
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Abstract
Introduction and method:
In the Center of Sleep-Medicine at Philipps-Universtiy Marburg daytime
drowsiness and reduction of vigilance are currently under examination by using
both a Marburg developed quadruple-choice reaction time test called VigiMar
and by a pupillografic PST drowsiness test. Both of these vigilance-tests were
carried out on brain electrical correlates of reduction of vigilance and sleepiness
with the help of EEG-tests. Furthermore we tested how differently, high-motivation
was shown in the EEG-test results. Brain electrical activity during the night,
and test results obtained the following day, were also taken into consideration.
From October 2012 to September 2013 we tested 20 student assistants from the
Center of Sleep medicine after having worked nights and with moderate sleep
deprivation (average sleep 2.25 hours), while carrying out VigiMar and PST and
making EEG recordings. Every proband was examined twice: Once under the
test condition “Reward” and once under the test condition “Participation”. Test
condition “Reward” meant that the experimentee could receive a payment up to
400 Euros according to how awake they were. Under test condition “Participation”
there was only a flat sum of 25 Euros offered, irrespective of the results of
the tests.
The relative and absolute power in the frequency bands Delta (0.5-4.0 Hz),
Theta (4.0-8.2 Hz), Alpha (8.0-13 Hz), Beta (13-30 Hz) and Gamma (30-70 Hz)
was calculated from the EEG recordings. In addition, the total power from each
band was determined.
Results:
High Alpha and Theta activity during the VigiMar correlated with slower reaction
times, meaning lower vigilance. High total power, Delta, Beta and Gamma
activity on the other hand was accompanied by shorter reaction times and consequently
higher vigilance. The correlation between high Beta and Gamma-activity
and vigilance was more distinct under conditions of reward than under
conditions of participation.
In the PST the correlation was not as clearly marked but a high total power, as
well as high occipital Beta and Gamma activity, also corresponded in the test
with a smaller pupillary unrest index (PUI), therefore higher vigilance.
The next morning longer reaction times in the VigiMar followed on from high
Beta activity during the night. High Delta activity at night corresponded to better
results in the tests.
For the PST, similar correlations were only observed under conditions of reward:
Increased nightly Beta and Gamma activity correlated with higher PUI,
meaning lower vigilance. On high Delta and Theta activity a lower PUI could be
seen, as well as a higher vigilance.
Discussion:
Plausible results for brain electrical activity during VigiMars could be shown to
agree with the literature using similar test methods. The frequency bands associated
to being awake (Beta and Gamma) corresponded to good test results. Alpha
(relaxed state of being awake) and Theta activity (transition toward sleep)
showed bad test results. A similar correlation with the Beta and Gamma band
shown for the PUI for the first time in this study led in a similar direction, without
being too robust. The correlation between EEG frequency bands during
nightly phases of short sleep and the results of the vigilance test the next morning
are, on the face of it, valid and, as far as we can judge, the first ever recordings
of it. Worse test results following high nightly Beta activity suggests wakefulness.
Better Test results match higher Delta activity being associated with
deep-sleep. Similar results can be shown for the PST, which, however, only
reached statistical significance under the conditions of reward.
The results of the PST being less clear may be due to a shorter testing time (11
versus 90 minutes, with an appropriately smaller data base of the power spectra)
or indicate that VigiMar results correlate better with the EEG indicators of
wakefulness. The results of this research study can be evaluated as a “Proof of
Concept” for the VigiMar and to a lesser degree for the PST, because brain
electrical activity during the tests correlated with the results of the forgoing
short sleep phase in a physiologically expected manner.
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Dates
Created: 2018Issued: 2018-10-22Updated: 2018-10-22
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
DFG-subjects
VigilanzEEGVigiMarBelohnungSchlafentzugMotivationVigilanztesthirnelektrische KorrelatePSTmonetäre Testbedigung
DDC-Numbers
610
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Saßmannshausen, Christina: Veränderung der elektrischen Hirnaktivität während Vigilanzuntersuchungen im Hinblick auf unterschiedliche motivationale Testbedingungen. : Philipps-Universität Marburg 2018-10-22. DOI: https://doi.org/10.17192/z2018.0420.
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This item has been published with the following license: In Copyright