Neurologically critically ill patients must have the vital functions o
f their brains and nervous systems monitored. This article examines th
e principle of neurophysiologic monitoring and examines, from a case s
tudy viewpoint, four major monitoring systems routinely applied in the
management of these patients: intracranial pressure monitoring, conti
nuous electroencephalogram and evoked potentials, transcranial Doppler
, and cerebral blood flow and metabolism.