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Table 1. Sample description
  Group waitlist (n = 13) Group only intervention (n = 14)
  Mean ± SD Range Mean ± SD Range
Age 25.3 ± 7.0 18-37 22.6 ± 2.8 19-27
BMI in kg/m2 22.9 ± 4.5 18.3-32.2 22.9 ± 3.6 18.4-29.4
Gender 12f, 1m 14f
Active menstrual cycle 11 yes, 2 no 14 yes
HC usage 36.4% 42.9%
PAF sum 54.7 ± 13.4 23-70 57.4 ± 20.2 19-93
BDI-II sum 12.9 ± 7.2 0-27 13.4 ± 8.0 2-30
Inclusion criterium 4 BDI, 4 PAF, 5 both 4 BDI, 4 PAF, 6 both
DASS sum 34.1 ± 7,1 27-54 40.5 ± 8.3 25-50
RMSSD in ms 37.0 ± 10.9 19.6-51.5 41.9 ± 30.1 18.7-128.9
ANT-R Executive in ms 148.1 ± 56.8 76.7-291.3 129.2 ± 39.1 80.8-194.9
ANT-R Orienting in ms 85.0 ± 37.3 36.3-149.6 120.6 ± 35.1 46.7-183.8
Note. The DASS, RMSSD, and ANT-R values were obtained during the first laboratory session of each participant. All other values were assessed during the screening. SD – standard deviation; BMI – body-mass-index; HC – hormonal contraceptives; PAF – premenstrual assessment form; BDI-II – Becks Depression Inventory; DASS – depression anxiety stress scales; RMSSD – root mean square of successive differences; ANT-R – revised attention network test.
 
Table 2. Results of a linear mixed model predicting premenstrual symptoms
  value PAF20 item
Predictors Estimates CI p
(Intercept) 2.92 2.44 – 3.40 <0.001
group [W] -0.28 -0.50 – -0.07 0.010
time -0.30 -0.54 – -0.07 0.012
scale [psy] 1.08 0.61 – 1.56 <0.001
group [W] * time 0.40 0.03 – 0.78 0.034
(group [I] * time) * scale [psy] -0.36 -0.65 – -0.06 0.017
(group [W] * time )* scale [psy] 0.13 -0.26 – 0.51 0.520
Random Effects
σ2 1.40
τ00 participant 0.58
τ00 item 0.24
ICC 0.37
participant 24
item 20
Observations 1300
Marginal R2 / Conditional R2 0.116 / 0.442
Note. The random effect structure includes participant intercepts and item intercepts. PAF20 – premenstrual assessment form short version; group – treatment (biofeedback vs. waitlist); W – waitlist; I – intervention (biofeedback); psy – psychological symptoms.
 
Table 3. Post-Hoc Tukey effects of time*treatment*scale interaction term predicting premenstrual symptoms
  Scale Diff p
Waitlist Physio 0.06 .54
Psych 0.14 .11
Intervention Physio -0.19 .012
Psych -0.42 <.0001
Note. Diff – standardized pre-post treatment difference; psych – psychological symptoms; physio – physiological symptoms.
 
Table 4. Results of a linear mixed model predicting depressive symptoms
  value BDI item
Predictors Estimates CI p
(Intercept) 1.69 0.54 – 0.83 <0.001
group [W] -0.09 -0.18 – 0.00 0.054
time -0.17 -0.24 – -0.10 <0.001
group [W] * time 0.21 0.09 – 0.33 0.001
Random Effects
σ2 0.34
τ00 participant 0.10
τ00 item 0.03
ICC 0.27
participant 27
item 21
Observations 1617
Marginal R2 / Conditional R2 0.010 / 0.281
Note. The random effect structure includes participant intercepts and item intercepts. BDI – Beck’s Depression Inventory II; group – treatment (biofeedback vs. waitlist); W – waitlist.
 
Table 5. Results of a linear mixed model predicting stress/anxiety symptoms
  value DASS item
Predictors Estimates CI p
(Intercept) 1.12 0.64 – 1.60 <0.001
time -0.14 -0.22 – -0.07 <0.001
group [W] -0.11 -0.20 – -0.01 0.023
scale [D] 0.11 -0.19 – 0.40 0.466
scale [S] 0.44 0.15 – 0.74 0.003
rmssd 0.14 0.03 – 0.26 0.015
time * group [W] 0.21 0.09 – 0.34 0.001
Random Effects
σ2 0.35
τ00 participant 0.14
τ00 item 0.07
ICC 0.39
participant 27
item 21
Observations 1617
Marginal R2 / Conditional R2 0.074 / 0.432
Note. The random effect structure includes participant intercepts and item intercepts. DASS – Depression Anxiety and Stress Scale; group – treatment (biofeedback vs. waitlist); W – waitlist; D – depression scale; S – stress scale; RMSSD – root mean square of successive differences.
 
Table 6. Results of a linear mixed model predicting vagally mediated heart rate variability
  log(RMSSD in ms)
Predictors Estimates CI p
(Intercept) 3.53 3.32 – 3.75 <0.001
group [W] 0.07 -0.15 – 0.29 0.546
time 0.06 -0.12 – 0.23 0.509
group [W] * time -0.13 -0.42 – 0.16 0.381
Random Effects
σ2 0.08
τ00 participant 0.21
ICC 0.71
participant 25
Observations 71
Marginal R2 / Conditional R2 0.003 / 0.711
Note. The random effect structure includes participant intercepts. RMSSD – root mean square of successive differences; group – treatment (biofeedback vs. waitlist); W – waitlist.
 
Table 7. Results of a linear mixed model predicting attentional control
  Reaction time
Predictors Estimates CI p
(Intercept) 600.31 574.20 – 626.41 <0.001
time -37.63 -49.22 – -26.05 <0.001
group [W] 39.00 31.02 – 46.99 <0.001
flanker [incongruent] 130.14 123.20 – 137.08 <0.001
cue [valid] -98.44 -106.51 – -90.37 <0.001
time × group [I] × cue [invalid] 45.56 28.15 – 62.97 <0.001
time × group [W] ×cue [invalid] -0.22 -16.33 – 15.89 0.978
time × group [I] × cue [valid] 41.09 27.57 – 54.61 <0.001
time × group [I] × flanker [incongruent] -26.57 -37.90 – -15.25 <0.001
time × group [W] × flanker [incongruent] -9.44 -23.31 – 4.43 0.182
Random Effects
σ2 11369.21
τ00 participant 4325.41
ICC 0.28
participant 27
Observations 7040
Marginal R2 / Conditional R2 0.267 / 0.469
Note. The model predicts trial-based prediction times of the revised attention network test. The random effect structure includes participant intercepts. Group – treatment (biofeedback vs. waitlist); W – waitlist; I – intervention (biofeedback).