Consistency of Long-Term of Subdural Electrocorticography in Humans

Ewan S. Nurse, Sam E. John, Dean R. Freestone, Thomas J. Oxley, Hoameng Ung, Samuel F. Berkovic, Terence J. O'Brien, Mark J. Cook, David B. Grayden

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16 Citations (Scopus)


Objective: Subdural electrocorticography (ECoG) can provide a robust control signal for a brain-computer interface (BCI). However, the long-term recording properties of ECoG are poorly understood as most ECoG studies in the BCI field have only used signals recorded for less than 28 days. We assessed human ECoG recordings over durations of many months to investigate changes to recording quality that occur with long-term implantation. Methods: We examined changes in signal measurements properties over time from 15 ambulatory humans who had continuous subdural ECoG monitoring for 184 to 766 days. Results: Individual electrodes demonstrated varying changes in frequency power characteristics over time within individual patients and between patients. Group level analyses demonstrated that there were only small changes in effective signal bandwidth and spectral band power across months. High-gamma signals could be recorded throughout the study, though there was a decline in signal power for some electrodes. Conclusion: ECoG-based BCI systems can robustly record high-frequency activity over multiple years, albeit with marked inter-subject variability. Significance: Group level results demonstrated that ECoG is a promising modality for long-term BCI and neural prosthesis applications.

Original languageEnglish
Pages (from-to)344-352
Number of pages9
JournalIEEE Transactions on Biomedical Engineering
Issue number2
Publication statusPublished - Feb 2018
Externally publishedYes


  • Bandwidth
  • Biological system modeling
  • Biomedical engineering
  • biomedical signal processing
  • brain-computer interfaces
  • Decoding
  • Electrodes
  • electroencephalography
  • Hospitals
  • neural prosthesis
  • Prosthetics
  • Telemetry

Cite this

Nurse, E. S., John, S. E., Freestone, D. R., Oxley, T. J., Ung, H., Berkovic, S. F., O'Brien, T. J., Cook, M. J., & Grayden, D. B. (2018). Consistency of Long-Term of Subdural Electrocorticography in Humans. IEEE Transactions on Biomedical Engineering, 65(2), 344-352.