Physiological correlates of cognitive load in laparoscopic surgery

Figures

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  Figure 1. Experience and performance metrics grouped by type of experimental episode (three boxes on the left of each subplot) and by task type, namely Ring Transfer, Ring Transfer Repeated, Threading and Threading Repeated (four boxes on the right). (a) NASA-TLX Average score. (b) NASA-TLX Effort score. (c) Reaction time. (d) Non-response rate. (e) Task completion time. (f) The rates of errors during the Ring Transfer task. (*p < 0.05).

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  Figure 2. Physiological metrics, heart rate (HR) and heart rate variability (HRV) extracted from fNIRS signals and blink rate (BR) from EEG. (a) HR grouped by experimental episode. (b) HR grouped by task type and task-specific repetition. (c) HRV grouped by experimental episode. (d) HRV grouped by task type and task-specific repetition. (e) BR grouped by experimental episode. (f) BR grouped by task type and task-specific repetition. Significant differences were not marked in (a), (c) and (e) in order to avoid clutter. (*p < 0.05).

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  Figure 3. Values of the individual predictor features and targets. Linear fits to the data are shown. The Pearson correlation, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r, and the p-value of linear regression (black line) are shown. The quadratic fit (thick grey curve) and its p-value \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p_{2}$$\end{document}p2 are shown only if \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p_{2} < 0.05$$\end{document}p2<0.05.

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  Figure 4. Predictions of the artificial neural network plotted against the actual values (x-axis) for selected cases. (a) NASA-TLX Average score with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_{CV} = 0.60$$\end{document}RCV=0.60. (b) Completion Time with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_{CV} = 0.84$$\end{document}RCV=0.84. The 45-degree diagonal line corresponds to perfect prediction.

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  Figure 5. Heart rate (a) and heart rate variability (b) extracted from NIRS signals for the experimental episodes, and smoothed by a 10 s moving window. The black curves represent subject average and the shaded regions are the standard deviation of subject variability. For the task episodes, 40 s segments at the beginning and end are shown.

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  Figure 6. Relationships among the heart rate (HR) and heart rate variability (HRV) for Rest and Task. (a) HR and HRV in resting (black) and task performance (red). Black and red dots respectively represent individual subjects in the resting and task blocks. The linear fits to the data are shown as the black and red straight lines. The Pearson correlations are \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r = - 0.32$$\end{document}r=-0.32(resting) and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r = - 0.23$$\end{document}r=-0.23 (task). The insets at the bottom and on the right illustrate the marginal probability distributions, with x-axes matched to the main figure. (b) Resting HR and the task related change in HR relative to resting (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts}…