Table 1. Comparison between scalp EEG and intracranial EEG with subdural or depth electrodes

	Scalp EEG	Intracranial EEG
Invasiveness	Non-invasive	Invasive
Recording site	Scalp	1) Subdural electrode - Surface of cortex2) Depth electrode - Deep structure (e.g., hippocampus)
Region for evaluation	Whole brain	Limited to the area of craniotomy
Quality of EEG signals (e.g., epileptiform discharges)	Worse	Better
Interference by movement/ muscle artifact	Frequent	Rare
Functional brain mapping	Impossible	Possible

EEG, electroencephalography.