Prognostic value of evoked responses and event-related brain potentials in coma.
The behaviourally unresponsive patient, unable to exhibit the presence of cognition, constitutes a conundrum for health care specialists. Prognostic uncertainty impedes accurate management decisions and the application of ethical principles. An early, reliable prognosis is highly desirable. In this review investigations studying comatose patients with coma of different etiologies were selected. It is concluded that objective prognostication is enhanced by the use of electrophysiological tests. Persistent abnormalities of brainstem auditory evoked potentials and short-latency somatosensory evoked potentials reliably indicate the likelihood of irreversible neurological deficit or death. Meanwhile, the presence of "cognitive" event-related brain potentials (e.g., P300 and mismatch negativity) reflects the functional integrity of higher level information processing and, therefore, the likelihood of capacity for cognition. An approach that combines clinical and electrophysiological values provides optimal prediction of outcome and level of disability.
Wang
Jing Tian
JT
Cognitive Electrophysiology Laboratory, New York State Psychiatric Institute, New York, USA.
Young
G Bryan
GB
Connolly
John F
JF
D000161:Acoustic Stimulation; D001933:Brain Stem / Q000503:physiopathology*; D003128:Coma / Q000175:diagnosis* / Q000503:physiopathology; D004569:Electroencephalography; D018913:Event-Related Potentials, P300; D005071:Evoked Potentials; D005072:Evoked Potentials, Auditory; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D008606:Mental Processes; D011237:Predictive Value of Tests; D011379:Prognosis; D020127:Recovery of Function; D012720:Severity of Illness Index; D015599:Trauma Severity Indices