Table 2.
Sensitivity and effect size of HRV parameters to mental task
| Easy trial Visit 1 | Hard trial Visit 1 | Wilcoxon’s Signed rank | Effect size estimates | Easy trial Visit 2 | Hard trial Visit 2 | Wilcoxon’s Signed rank | Effect size estimates | |
|---|---|---|---|---|---|---|---|---|
| Mean (SD) | Mean (SD) | (p values) | Gamma | Mean (SD) | Mean (SD) | (p values) | Gamma | |
| Mean RR | 0.95 (0.15) | 0.92 (0.15) | <0.0001 | 0.91 | 0.90 (0.10) | 0.88 (0.10) | <0.0001 | 0.89 |
| SDNN | 0.04 (0.03) | 0.03 (0.03) | <0.0001 | 0.48 | 0.03 (0.02) | 0.02 (0.01) | <0.0001 | 0.64 |
| RMSSD | 0.04 (0.04) | 0.03 (0.04) | <0.0001 | 0.80 | 0.03 (0.03) | 0.02 (0.02) | <0.0001 | 0.71 |
| NN50 | 17.23 | 11.05 | 0.002 | 0.81 | 13.37 | 11.94 | 0.46 | 0.89 |
| (30.44) | (23.38) | (24.62) | (21.73) | |||||
| pNN50 | 5.62 (9.67) | 3.72 (8.18) | 0.001 | 0.81 | 4.24 (7.64) | 3.72 (7.10) | 0.19 | 0.83 |
| Lomb LF/HF ratio | 2.76 (2.32) | 2.12 (1.71) | 0.04 | 0.51 | 1.65 (1.22) | 1.58 (1.48) | 0.79 | 0.53 |
| Lomb LF Power (np) | 62.04 (22.73) | 59.08 (20.38) | 0.91 | 0.51 | 53.14 (21.76) | 50.53 (21.39) | 0.17 | 0.58 |
| Lomb HF Power (np) | 37.96 (22.73) | 40.92 (20.38) | 0.91 | 0.51 | 46.86 (21.76) | 49.47 (21.39) | 0.17 | 0.58 |
| Poincare SD1 | 25.82 (31.63) | 21.06 (28.18) | <0.0001 | 0.80 | 18.43 (18.61) | 14.80 (12.04) | <0.0001 | 0.71 |
| Poincare SD2 | 58.19 (42.35) | 48.99 (37.50) | <0.0001 | 0.48 | 43.48 (33.65) | 34.77 (15.91) | <.00001 | 0.63 |
| DFA alpha | 0.94 (0.21) | 0.95 (0.19) | 0.62 | 0.35 | 0.95 (0.17) | 0.94 (0.20) | 0.66 | 0.59 |
| DFA alpha1 | 1.09 (0.34) | 1.07 (0.30) | 0.34 | 0.49 | 1.04 (0.29) | 1.01 (0.32) | 0.25 | 0.58 |
| DFA alpha2 | 0.86 (0.22) | 0.93 (0.24) | 0.04 | 0.40 | 0.90 (0.21) | 0.94 (0.20) | 0.31 | 0.30 |
| Fractal Dimension | 0.90 (0.07) | 0.88 (0.12) | 0.90 | 0.42 | 0.88 (0.15) | 0.86 (0.14) | 0.65 | 0.07 ϕ |
| LLE | 0.23 (0.12) | 0.29 (0.28) | 0.48 | −0.03 ϕ | 0.27 (0.23) | 0.22 (0.12) | 0.44 | −0.18 |
| LZ | 1.29 (0.14) | 1.27 (0.17) | 0.55 | 0.33 | 1.30 (0.13) | 1.3 (0.13) | 0.70 | 0.49 |
| Multiscale Entropy | 4.54 (0.66) | 4.65 (0.71) | 0.23 | 0.33 | 4.47 (0.91) | 4.58 (0.82) | 0.32 | 0.48 |
| Sample Entropy | 1.40 (0.26) | 1.45 (0.26) | 0.25 | 0.40 | 1.43 (0.32) | 1.49 (0.35) | 0.31 | 0.54 |
| Spectral Entropy | 1.89 (0.51) | 1.85 (0.45) | 0.35 | 0.42 | 1.95 (0.47) | 1.78 (0.56) | 0.03 | 0.47 |
| Spectral Kurtosis | 7.60 (5.24) | 8.15 (5.17) | 0.26 | 0.32 | 8.49 (9.11) | 9.99 (9.80) | 0.05 | 0.51 |
| Spectral Skewness | 2.00 (1.10) | 2.09 (1.07) | 0.41 | 0.37 | 2.09 (1.20) | 2.30 (1.40) | 0.18 | 0.50 |
Abbreviations: np- normalized percentage; DFA- detrended fluctuation analysis; LLE-largest Lyapunov Exponent; LZ - Lempel-Ziv complexity measure. Note: All the HRV parameters had significant effect sizes with p ≤ 0.005, except those in bold and marked with ϕ.