**10. Stress quantification using mDFA**

Lobster EKGs are presented in Figure 24. The data presented in Figure 24A were recorded when specimens were in a non-stressful state when no human was present in the room. The data presented in Figure 24B were recorded during micro-dialysis blood sampling. The heartbeat interval time series obtained from the highlighted section is shown in Figure 25 for 578 beats. Under the no-stress condition, the lobster exhibited a dynamically changing pattern (Figure 25, red line) indicated by numerous spikes in the data. This is evidence that the heart received an inhibitory command from CI. In contrast, the lobster under the MD stress condition did not exhibit such a dynamic pattern (Figure 25, black line). Inhibitory neural control was not evident, suggesting the stressed state is a state dominated by acceleratory neurons.

The scaling nature is expressed as a slope in the mDFA graph. The scaling nature of the no stress and MD stress states are presented in Figure 26. mDFA computation revealed a signif‐ icant difference between the two states. Stress (caused by an approaching human) clearly decreased the slope (Figure 26 and 27). SI values of approximately 0.55 and 1.0 were obtained when a human did or did not approach the lobsters, respectively (Figure 27). These animal model experiments suggested that it may be possible to quantify human stress using the mDFA technique.

**Figure 24.** EKGs measured under no-stress (A) and MD-stress (B) conditions (these data were collected from the same lobster used in Figures 3 and 7).

**Figure 25.** Interval time series obtained from data presented in Figure 24.

**10. Stress quantification using mDFA**

technique.

374 Advances in Bioengineering

lobster used in Figures 3 and 7).

Lobster EKGs are presented in Figure 24. The data presented in Figure 24A were recorded when specimens were in a non-stressful state when no human was present in the room. The data presented in Figure 24B were recorded during micro-dialysis blood sampling. The heartbeat interval time series obtained from the highlighted section is shown in Figure 25 for 578 beats. Under the no-stress condition, the lobster exhibited a dynamically changing pattern (Figure 25, red line) indicated by numerous spikes in the data. This is evidence that the heart received an inhibitory command from CI. In contrast, the lobster under the MD stress condition did not exhibit such a dynamic pattern (Figure 25, black line). Inhibitory neural control was not evident, suggesting the stressed state is a state dominated by acceleratory neurons.

The scaling nature is expressed as a slope in the mDFA graph. The scaling nature of the no stress and MD stress states are presented in Figure 26. mDFA computation revealed a signif‐ icant difference between the two states. Stress (caused by an approaching human) clearly decreased the slope (Figure 26 and 27). SI values of approximately 0.55 and 1.0 were obtained when a human did or did not approach the lobsters, respectively (Figure 27). These animal model experiments suggested that it may be possible to quantify human stress using the mDFA

**Figure 24.** EKGs measured under no-stress (A) and MD-stress (B) conditions (these data were collected from the same

**Figure 26.** Results of mDFA (program A). Slope and SI for no-stress and MD stress conditions.

**Figure 27.** Scaling exponent (SI) computed from EKGs under no stress and MD stress conditions. SI computations from various time periods are shown by bars (a, b, c,---ac, ad).
