TABLE 2.
Study of aLL-tVNS effects (linear mixed model).
| Independent variable | Coefficient ± SE | p-value | |
| HR, bpm | Intercept | 61.7 ± 1.6 | – |
| 5-Hz stimulation sequence (ref = control) | −0.3 ± 0.6 | 0.57 | |
| 20-Hz stimulation sequence (ref = control) | −0.2 ± 0.6 | 0.77 | |
| Stimulation phase (ref = baseline phase) | −1.1 ± 0.6 | 0.09 | |
| 5-Hz stim sequence × Stim phase | 0.7 ± 0.9 | 0.42 | |
| 20-Hz stim sequence × Stim phase | 0.9 ± 0.9 | 0.28 | |
| RMSSD, ms | Intercept | 47.7 ± 4.7 | – |
| 5-Hz stimulation sequence (ref = control) | −0.2 ± 2.1 | 0.93 | |
| 20-Hz stimulation sequence (ref = control) | −1.3 ± 2.1 | 0.53 | |
| Stimulation phase (ref = baseline phase) | 0.2 ± 2.1 | 0.91 | |
| 5-Hz stim sequence × Stim phase | 0.7 ± 2.9 | 0.82 | |
| 20-Hz stim sequence × Stim phase | −1.4 ± 2.9 | 0.64 | |
| SDRR, ms | Intercept | 70.5 ± 4.9 | - |
| 5-Hz stimulation sequence (ref = control) | −7.2 ± 3.0 | 0.020 | |
| 20-Hz stimulation sequence (ref = control) | −6.2 ± 3.0 | 0.043 | |
| Stimulation phase (ref = baseline phase) | −3.1 ± 3.0 | 0.31 | |
| 5-Hz stim sequence × Stim phase | 6.7 ± 4.3 | 0.12 | |
| 20-Hz stim sequence × Stim phase | 1.0 ± 4.3 | 0.81 | |
| LF component, | Intercept | 7.41 ± 0.21 | – |
| ms2* | 5-Hz stimulation sequence (ref = control) | −0.33 ± 0.16 | 0.036 |
| 20-Hz stimulation sequence (ref = control) | −0.31 ± 0.16 | 0.048 | |
| Stimulation phase (ref = baseline phase) | −0.11 ± 0.16 | 0.48 | |
| 5-Hz stim sequence × Stim phase | 0.27 ± 0.22 | 0.23 | |
| 20-Hz stim sequence × Stim phase | 0.17 ± 0.22 | 0.44 | |
| HF component, | Intercept | 6.86 ± 0.21 | – |
| ms2* | 5-Hz stimulation sequence (ref = control) | −0.08 ± 0.11 | 0.48 |
| 20-Hz stimulation sequence (ref = control) | −0.25 ± 0.11 | 0.025 | |
| Stimulation phase (ref = baseline phase) | −0.01 ± 0.11 | 0.92 | |
| 5-Hz stim sequence × Stim phase | −0.002 ± 0.153 | 0.99 | |
| 20-Hz stim sequence × Stim phase | −0.09 ± 0.15 | 0.56 | |
| LF/HF ratio, | Intercept | 2.18 ± 0.25 | – |
| % power ratio | 5-Hz stimulation sequence (ref = control) | −0.54 ± 0.23 | 0.021 |
| 20-Hz stimulation sequence (ref = control) | −0.15 ± 0.23 | 0.52 | |
| Stimulation phase (ref = baseline phase) | −0.34 ± 0.23 | 0.14 | |
| 5-Hz stim sequence × Stim phase | 0.76 ± 0.32 | 0.020 | |
| 20-Hz stim sequence × Stim phase | 0.26 ± 0.32 | 0.42 | |
| SBP, mmHg | Intercept | 114.7 ± 2.0 | – |
| 5-Hz stimulation sequence (ref = control) | 1.0 ± 1.1 | 0.39 | |
| 20-Hz stimulation sequence (ref = control) | −0.1 ± 1.1 | 0.93 | |
| Stimulation phase (ref = baseline phase) | 0.2 ± 1.1 | 0.87 | |
| 5-Hz stim sequence × Stim phase | −1.3 ± 1.6 | 0.42 | |
| 20-Hz stim sequence × Stim phase | −0.3 ± 1.6 | 0.86 | |
| DBP, mmHg | Intercept | 58.5 ± 1.7 | – |
| 5-Hz stimulation sequence (ref = control) | 0.5 ± 0.7 | 0.47 | |
| 20-Hz stimulation sequence (ref = control) | 0.3 ± 1.7 | 0.64 | |
| Stimulation phase (ref = baseline phase) | −0.1 ± 0.7 | 0.89 | |
| 5-Hz stim sequence × Stim phase | −0.3 ± 1.0 | 0.75 | |
| 20-Hz stim sequence × Stim phase | 0.2 ± 1.0 | 0.84 | |
| MBP, mmHg | Intercept | 77.2 ± 1.7 | – |
| 5-Hz stimulation sequence (ref = control) | 0.6 ± 0.8 | 0.41 | |
| 20-Hz stimulation sequence (ref = control) | 0.2 ± 0.8 | 0.82 | |
| Stimulation phase (ref = baseline phase) | 0.0 ± 0.8 | 0.99 | |
| 5-Hz stim sequence × Stim phase | −0.6 ± 1.1 | 0.57 | |
| 20-Hz stim sequence × Stim phase | 0.0 ± 1.1 | 0.97 | |
| BF, bursts per | Intercept | 17.6 ± 2.7 | – |
| minute | 5-Hz stimulation sequence (ref = control) | 1.4 ± 1.1 | 0.21 |
| 20-Hz stimulation sequence (ref = control) | −1.5 ± 1.1 | 0.19 | |
| Stimulation phase (ref = baseline phase) | −4.8 ± 1.1 | <0.001 | |
| 5-Hz stim sequence × Stim phase | 0.5 ± 1.6 | 0.75 | |
| 20-Hz stim sequence × Stim phase | 1.3 ± 1.6 | 0.41 | |
| MSNA activity, | Intercept | 3.95 ± 0.20 | – |
| AU/min* | 5-Hz stimulation sequence (ref = control) | 0.12 ± 0.10 | 0.21 |
| 20-Hz stimulation sequence (ref = control) | −0.09 ± 0.10 | 0.34 | |
| Stimulation phase (ref = baseline phase) | −0.13 ± 0.10 | 0.19 | |
| 5-Hz stim sequence × Stim phase | −0.06 ± 0.14 | 0.66 | |
| 20-Hz stim sequence × Stim phase | −0.003 ± 0.139 | 0.99 |
*Models are predicting the log-transformed variable. Significant values at level α = 5% are bolded.