Wrist-Worn Electrodermal Activity as a Novel Neurophysiological Biomarker of Autonomic Symptoms in Spatial Disorientation

Figures

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  Figure 1. Device used to produce a variety of tilt environments with visual stimulation. Publication of these images has been approved by the Aeromedical Laboratory, Japan Air Self-Defense Force. (A) Spatial orientation training device, GYROLAB GL-4000. (B) Inside the cockpit. Images were projected onto a screen in front of the participants.

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  Figure 2. Time course of spatial disorientation training and a representative example of EDA measurement. Participants were exposed to spatial disorientation training, including a visual illusion, vestibular illusion, and a combination of the two for ~30 min. We recorded EDA changes during training. EDA, electrodermal activity.

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  Figure 3. Device used to evaluate EDA. The wrist-worn EDA evaluation device, Q sensor. EDA, electrodermal activity.

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  Figure 4. Evaluation of EDA and subjective autonomic symptoms during spatial disorientation training using the Q sensor and Graybiel criteria, respectively. The maximum amount of change was significantly greater in the ≥3 points group compared with the 0 points group (p < 0.01) and the 1–2 points group (p < 0.05). EDA, electrodermal activity. The error bars represent the mean (S.E.) in all graphs. *p < 0.05, **p < 0.01.

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  Figure 5. Relationship between the maximum amount of EDA change and the total Graybiel score in the ≥3 points group. No significant (p > 0.05) correlation (r = −0.059) was observed between the maximum EDA change and the total Graybiel score.

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  Figure 6. Evaluation of the number of EDA peaks and subjective autonomic symptoms during spatial disorientation training using the Q sensor and Graybiel criteria, respectively. We found no significant differences (p > 0.05) in the number of EDA peaks between the 0, 1–2, and ≥3 points groups. EDA, electrodermal activity. The error bars represent the mean (S.E.) in all graphs.

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  Figure 7. Evaluation of the mean EDA amplitude and subjective autonomic symptoms during spatial disorientation training using the Q sensor and Graybiel criteria, respectively. The mean amplitude was significantly increased in the ≥3 points group compared with the 0 points (p < 0.01) and the 1–2 points groups (p < 0.05). EDA, electrodermal activity. The error bars represent the mean (S.E.) in all graphs. *p < 0.05, **p < 0.01.

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  Figure 8. Evaluation of the AUC of the EDA data and subjective autonomic symptoms during spatial disorientation training using Q sensor and Graybiel criteria, respectively. We found no significant differences (p > 0.05) in the AUC between the 0, 1–2, and ≥3 points groups. AUC, area under the curve. EDA, electrodermal activity. The error bars represent the mean (S.E.) in all graphs.

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  Figure 9. Evaluation of EDA using the Q sensor and subjective autonomic symptoms during spatial disorientation training for each of the seven Graybiel diagnostic categorizations. (A–G) The maximum amount of EDA change was significantly higher in the ≥1 points group compared with the 0 points group for “cold sweating” and “salivation” (p < 0.05, each) (A,B). However, we observed no significant changes between the 0 points group and the ≥1 points group for the other five autonomic symptoms (C–G). The error bars represent the mean (S.E.) in all graphs. *p < 0.05.