Abstract
High-density surface electromyography (HD-sEMG) is a recent technique that overcomes the limitations of monopolar and bipolar sEMG recordings and enables the collection of physiological and topographical informations concerning muscle activation. However, HD-sEMG channels are usually contaminated by noise in an heterogeneous manner. The sources of noise are mainly power line interference (PLI), white Gaussian noise (WGN) and motion artifacts (MA). The spectral components of these disruptive signals overlap with the sEMG spectrum which makes classical filtering techniques non effective, especially during low contraction level recordings. In this study, we propose to denoise HD-sEMG recordings at 20 % of the maximum voluntary contraction by using a second-order blind source separation technique, named canonical component analysis (CCA). For this purpose, a specific and automatic canonical component selection, using noise ratio thresholding, and a channel selection procedure for the selective version (sCCA) are proposed. Results obtained from the application of the proposed methods (CCA and sCCA) on realistic simulated data demonstrated the ability of the proposed approach to retrieve the original HD-sEMG signals, by suppressing the PLI and WGN components, with high accuracy (for five different simulated noise dispersions using the same anatomy). Afterward, the proposed algorithms are employed to denoise experimental HD-sEMG signals from five healthy subjects during biceps brachii contractions following an isometric protocol. Obtained results showed that PLI and WGN components could be successfully removed, which enhances considerably the SNR of the channels with low SNR and thereby increases the mean SNR value among the grid. Moreover, the MA component is often isolated on specific estimated sources but requires additional signal processing for a total removal. In addition, comparative study with independent component analysis, CCA-wavelet and CCA-empirical mode decomposition (EMD) proved a higher efficiency of the presented method over existing denoising techniques and demonstrated pointless a second filtering stage for denoising HD-sEMG recordings at this contraction level.
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References
Agante PM, de Sa J (1999) ECG noise filtering using wavelets with soft-thresholding methods. Comput Cardiol 1999:353–358
Al Harrach M, Boudaoud S, Gamet D, Grosset J, Marin F (2014) Evaluation of hd-semg probability density function deformations in ramp exercise. In: Engineering in medicine and biology society (EMBC), 2014 36th annual international conference of the IEEE, pp 2209–2212. IEEE
Allouch S, Al Harrach M, Boudaoud S, Laforet J, Ayachi F, Younes R (2013) Muscle force estimation using data fusion from high-density semg grid. In: 2013 2nd International conference on advances in biomedical engineering (ICABME), pp 195–198. IEEE
Aschero G, Gizdulich P (2010) Denoising of surface EMG with a modified wiener filtering approach. J Electromyogr Kinesiol 20:366–373
Ayachi F, Boudaoud S, Marque C (2014) Evaluation of muscle force classification using shape analysis of the sEMG probability density function: a simulation study. Med Biol Eng Comput 52(8):673–684
Baratta R, Solomonow M, Zhou B-H, Zhu M (1998) Methods to reduce the variability of EMG power spectrum estimates. J Electromyogr Kinesiol 8(5):279–285
Clancy EA, Morin EL, Merletti R (2002) Sampling, noise-reduction and amplitude estimation issues in surface electromyography. J Electromyogr Kinesiol 12:1–16
De Clercq W, Vergult A, Vanrumste B, Van Paesschen W, Van Huffel S (2006) Canonical correlation analysis applied to remove muscle artifacts from the electroencephalogram. IEEE Trans Biomed Eng 53:2583–2587
Euljoon P, Meek S (1995) Adaptive filtering of the electromyographic signal for prosthetic control and force estimation. IEEE Trans Biomed Eng 42:1048–1052
Farina D, Merletti R (2001) A novel approach for precise simulation of the emg signal detected by surface electrodes. IEEE Trans Biomed Eng 48:637–646
Glaser V, Holobar A, Zazula D (2013) Real-time motor unit identification from high-density surface EMG. IEEE Trans Neural Syst Rehabil Eng 21:949–958
Hassan M, Boudaoud S, Terrien J, Karlsson B, Marque C (2011) Combination of canonical correlation analysis and empirical mode decomposition applied to denoising the labor electrohysterogram. IEEE Trans Biomed Eng 58:2441–2447
Hermens HJ, Freriks B, Merletti R, Stegeman D, Blok J, Rau G, Disselhorst-Klug C, Hägg G (1999) European recommendations for surface electromyography. Roessingh Res Dev 8(2):13–54
Kleine BU, van Dijk JP, Lapatki BG, Zwarts MJ, Stegeman DF (2007) Using two-dimensional spatial information in decomposition of surface EMG signals. J Electromyogr Kinesiol 17:535–548
De Luca CJ, Contessa P (2012) Hierarchical control of motor units in voluntary contractions. J Neurophysiol 107(1):178–195
Mello RGT, Oliveira LF, Nadal J (2006) Emg signal filtering based on empirical mode decomposition. Biomed Signal Process Control 1:44–55
Mello RGT, Oliveira LF, Nadal J (2007) Digital butterworth filter for subtracting noise from low magnitude surface electromyogram. Comput Methods Prog Biomed 87:28–35
Murphy SA, Berrios R, Nelson PA, Negro F, Farina D, Schmit B, Hyngstrom A (2015) Impaired regulation post-stroke of motor unit firing behavior during volitional relaxation of knee extensor torque assessed using high density surface emg decomposition. In: Engineering in medicine and biology society (EMBC), 2015 37th annual international conference of the IEEE, pp 4606–4609. IEEE
Rojas-Martinez M, Mananas MA, Alonso JF (2012) High-density surface EMG maps from upper-arm and forearm muscles. J NeuroEng Rehabil 9:85
Safieddine D, Kachenoura A, Albera L, Birot G, Wendling F, Senhadji L, Merlet I (2011) ICA vs CCA for the denoising of interictal epileptic signals: a study of performance based on source localization. IRBM 32(5):298–301
Stegeman DF, K Bert U, L Bernd G, VD Johannes P (2012) High-density surface EMG: techniques and applications at a motor unit level. Biocybern Biomed Eng 32(3):3–27
Sweeney K, McLoone S, Ward T (2013) The use of ensemble empirical mode decomposition with canonical correlation analysis as a novel artifact removal technique. IEEE Trans Biomed Eng 60:97–105
van Dijk JP, Blok JH, Lapatki BG, van Schaik IN, Zwarts MJ, Stegeman DF (2008) Motor unit number estimation using high-density surface electromyography. Clin Neurophysiol 119(1):33–42
Vergult A, De Clercq W, Palmini A, Vanrumste B, Dupont P, Van Huffel S, Van Paesschen W (2007) Improving the interpretation of ictal scalp EEG: BSS-CCA algorithm for muscle artifact removal. Epilepsia 48:950–958
Yavuz UŞ, Negro F, Sebik O, Holobar A, Frömmel C, Türker KS, Farina D (2015) Estimating reflex responses in large populations of motor units by decomposition of the high-density surface electromyogram. J Physiol 593(19):4305–4318
Zhang X, Zhou P (2013) Filtering of surface EMG using ensemble empirical mode decomposition. Med Eng Phys 35:537–542
Zhou P, Lowery M, Dewald JA, Kuiken T (2005) Towards improved myoelectric prosthesis control: high density surface EMG recording after targeted muscle reinnervation. IEEE Eng Med Biol Soc 4:4064–4067
Zwarts MJ, Stegeman DF (2003) Multichannel surface EMG: basic aspects and clinical utility. Muscle Nerve 28:1–17
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This work was carried out and funded in the framework of the Labex MS2T. It was supported by the French Government, through the program “Investments for the future” managed by the National Agency for Research (Reference ANR-11-IDEX-0004-02).
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Al Harrach, M., Boudaoud, S., Hassan, M. et al. Denoising of HD-sEMG signals using canonical correlation analysis. Med Biol Eng Comput 55, 375–388 (2017). https://doi.org/10.1007/s11517-016-1521-x
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DOI: https://doi.org/10.1007/s11517-016-1521-x