When is electrical cortical stimulation more likely to produce afterdischarges?

Hyang Woon Lee, W. R.S. Webber, Nathan Crone, Diana L. Miglioretti, Ronald P. Lesser

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27 Scopus citations


Objective: To study when afterdischarges (ADs) are more likely to occur during cortical stimulation. Methods: We examined 6250 electrical stimulation trials in 13 patients with subdural electrodes, studying whether AD occurrence during a trial was influenced by electrode pair stimulated or AD occurrence during the previous trial. In total 545 electrodes were stimulated, 119 frontal (pre-perirolandic), 289 perirolandic, 36 parietal (post-perirolandic), 95 temporal, and 6 occipital. Results: When the same electrode pair was stimulated as the prior trial, 19% produced ADs compared to 5% of trials when a different electrodes pair was stimulated (p < 0.0001). When trials showed ADs, and the next trial stimulated the same electrode pair, ADs occurred in 46% of cases, compared to 13% of trials following trials without ADs (p < 0.0001). AD probability decreased with increased inter-trial interval length only when the prior trial was at the same electrode pair and had produced an AD (p = 0.001). AD probability increased with stimulation duration, whether the trial followed a trial with (p < 0.001) or without (p < 0.0001) an AD. Conclusions: ADs were more likely to occur when an electrode pair showed ADs and was stimulated again, especially when stimulating after short inter-trial intervals or for longer duration. Significance: When ADs occur, waiting about a minute before resuming stimulation might lessen the likelihood of AD recurrence.

Original languageEnglish
Pages (from-to)14-20
Number of pages7
JournalClinical Neurophysiology
Issue number1
StatePublished - Jan 2010

Bibliographical note

Funding Information:
Hyang Woon Lee was supported by the Korea Science and Engineering Foundation (KOSEF) Grant funded by the Korean Government (MOST) (No. R01-2007-000-11080-0 ) and the Korea Research Foundation Grant funded by the Korean Government (MEST) ( KRF-2009-007-2164 ). Nathan E. Crone was supported by Grant NINDS R01NS40596 from the National Institutes of Health . We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. None of the authors has any conflict of interest to disclose.


  • Afterdischarges
  • Cortical stimulation
  • Epilepsy surgery
  • Functional mapping
  • Inter-trial interval


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