title: Use of somatosensory-evoked potentials and cognitive event-related potentials in predicting outcomes of patients with severe traumatic brain injury.
abstract: OBJECTIVE
  This study was performed to evaluate the usefulness of somatosensory-evoked potentials (SEPs) and cognitive event-related potentials (ERPs) in predicting functional outcomes of severe traumatic brain injury patients.
  
  
  METHODS
  Prospective study of 22 patients with severe traumatic brain injury. Demographic information, Glasgow Coma Scale, and electrophysiologic measurements were recorded. Functional outcomes, as quantified by the Glasgow Outcome Scale-Extended, were obtained.
  
  
  RESULTS
  Bilateral absence of median nerve SEP was strongly predictive of the worst functional outcome. The specificity and positive predictive value of absent SEP for predicting death or persistent vegetative state at 6 mo after traumatic brain injury were as high as 100%. If the definition of unfavorable outcome was expanded to include Glasgow Outcome Scale-Extended 1-4, absence of ERP was equivalent to the absence of SEP in specificity and positive predictive value. On the other hand, normal ERPs showed higher sensitivity and negative predictive value for prognosticating the best outcomes compared with normal SEPs. If the definition of favorable outcome was expanded to include Glasgow Outcome Scale-Extended 5-8, ERP was still superior to SEP for prognosticating good outcome. Interestingly, the highest sensitivity and negative predictive value for favorable outcomes were associated with the presence of any discernible waveform.
  
  
  CONCLUSIONS
  Although median nerve SEP continues to make reliable prediction of ominous outcome in severe traumatic brain injury, the addition of the speech-evoked ERPs may be helpful in predicting favorable outcomes. The strength of the latter test seems to complement the weakness of the former.
authors.affiliation: Physical Medicine and rehabilitation Service, VA Palo Alto, Health Care System, Stanford University School of Medicine, Palo Alto, California 94304, USA.
authors.forename: Henry L
authors.initials: HL
authors.lastname: Lew
authors.forename: Sureyya
authors.initials: S
authors.lastname: Dikmen
authors.forename: Jefferson
authors.initials: J
authors.lastname: Slimp
authors.forename: Nancy
authors.initials: N
authors.lastname: Temkin
authors.forename: Eun Ha
authors.initials: EH
authors.lastname: Lee
authors.forename: David
authors.initials: D
authors.lastname: Newell
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Robinson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000150:complications / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D003071:Cognition; D004558:Electric Stimulation; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory; D005073:Evoked Potentials, Somatosensory; D015600:Glasgow Coma Scale; D006801:Humans; D015601:Injury Severity Score; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D013060:Speech; D013997:Time Factors; D016896:Treatment Outcome