Fig. 7: EEG markers of high cognitive states computed before stimulus presentation predict responsiveness to stimuli in each nonlucid sleep stage.
a,b, We fed a random forest classifier with our nine EEG markers and trained it to classify R trials versus NR ones using a tenfold cross-validation method. We conducted this analysis considering all responses (in blue), then separately for both correct (in green) and incorrect responses (in red). A confusion matrix for correct REM sleep trials in nonlucid naps of participants with narcolepsy is shown in a, with a description of the balanced accuracy measure that we computed to take unbalanced datasets into account. The confusion matrix for each stage and group can be found in Supplementary Table 9. Balanced accuracy scores are plotted in b for different sleep stages, in function of response accuracy, both for participants with narcolepsy (wake, N1, N2, REM sleep; left) and without narcolepsy (N2, right), with the corresponding statistical significance against chance level computed with a 500 permutations test (all trials: all NP P values = 0.002, HP P value = 0.006; correct trials: all P values = 0.002; incorrect trials: wake P = 0.002, N1 P = 0.04. Note that 0.002 is the smallest P value obtainable via 500 permutations). Data are presented as mean values ± 95% confidence intervals. n represents a number of datapoints in all (correct + incorrect) trials, taken from 22 NP in wake, from 24 NP in N1, from 23 NP in N2, from 15 NP in REM and from 20 HP. TP, responsive trials classified as responsive; TN, nonresponsive trials classified as nonresponsive; FP, false positives (NR trials classified as responsive). FN, false negatives (R trials classified as nonresponsive).
