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. 2021 Dec 27;45(3):zsab259. doi: 10.1093/sleep/zsab259

Figure 1.

Figure 1.

Principal Component Analysis for REM sleep without atonia (RSWA) values in PTSD with and without dream enactment and control groups yielded 13 principal components. (A) Scree plot of the 13 principal components showed that principal components #1 and 2 exceeded eigenvalues of 1. (B) Cumulative variance plot demonstrating the eigenvalues and amount of RSWA variance explained for each of the 13 principal components, demonstrating that components 1 and 2 together explained 78% of the variance in RSWA values. (C) Principal Components Plot for the 13 RSWA principal components shows clear separation between the iRBD, PTSD, PTSD+DEB, and control groups. (D) Pearson correlation coefficients for the RSWA principal components 1 and 2 and manually and automatically (RAI) determined RSWA metrics demonstrate that all RSWA metrics (except average leg duration) were highly correlated with principal component 1, while tonic density, RAI, and AASM leg phasic RSWA metrics were correlated with component 2.