An open-source implementation of Time Selay Stability (TDS) in Python.
This is a copy. Main repository of our group: https://gitlab.gwdg.de/medinfpub/biosignal-processing-group/tdspy
TDSpy
TDS is an established tool for analyzing the interaction between physiological systems in the human organism based on analysis of physiological time series (e.g. ECG, EEG) and has been proposed by Bashan et al. (https://doi.org/10.1038/ncomms1705) in 2012. Since then, it has been used by different groups on different datasets and problems. This led to research groups implementing their own algorithms in different programming languages which poses the risk of differences between implementations and parameters, leading to a lack of reproducibility. Hence, we propose this implementation to work towards reproducible research.
- TDSpy
- feature_extraction: Extract features from biosignals
- sn_getBreathingRate.py
- sn_getEEGBandPower.py
- sn_getEventRate.py
- sn_getQRS.py
- sn_getVariance.py
- signal_processing: Some signal processing tools
- nld_movingAverage.py
- nld_movingMedian.py
- sn_getExtrema.py
- tools
- edf_reader.py: read single EDF file or all EDF files in a directory
- signal_generator.py: generate signals for unit tests
- nld_spectrogram.py: compute short-time fourier transform
- sn_TDS.py: Main function: reads an EDF file and returns TDS value
- sn_getCrossCorrelation.py: computes cross correlation between two signals (used by sn_TDS.py)
- sn_getStability.py: computes stable sequences in lag series (used by sn_TDS.py)
- feature_extraction: Extract features from biosignals
Download available at PyPI
pip install -i TDSpy
import neurokit2 as nk
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
# TDSpy functions
from TDSpy.sn_TDS import sn_TDS_no_feature_extraction as TDS
from TDSpy.feature_extraction.sn_getEEGBandPower import sn_getEEGBandPower
from TDSpy.feature_extraction.sn_getVariance import sn_getVariance
from TDSpy.tools.sn_plotTDS import plot_TDS
from TDSpy.tools.edf_reader import read_all_EDF_channels
# Preparation: Please download these files:
# https://physionet.org/content/ucddb/1.0.0/ucddb002.rec
# https://physionet.org/content/ucddb/1.0.0/ucddb002_stage.txt
def main():
sleep_stage = 0 # wake
dur = 16000 # seconds
# Read EDF
data_dict, data_dict_sampling_rate = read_all_EDF_channels("ucddb002.rec", startrecord=0, endrecord=dur)
# Read sleep stages
stages = pd.read_csv("ucddb002_stage.txt", header=None)
stages = stages.to_numpy()
# Read only single stage
stage_idx = np.where(stages == sleep_stage)[0]
stage_idx = stage_idx[stage_idx < dur/30]
# Process single ECG channel
ecg_signal = nk.ecg_process(data_dict['ECG'], sampling_rate=data_dict_sampling_rate['ECG'], method='neurokit')
hr_signal_resampled = nk.signal_resample(ecg_signal[0]['ECG_Rate'], sampling_rate=data_dict_sampling_rate['ECG'], desired_sampling_rate=1, method="interpolation")
# Process single RESP channel
rsp_rate = nk.rsp_rate(data_dict['Flow'], sampling_rate=8, method="trough")
rsp_signal_resampled = nk.signal_resample(rsp_rate, sampling_rate=data_dict_sampling_rate['Flow'], desired_sampling_rate=1, method="interpolation")
# Process single EMG channel
emg_signal = data_dict['EMG']
emg_var = sn_getVariance(emg_signal, sf=data_dict_sampling_rate['EMG'])
# Process single EOG channel
eog_signal = data_dict['Lefteye']
eog_var = sn_getVariance(eog_signal, sf=data_dict_sampling_rate['Lefteye'])
# Process single EEG channel
eeg_signal = data_dict['C3A2']
fpb, _ = sn_getEEGBandPower(eeg_signal, sf=data_dict_sampling_rate['C3A2'], bandlimits=np.array([[0.5, 4, 8, 12, 16], [3.5, 7.5, 11.5, 15.5, 19.5]]))
# Compute TDS
data_dict = {'HR': hr_signal_resampled, 'Resp': rsp_signal_resampled, 'Chin': emg_var, 'Eye': eog_var, 'Delta': fpb[:,0], 'Theta': fpb[:,1], 'Alpha': fpb[:,2], 'Sigma': fpb[:,3], 'Beta': fpb[:,4]}
tds, combination, stages = TDS(data_dict=data_dict)
# Plot result
nk.signal_plot(pd.DataFrame(data_dict), subplots=True)
plt.show()
# Limit to sleep stage
tds = tds[:,stage_idx[:-1]]
# Matrix plot
plot_TDS(tds, combination)
if __name__ == '__main__':
main()
Sebastian Schmale
Tabea Steinbrinker, tabea.steinbrinker@med.uni-goettingen.de
Dagmar Krefting
Ronny P. Bartsch
Jan W. Kantelhardt
Nicolai Spicher
MIT License
v1.0 - first implementation ready.