Data were split into a training dataset and testing dataset
PD
The entire dataset included 164 recordings (PD: 84, ET: 80), of which 80% of the recordings (PD: 67, ET: 64) were used for training, whereas the remaining 20% (ET: 13, PD: 20) were used for independent testing. In the training dataset, we ensured that the age, sex, and height between the PD and ET groups were matched. Leave-one-out cross-validation (LOOCV) was performed to fine-tune the model parameters in the training data. The final model was selected among different candidate models based on model LOOCV performance. Independent testing was used to provide an unbiased evaluation of the final model (Fig. Model training and independent test data evaluation