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Outcome after traumatic brain injury: Pathway analysis of contributions from premorbid, injury severity, and recovery variables,☆☆,,★★

https://doi.org/10.1053/apmr.2001.18222Get rights and content

Abstract

Novack TA, Bush BA, Meythaler JM, Canupp K. Outcome after traumatic brain injury: pathway analysis of contributions from premorbid, injury severity, and recovery variables. Arch Phys Med Rehabil 2001;82:300-5. Objective: To examine the relationship of premorbid variables, injury severity, and cognitive and functional status to outcome 1 year after traumatic brain injury (TBI) and to assess the feasibility of multivariate path analysis as a way to discover those relationships. Design: Prospective, longitudinal. Settings: Level I trauma center, acute inpatient rehabilitation hospital. Patients: One hundred seven subjects (87 men, 20 women; mean age, 33.91 ± 14.2 yr) who had experienced severe TBI, typically from motor vehicle crashes. Interventions: Acute medical and rehabilitation care. Main Outcome Measures: Disability Rating Scale, Community Integration Questionnaire, and return to employment. Evaluated in acute rehabilitation, and at 6 and 12 months' postinjury. Results: Path analyses revealed that premorbid factors had significant relationships with injury severity, functional skills, cognitive status, and outcome; injury severity affected cognitive and functional skills; and cognitive status influenced outcome. No significant relationships were found between injury severity and emotional status, injury severity and outcome, emotional status and outcome, and functional skills and outcome. Conclusions: Multivariate analysis is important to understanding outcome after TBI. Injury severity, as measured in this study, is less important to 12-month outcome than the premorbid status of the person and the difficulties (particularly cognitive deficits) exhibited at follow-up 6 months after the trauma.

Section snippets

Subjects

Of an eligible 169 persons admitted to an intensive care unit with a diagnosis of TBI and participating in acute rehabilitation, 107 participated in the present study. Subjects were identified as having TBI if they had experienced loss of consciousness of any duration, skull fracture, PTA of any duration, or had objective neurologic findings such as alteration in mentation, cranial nerve deficits, or hemiparesis. Subjects who completed the study participated in a neuropsychologic evaluation and

Results

The subjects completing the study (table 1) were predominantly young men with a high school education or less who were injured in motor vehicle collisions. Based on GCS2 score, a majority (70.1%) of the sample had experienced a severe TBI (GCS score, 3-8); 17.7% experienced a moderate TBI (GCS score, 9-12); and 12.1% experienced a mild TBI (GCS score, 13-15). In the case of mild injuries, subjects exhibited other problems that necessitated admission to the intensive care unit, such as

Discussion

The subjects in this study were young, mostly men, and had limited education (usually because they were too young at age of injury to have completed their education). Most injuries were from motor vehicle crashes, and there was a distribution of severity of injury, although severe TBI was predominant. The cognitive difficulties encountered were comparable to what has been described elsewhere,3, 20, 27 with deficits in memory functioning and speed of mental processing being particularly evident.

Conclusion

The results of the present study underscore the need for researchers to be very circumspect when examining the relationship of individual variables to outcome. Using only a few variables, or examining 1 aspect of TBI, one may identify a relationship that would not fare well in a multivariate study. For instance, the relation between Injury Severity and Outcome is likely to be stronger if no other variables that could contribute to outcome are considered. This misunderstanding might lead to

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  • Cited by (0)

    Supported in part by the Centers for Disease Control (grant no. R49CCR40364) and by the National Institutes of Health (grant no. HD07420).

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    No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the author(s) is/are associated.

    Reprint requests to Thomas A. Novack, PhD, University of Alabama at Birmingham, Spain Rehabilitation Center, Dept of Physical Medicine and Rehabilitation, 1717 6th Ave S, Birmingham, AL 35233, e-mail: [email protected].

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