Interindividual differences in attentional vulnerability moderate cognitive performance during sleep restriction and subsequent recovery in healthy young men

Figures

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  Figure 1. Psychomotor vigilance task (PVT) lapses by vulnerability per participant across sleep restriction (change from baseline). PVT lapses are reaction times ≥ 500 ms. “Less vulnerable level” estimates were obtained by re-centering attentional vulnerability (i.e., difference in mean lapses on last sleep restriction day relative to the last baseline day for each participant) at 1 standard deviation (SD) below the mean. “More vulnerable level” estimates were obtained by re-centering attentional vulnerability at 1 SD above the mean (N = 15 in all analyses; refer to Statistical Analyses). See Fig. 6 for vulnerability level per participant. Change from baseline (BL) values are plotted; horizontal dotted line indicates the baseline reference level (where change is 0). Comparisons to the BL reference point (the day succeeding the third BL night) during sleep restriction (SR) and recovery (REC) day separated by vulnerability level: *p < .05, **p < .01, ***p < .001, two-tailed. Comparisons to baseline not completed at “less vulnerable level” due to lack of significant trajectory (see Table 1, “by vulnerability” column). Performance at the mean of attentional vulnerability is represented by the…

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  Figure 2. Working memory, visuospatial processing, and processing speed performance across sleep restriction (change from baseline). (a) Visual Object Learning Task (VOLT)40 hits are number of true positives (indicating “definitely yes” or “probably yes” in the recall phase when the image had been presented during the learning phase). (b) VOLT confidence in misses is calculated as the number of “definitely no” misses divided by the total number of misses (“definitely no”+ “probably no”), multiplied by 100. (c) Line Orientation Task (LOT)48 correct responses are the number of target lines (out of 24) correctly rotated to be parallel to the sample line. (d) LOT mean rotation error is the average rotation error from the correct line orientation (with 0 indicating a correct response, the target line exactly parallel to the sample line) for all 24 lines. (e) Digit Symbol Substitution Task (DSST)49 throughput is the number of correct responses/minute per test. (f) DSST median reaction time (RT) correct is the median RT for all correct responses per test (ms). Change from baseline (BL) values are plotted; horizontal dotted line indicates the baseline reference level (where change is 0).…

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  Figure 3. Working memory and visuospatial processing performance by vulnerability level per participant across sleep restriction (change from baseline). (a) Fractal 2-Back (F2B)39 sensitivity is calculated as 100 * (true positives/(true positives + false negatives)). False negatives occur when a participant has been presented with an image previously but fails to tap the screen. (b) F2B median reaction time (RT) for hits (ms). (c) Number of excess clicks for correct responses on the Line Orientation Task (LOT)48. (d) LOT median RT correct is the median RT for all correct responses per test (s). “Less vulnerable level” estimates were obtained by re-centering attentional vulnerability (i.e., difference in mean psychomotor vigilance task lapses on last sleep restriction day relative to the last baseline day for each participant) at 1 standard deviation (SD) below the mean. “More vulnerable level” estimates were obtained by re-centering attentional vulnerability at 1 SD above the mean (N = 15 in all analyses; refer to Statistical Analyses). See Fig. 6 for vulnerability level per participant. Change from baseline (BL) values are plotted; horizontal dotted line indicates the baseline reference…

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  Figure 4. Depiction of 11-Day (10-Night) Inpatient Study Protocol. Black bars represent time in bed (TIB) in dark conditions; white bars represent supervised wake. The first three sleep periods were 10-h TIB baseline (BL) from 22:00 to 08:00. Following BL, participants had 5-h TIB sleep restriction (SR) for 5 nights with TIB from 00:30 to 05:30. Afterward, participants had two 10-h TIB recovery (REC) nights, again from 22:00 to 08:00. All sleep periods were centered at 03:00 to minimize circadian misalignment (white dotted line). Approximately every two hours during wake, participants completed the 20-min cognitive battery (gray dots) including the 10-min psychomotor vigilance task (PVT).

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  Figure 5. Depiction of The Cognitive Tasks During the Inpatient Study. (A) During the learning phase of the Visual Object Learning Task (VOLT)40 of working memory, participants are presented with ten objects displayed for five seconds each. During the succeeding recall phase of the VOLT, participants are presented with ten novel objects and ten seen objects and indicate whether they had seen the object. Correct responses are indicating “probably yes” or “definitely yes” when the object had been presented (hits), or indicating “probably no” or “definitely no” when the object had not been presented (correct rejections). (B) In the Fractal 2-Back (F2B)39 of working memory, participants are presented with sequential images for 1.7 s each and asked to tap the screen when an image appears that has appeared two images prior. Correct responses are tapping the screen when an image had been presented previously (hits, which increase sensitivity), or withholding a response when an image had not been presented previously (correct rejections, which increase specificity). (C) In the Line Orientation Task (LOT)48 of visuospatial processing, participants are asked to tap the bottom arrows to incrementally…

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  Figure 6. Computation of Attentional Vulnerability Per Participant. The mean difference in the number of lapses per 10-min psychomotor vigilance task (PVT) during the last sleep restriction day (SR5) versus the last baseline day (BL) are depicted in ascending order, indicating the vulnerability per participant. Vulnerability per participant was used as a continuous moderator in analyses of cognitive variables.