Neural indicators of sleep loss and sleep propensity in male military trainees: Insights from dry‐electrode EEG—An exploratory study

FIGURE 1. Displays the: (a) dry‐electrode EEG system (DSI‐7, Wearable Sensing, LLC, San Diego CA) and (b) the electrode placement used, with electrodes (F3, F4, C3, C4, Pz, P3, and P4) based upon the International 10–20 system.

FIGURE 2. Difference between baseline (week 1) and “live‐in” (week 2) are displayed for the; 10‐min Psychomotor Vigilance Task (PVT‐10), comparing averaged lapses (panel a), median reaction times (RT) (panel b), and false starts (panel c); Oculography data from the Eye‐Sync device for the radial (panel d), tangential (panel e), and horizontal (panel f) results. The normalized Relative Power Spectrum Density (PSD; Task Related Power [TRP]) values plotted against the frequency bands, comparing the baseline week (week 1) versus the “live‐in” week (week 2) for the Psychomotor Vigilance Task (PVT) protocol (panel g) and EyeSync protocol (panel h). Box and whisker plots show ranges from the minimum to maximum values for each dataset. The interquartile range (IQR) spans from the 25th to the 75th percentile, representing the spread of the middle 50% of the data. Whiskers indicate the overall data range. Error bars represent 1 standard deviation. * denotes p < 0.05.

FIGURE 3. Average log transformed Power Spectrum Density (PSD) (μV2/Hz) values plotted against all frequency bands, comparing the baseline week (week 1) to the “live‐in” week (week 2) for the eyes‐closed protocol, relative to baseline. Within the graph, averages of each participant are presented per week, and are denoted as am or pm accordingly.

FIGURE 4. Difference between baseline (week 1) and “live‐in” (week 2) are displayed for the; Oculography task (Eye‐Sync), displaying the percentage (%) of total task time spent fully awake (panel a) and asleep (panel b); the 10‐min Psychomotor Vigilance Task (PVT‐10), displaying the percentage (%) of total task time spent fully awake (panel c) and asleep (panel d); the 2‐min eyes closed protocol displaying the percentage (%) of total task time spent fully awake (panel e) and asleep (panel f). The percentage (%) of total task time spent in an intermediate (drowsy/transition) stage is displayed for the Oculography task (Eye‐Sync), PVT‐10, and 2‐min eyes closed in panels g, h, and i, respectively. * denotes p < 0.05.

FIGURE 5. The normalized parametric statistic topographical comparison of the baseline week (week 1) and the “live‐in” week (week 2) for the (a) eyes‐closed protocol and (b) Psychomotor Vigilance Task (PVT) protocol. These topographical plots display the normalized Power Spectrum Densities (μV2/Hz) within the theta band (4–7 Hz) for week 1, week 2, and the p value parameter, respectively.