Article Text

PDF
Apolipoprotein E and traumatic brain injury in a military population: evidence of a neuropsychological compensatory mechanism?
  1. S Duke Han1,
  2. Angela I Drake2,
  3. Lynne M Cessante2,
  4. Amy J Jak3,
  5. Wes S Houston4,
  6. Dean C Delis5,
  7. J Vincent Filoteo5,
  8. Mark W Bondi5
  1. 1
    Department of Psychology, Loyola University Chicago, Chicago, Illinois, USA
  2. 2
    Defense and Veterans Brain Injury Center, Neurosciences Department, Naval, Medical Center San Diego, San Diego, California, USA
  3. 3
    Veterans Medical Research Foundation, San Diego, California, USA
  4. 4
    Department of Neurology, University of Iowa, Iowa City, Iowa, USA
  5. 5
    Department of Psychiatry, University of California San Diego School of Medicine, San Diego and Psychology Service, VA San Diego Healthcare System, San Diego, California, USA
  1. Dr Mark W Bondi, VA San Diego Healthcare System (116B), 3350 La Jolla Village Drive, San Diego, CA 92161, USA; mbondi{at}ucsd.edu

Abstract

Objective: Although research has implicated the apolipoprotein E (APOE) epsilon-4 genotype as having a negative effect on neuropsychological outcomes following traumatic brain injury (TBI), the potentially negative role of the ϵ4 allele on TBI outcomes has recently been challenged. In light of this debate, the present study served to examine the role of APOE genotype on neuropsychological outcomes approximately 1 month following mild to moderate TBI in a military population. Because of the well documented role of the APOE-ϵ4 allele in increasing the risk of Alzheimer’s disease, we predicted that persons with the APOE-ϵ4 genotype would display relatively greater deficits in cognition than their non-ϵ4 counterparts.

Methods: 78 participants were consecutively recruited following a mild to moderate TBI and were divided into two groups based on the presence or absence of an APOE ϵ4 allele. Groups were comparable on demographic characteristics and psychosocial outcomes. Participants were administered a comprehensive neuropsychological battery.

Results: Analyses revealed comparable performances on most neuropsychological measures and better performances by ϵ4 carriers on select measures of attention, executive functioning and episodic memory encoding. Furthermore, differences remained after accounting for the effects of TBI severity.

Conclusions: Evidence from these analyses supports current literature refuting the notion of relatively poorer neuropsychological functioning associated with the APOE-ϵ4 genotype among young adult participants shortly following mild or moderate brain injury. Neuropsychological performance differences by APOE genotype following TBI are discussed in terms of the importance of considering severity of injury, timing of postinjury assessment and possible neurocognitive compensatory mechanisms.

Statistics from Altmetric.com

Footnotes

  • Competing interests: Dr Delis is a co-author of the D-KEFS (Delis–Kaplan Executive Functions System) and receives royalties from the test. There were no other actual or potential conflicts of interest for the authors that could have inappropriately influenced the present work. Subjects were recruited in accordance with Internal Review Board (IRB) approved policies and procedures. Standard professional and ethical guidelines were upheld during the research study and manuscript preparation. The views expressed in this article do not necessarily reflect those of the funding agency, the United States Navy, the United States Marine Corps, the Department of Defense or the United States Government.

  • Abbreviations:
    AD
    Alzheimer’s disease
    APOE
    apolipoprotein E
    CVLT-II
    California Verbal Learning Test-second edition
    D-KEFS
    Delis–Kaplan Executive Functions System
    DVBIC
    Defense and Veterans Brain Injury Center
    GOS
    Glasgow Outcome Scale
    TBI
    traumatic brain injury
    WAIS-III
    Wechsler Adult Intelligence Scale-third edition
    WMS-III
    Wechsler Memory Scale-third edition

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.