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Updated: Sep 20, 2025
Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping
Published on: June 26, 2012
The Role of Scalp EEG Recordings During Cortical Visual Prosthesis Testing
Katarina Stephan1, Philip R Troyk2, Gislin Dagnelie3
1Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA.
Introduction:
This article highlights the value of recording scalp electroencephalogram (EEG) from two individuals with blindness who received intracortical visual stimulators to create artificial vision. Given the known risk of cortical stimulation inducing seizures, we recorded occipital scalp EEG as a safety precaution. Over a 3-year period, over 330 h of EEG data were collected.
Methods:
Twenty-five wireless floating microelectrode arrays (WFMAs), each containing 16 stimulating electrodes, were implanted in the right dorsolateral occipital cortex of the first participant, totaling 400 independently controlled stimulating electrodes. Similarly, 32 WFMAs were implanted in the second participant's cortex, totaling 512 electrodes. Phosphenes were characterized and mapped to align their locations in the visual field to create camera-driven imagery of the visual environment.
Results:
Scalp EEG recordings during intracortical stimulation provided early warning of impending epileptic activity, reducing the risk of stimulation-induced seizures. In two instances, seizures occurred during direct cortical stimulation and were visible in the scalp EEG recordings. Normal electrically evoked potentials (eEPs) were also evident in the EEG records.
Conclusion:
Scalp EEG can be valuable to alert researchers to impending seizures. However, it is not required for conditions in which low levels of stimulation are employed.
Trial Registration:
Clinical Trial Number NCT04634383.
