Table 2.

Evaluation of different training strategies on the Eindhoven PPG data set.

Model	Training procedure summary	Cohen’s kappa	Accuracy (%)
ECG-trained model	Traina on Siesta	0.57 ± 0.12	71.88 ± 8.34
PPG-trained model	Trainb on Eindhoven	0.55 ± 0.14	69.82 ± 10.23
Domain retrain	Pre-traina on Siesta + adaptb using Eindhoven	0.62 ± 0.12	75.21 ± 7.82
Decision retrain	Pre-traina on Siesta + adaptb using Eindhoven	0.63 ± 0.12	75.14 ± 8.10
Combined retrain	Pre-traina on Siesta + adaptb using Eindhoven	0.65 ± 0.11	76.36 ± 7.57

^aTraining was done on the entire Siesta ECG data set.

^bDone in 4-fold cross-validation. In each fold 45 participants of the Eindhoven data set were used for training and 15 were left out for validation. Shown results are aggregated over all folds. All cross-validation experiments used the same folds to enable comparison. Results are presented as mean ± standard deviation. Distribution of performance over participants and statistical significance tests are shown in Fig. 5.