[Eeglablist] Stimulation artifact in EEG recording

[Emily McNicol (PGR)]

Hello,

I am trying to record EEG during simultaneous surface electrical spinal cord stimulation. However, I am getting unexpected artifact in the signal at around 8Hz, 20Hz and 37Hz during stimulation trials.

Stimulation is delivered at a frequency of 30Hz and 10kHz carrier frequency with a DS8R biphasic constant current stimulator. The stimulation cables have been shielded.

I am using active EEG electrodes with ground and reference electrodes on AFz and right earlobe, respectively. EEG was internally filtered with a band-pass filter at 0.01-100Hz and notch filter at 50Hz. A 3rd order Butterworth band-pass filter with cutoff frequencies of 3Hz and 50Hz was used online and a 5th order Butterworth filter with cutoff frequencies of 3Hz and 50Hz was applied offline.

I have attached below PSD plots of C3 and C4 channels during 60s eyes closed with and without stimulation. The peak at ~28Hz is the expected stimulation artifact, any idea where the other peaks come from and how to prevent this artifact during stimulation?

[cid:image002.png at 01DAC644.32A152C0]

























Many Thanks,
Emily

E L McNicol (she/her)
PhD Researcher | Biomedical Engineering Department
James Watt School of Engineering | University of Glasgow
James Watt South Building | G12 8QQ | Glasgow | Scotland
Contact # +44 (0)753 551 0713
[https://urldefense.com/v3/__http://www.gla.ac.uk/t4/visualidentity/files/downloads/colleges/College*20of*20Science*20&*20Engineering/BMP/CollEng_colour.bmp__;JSUlJQ!!Mih3wA!HvF3mZzwoD1C6X4RMjWaN3EF0OU3BmVq9jVHQwcDUpo_fmD2g1Dl1h9npBcRLMhP-y2W7xAtm-LD_f_Xog3eAqOaf0Zg4fMMApkZ$ ]