Archives of Physical Medicine and Rehabilitation
Volume 89, Issue 12, Supplement , Pages S3-S15, December 2008

Recovery of Cognitive Function After Traumatic Brain Injury: A Multilevel Modeling Analysis of Canadian Outcomes

  • Bruce K. Christensen, PhD, CPsych

      Affiliations

    • Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
    • ,
  • Brenda Colella, MA

      Affiliations

    • Toronto Rehabilitation Institute, Toronto, ON, Canada
    • ,
  • Elizabeth Inness, MSc

      Affiliations

    • Toronto Rehabilitation Institute, Toronto, ON, Canada
    • University of Toronto, Toronto, ON, Canada
    • ,
  • Deborah Hebert, MSc (Kin)

      Affiliations

    • Toronto Rehabilitation Institute, Toronto, ON, Canada
    • University of Toronto, Toronto, ON, Canada
    • ,
  • Georges Monette, PhD

      Affiliations

    • Department of Mathematics and Statistics, York University, Toronto, ON, Canada
    • ,
  • Mark Bayley, MD, FRCP(C)

      Affiliations

    • Toronto Rehabilitation Institute, Toronto, ON, Canada
    • University of Toronto, Toronto, ON, Canada
    • ,
  • Robin E. Green, PhD, CPsych

      Affiliations

    • Toronto Rehabilitation Institute, Toronto, ON, Canada
    • University of Toronto, Toronto, ON, Canada
    • Corresponding Author InformationReprint requests to Robin Green, PhD, CPsych, Toronto Rehabilitation Institute, 550 University Ave, Toronto, ON, M5G 2A2, Canada

Abstract 

Christensen B, Colella B, Inness E, Hebert D, Monette G, Bayley M, Green RE. Recovery of cognitive function after traumatic brain injury: a multilevel modeling analysis of Canadian outcomes.

Objective

To ascertain patterns of cognitive recovery during the first year after traumatic brain injury (TBI). Specifically, differential recovery across cognitive domains was investigated.

Design

Prospective, longitudinal, naturalistic, 1-year follow-up study.

Setting

Large, urban inpatient neurorehabilitation program.

Participants

Patients (N=75) with moderate to severe TBI.

Interventions

Not applicable.

Main Outcome Measures

Patients with TBI were followed over the course of 1 year, during which participants' neuropsychological status was repeatedly evaluated at 3 time points (2, 5, and 12 months postinjury).

Results

Multilevel modeling results were consistent with previous research, demonstrating that recovery in the first year postinjury is asymptotic in nature, with more accelerated recovery occurring during the first 5 to 6 months. Importantly, results also suggest that recovery is not uniform across cognitive domains. From 2 to 5 months postinjury, steeper recovery curves were revealed for indices of memory, speeded executive function, verbal abstraction, and manual dexterity relative to untimed tests of executive function and word knowledge. Recovery trajectories did not significantly vary as a function of cognitive domain over the course of the last 5 to 12 months.

Conclusions

These results are the first to explore trajectories of recovery directly as a function of multiple cognitive domains. They are expected to have implications for rehabilitative efforts as well as our understanding of the architecture of natural recovery after TBI.

Key Words: Brain injuries, Cognition, Longitudinal studies, Neuropsychology, Rehabilitation

List of Abbreviations: ANOVA, analysis of variance, GCS, Glasgow Coma Scale, GOS, Glasgow Outcome Scale, IQ, intelligence quotient, PIQ, performance intelligence quotient, PTA, posttraumatic amnesia, RAVLT, Rey Auditory Verbal Learning Test, TBI, traumatic brain injury, VIQ, verbal intelligence quotient, WAIS-III, Wechsler Adult Intelligence Scale–3rd edition

 

 Supported by the Canadian Institutes of Health Research and the Physicians' Services Inc (grant nos. MOP-67072, 05-50).

 No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.

PII: S0003-9993(08)01498-6

doi:10.1016/j.apmr.2008.10.002

Archives of Physical Medicine and Rehabilitation
Volume 89, Issue 12, Supplement , Pages S3-S15, December 2008

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