American Clinical Neurophysiology Society Technical Standards for Electrical Stimulation With Intracranial Electrodes for Functional Brain Mapping and Seizure Induction.

PURPOSE

These American Clinical Neurophysiology Society technical standards suggest best practices for electrical stimulation mapping (ESM) with subdural and stereotactic depth electrodes for seizure induction and mapping of brain function.

METHODS

A working group was convened from American Clinical Neurophysiology Society membership with expertise in ESM. PubMed searches were performed to identify pertinent peer-reviewed literature. Recurrent meetings reviewed progress, built consensus by discussion, and developed evidence-based recommendations to the extent possible.

RECOMMENDATIONS

Stimulators used for ESM should have sufficient dynamic range, ability to interrupt a stimulus train, and ictal disrupt mechanism(s). Charge density should be calculated for the specific electrodes and ESM settings, the maximum safe limits being 52 to 57 μC/cm 2 /phase for subdural electrodes and not established for stereotactic depth electrodes. Subdural ESM for functional mapping is typically performed at 50-Hz pulse frequency, 200- to 300-µs pulse width, 2- to 8-s train duration, and 1- to 20-mA current strength. Stereo ESM is commonly performed using 2 different pulse frequencies: 1 Hz (300-500 µs pulse width, train duration up to 30 s, and often a constant current of 3-5 mA), and 50 Hz (100-500 µs pulse width, train duration 2-8 s, and 0.5-10 mA current intensity).

CONCLUSIONS

This guideline provides technical standards for the performance of ESM, which will likely evolve over time with advances in technology and additional evidence (also see Graphical Abstract).