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A multicentre study on the clinical utility of post-traumatic amnesia duration in predicting global outcome after moderate-severe traumatic brain injury
  1. W C Walker1,
  2. J M Ketchum2,
  3. J H Marwitz1,
  4. T Chen1,
  5. F Hammond3,
  6. M Sherer4,
  7. J Meythaler5
  1. 1
    Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University, Richmond, Virginia, USA
  2. 2
    Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, USA
  3. 3
    Carolinas Rehabilitation, Charlotte, North Carolina, USA
  4. 4
    TIRR Memorial Hermann, Houston, Texas, USA
  5. 5
    Department of Physical Medicine and Rehabilitation, Wayne State University, Detroit, Michigan, USA
  1. Correspondence to Dr W C Walker, Department of Physical Medicine and Rehabilitation, VCU, Box 980661, Richmond, VA 23298-0661, USA; wwalker{at}


Background: Past research shows that post-traumatic amnesia (PTA) duration is a particularly robust traumatic brain injury (TBI) outcome predictor, but low specificity limits its clinical utility.

Objectives: The current study assessed the relationship between PTA duration and probability thresholds for Glasgow Outcome Scale (GOS) levels.

Methods: Data were prospectively collected in this multicentre observational study. The cohort was a consecutive sample of rehabilitation patients enrolled in the National Institute on Disability and Rehabilitation Research funded TBI Model Systems (n = 1332) that had documented finite PTA duration greater than 24 h, and 1-year and 2-year GOS.

Results: The cohort had proportionally more Good Recovery (44% vs 39%) and less Severe Disability (19% vs 23%) at year 2 than at year 1. Longer PTA resulted in an incremental decline in probability of Good Recovery and a corresponding increase in probability of Severe Disability. When PTA ended within 4 weeks, Severe Disability was unlikely (<15% chance) at year 1, and Good Recovery was the most likely GOS at year 2. When PTA lasted beyond 8 weeks, Good Recovery was highly unlikely (<10% chance) at year 1, and Severe Disability was equal to or more likely than Moderate Disability at year 2.

Conclusions: Two PTA durations, 4 weeks and 8 weeks, emerged as particularly salient GOS probability thresholds that may aid prognostication after TBI.

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  • ▸ An additional table is published online only at

  • Funding Supported by grants H133A070036 (VCU TBI Model System), H133A070042 (Carolinas TBI Model System), H133A070043 (Texas TBI Model System of TIRR) from the National Institute on Disability and Rehabilitation Research, United States Department of Education.

  • Competing interests None.

  • Ethics approval Ethics approval was provided by each participating Model System Center: Virginia Commonwealth University, The Institute for Rehabilitation and Research (TIRR Memorial Hermann), Rehabilitation Institute of Michigan, Santa Clara Valley Medical Center, Ohio State University, Moss Rehabilitation Research Institute, University of Alabama, Craig Hospital, Emory University, Spaulding Rehabilitation Hospital, Mayo Clinic, University of Missouri, Methodist Rehabilitation Center, Carolinas Health Care System, University of Washington, JFK Johnson Rehabilitation Institute, University of Texas Southwestern Medical Center.

  • Patient consent Obtained.