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Abstract: The electroencephalogram (EEG) power spectrum changes induced by hypoxia were investigated in relation to mental workload, cognitive processing and performance. EEG recordings were approximated by an autoregressive process. The order and parameters of the appropriate AR model were estimated in a way to fit the measured EEG as closely as possible. ... During the recovery period, the ARSD was also increased, compared with 100% oxygen condition but not statistically significant. ...
Introduction
Since Berger’s 1929 discovery of electrical brain activity in humans, there has been extensive research aimed at linking EEG changes to mental events and behavioural characteristics [3]. ...
From the moment that Berger (1934) described slowing of the EEG in patients breathing in a closed space, celebral hypoxia has been studied in clinical neurophysiology [4]. ... The EEG changes due to hypoxia are generally considered as similar to those of ishaemia.
The power spectrum has been widely used to characterize EEG. Another popular model means to give a parametric description of EEG is through linear autoregressive (AR) modelling [5]. In this paper, distance measures are studied to capture changes in EEG. The goal is to study the power spectrum of EEG measurements using linear autoregressive modelling in hypoxia. The distance measures discussed in this paper assume that normal baseline EEG is available. ... Each subject was trained on the cognitive task for a total time of two hours in 4 sessions held in two consecutive days.
Equipment
The performance-training task was carried out in the Experimental Physiology Laboratory. ... 1 70
The Biologic-Brain Atlas III was used for the EEG recordings, connected with the ECI Electro-Cap Electrode system. ...
Figure 1: Subject during the experiment using the aviation masque.
For the performance tasks, an IBM PC-based flight simulation, the Multiple Attribute Task Battery (MATB) developed by Comstock and Arnegard (1992) at NASA Langley Research Center was used. ... The battery incorporates tasks analogous to activities that aircraft crewmember perform in flight, while providing a high degree of experiment control, performance data on each subtask, and freedom to use non-pilot test subjects. ... When this became red the subject’s task was to respond by pressing the F6 key.
Figure 2: Multiple Attribute Task Battery (MATB)
Procedure
At sea level, subjects performed the 3-minute task as a warm-up. A baseline was recorded to establish each individual’s normal EEG pattern. The task was performed in the three conditions of 100% oxygen, hypoxia (gas mixtures) and recovery with 100% oxygen at different altitude level of 20. ...
During the experimental period, EEG and EOG were monitored via Ag-AgCl electrodes. ... During recording periods qualified personnel monitored the signals on screen to ensure that any controllable artefacts from subject movements or eye blinks could be eliminated.
Approximate Word count = 2201
Approximate Pages = 8.8
(250 words per page double spaced)
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