Accurately recognizing artifacts on electroencephalogram (EEG) is necessary to prevent EEG misinterpretation and epilepsy misdiagnosis. EEG artifacts generated by neurostimulation devices ([Figures 1] and [2]) can be identified based on their unique spatial and frequency properties[1].
Figure 1 Vagus nerve stimulation (VNS) EEG artifact. Scalp EEG: sensitivity 7 μV/mm, LF 1 Hz, HF 70 Hz, notch on; invasive EEG: sensitivity 100 μV, LF 0.53 Hz, HF 600 Hz, notch off. Scalp EEG (top), extended longitudinal bipolar montage (with additional frontotemporal electrodes) showing a burst of low-voltage sharply contoured artifact mostly at the EKG channel but also at the across FT9-FT10 and A1-A2 bipolar channels. Invasive EEG (bottom), bipolar montage showing a burst of low-voltage 20 Hz sharply contoured artifact at the EKG channel. The artifacts’ 20 Hz frequency corresponded to the stimulating frequency in both cases.
Figure 2 Responsive neurostimulation (RNS) and deep brain stimulation (DBS) scalp EEG artifacts - extended longitudinal bipolar montages (with additional frontotemporal electrodes). EEG: sensitivity 7 μV/mm, LF 1 Hz, HF 70 Hz, notch on.RNS (top, 15-second; middle, 5-second view): repetitive 200 Hz stimulation artifact (red rectangles) followed by C3-P3 device detection artifact (blue stars). RNS strip electrodes were in the left posterior temporal topography with generator in the left frontal region. DBS (bottom): continuous, diffuse, electrical interference without evolution.
VNS and RNS artifacts display an electrical interference-like “spiky” morphology with a distribution that is incompatible with a cerebral source and frequencies that mirror stimulation settings. DBS artifact features diffuse electrical interference with a relatively monomorphic appearance, and its frequency can vary depending on intermittent versus continuous neurostimulation - indicated for epilepsy and movement disorders, respectively.
