This is incorrect. In a brain-dead patient, the isoelectric EEG serves to demonstrate the absence of brain activity despite adequate perfusion and absence of sedation, i.e, even though the computer is plugged in and you've pressed the start button, nothing happens, and thus, nothing is likely to happen in the future.

Isoelectric EEG can be induced with propofol and barbiturates, either voluntarily (refractory epilepsy) or involuntarily (anesthesia), without any obvious ill effects once the sedation is off.