Afterdischarges during cortical stimulation at different frequencies and intensities.

Purpose: The occurrence of unwanted afterdischarges (ADs) impedes cortical stimulation for mapping purposes. We investigated the safety of several stimulation paradigms.
Methods: We compared the incidence of ADs and behavioral responses of two stimulation frequencies (50 and 100 Hz), at two intensities (1 and 0.2 ms pulse widths).
Results: Stimulation with 100 Hz was more likely to cause ADs than 50 Hz, and stimulation using 1 ms pulse width was more likely to cause ADs than 0.2 ms.
Conclusions: Stimulation using 50 Hz frequency with a pulse width of 0.2 ms might be safer during cortical mapping.