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Use of Somatosensory-Evoked Potentials and Cognitive Event-Related Potentials in Predicting Outcomes of Patients with Severe Traumatic Brain Injury

Lew, Henry L. MD, PhD; Dikmen, Sureyya PhD; Slimp, Jefferson PhD; Temkin, Nancy PhD; Lee, Eun Ha MD, PhD; Newell, David MD; Robinson, Lawrence R. MD

American Journal of Physical Medicine & Rehabilitation:
CME Article*2003 Series*Number 1: Brain Injury
Abstract

Lew HL, Dikmen S, Slimp J, Temkin N, Lee EH, Newell D, Robinson LR: Use of somatosensory-evoked potentials and cognitive event-related potentials in predicting outcomes of patients with severe traumatic brain injury. Am J Phys Med Rehabil 2003;82:53–61.

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.

Design: 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.

Author Information

From the Physical Medicine and Rehabilitation Service, VA Palo Alto Health Care System, Stanford University School of Medicine, Palo Alto, California (HLL, EHL); and the Departments of Rehabilitation Medicine (SD, JS, NT, LRR) and Neurosurgery (DN), University of Washington/Harborview Medical Center, Seattle, Washington.

Supported by the National Institutes of Health grant 5K12HD01097.

Presented, in part, at the Annual Meeting of the Association of Academic Physiatrists, Hilton Head, South Carolina, March 1–3, 2001.

All correspondence and requests for reprints should be addressed to Henry L. Lew, MD, PhD, Comprehensive Rehabilitation Center, VAPAHCS, Physical Medicine and Rehabilitation Service, MS-B117, 3801 Miranda Avenue, Palo Alto, CA 94304.

Objectives: On completion of this article, the reader should be able to (1) recognize the relative predictive abilities of somatosensory-evoked potentials and cognitive event-related potentials in patients with severe traumatic brain injury and to (2) identify the different scales used in evaluating functional outcome in patients with traumatic brain injury.

Level: Advanced.

Accreditation: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to sponsor continuing medical education for physicians.

The Association of Academic Physiatrists designates this continuing medical education activity for a maximum of 1.5 credit hours in Category 1 of Physician’s Recognition Award of the American Medical Association. Each physician should claim only those hours of credit that he or she actually spent in the education activity.

Disclosure: Disclosure statements have been obtained regarding the authors’ relationships with financial supporters of this activity. There is no apparent conflict of interests related to the context of participation of the authors of this article.

How to Obtain CME Category 1 Credits

To obtain CME Category 1 credit, this educational activity must be completed and postmarked by December 31, 2004. Participants may read the article and take the exam issue by issue or wait to study several issues together. After reading the CME Article in this issue, participants may complete the Self-Assessment Exam by answering the questions on the CME Answering Sheet and the Evaluation pages, which appear later in this section. Send the completed forms to: Bradley R. Johns, Managing Editor, CME Department-AAP, American Journal of Physical Medicine & Rehabilitation, 7240 Fishback Hill Lane, Indianapolic, IN 46278. Documentation can be received at the AAP National Office at any time throughout the year, and accurate records will be maintained for each participant. CME certificates are issued only once a year in January for the total number of credits earned during the prior year.

© 2003 Lippincott Williams & Wilkins, Inc.