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VA Cooperative Studies Program (CSP)

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Neurocognition Deployment Health Study (NDHS) and CSP #566

Main study:
Neurocognition Deployment Health Study (NDHS) 

Follow-up study:
CSP #566: Neuropsychological and Mental Outcomes of Operation Iraqi Freedom (OIF): A Longitudinal Cohort Study 

Investigator Access

What's available

Research resources generated by this study are not available at this time. For more information about access in the future, contact

Study Characteristics 


  • To examine the impact of Iraq combat-zone deployment on neuropsychological outcomes, including neurobehavioral and emotional functioning
  • To examine potential health risk and protective factors relevant to neuropsychological outcomes
  • To determine the current prevalence of posttraumatic stress disorder (PTSD) and to prospectively examine changes in PTSD symptoms from a pre-deployment assessment through post-deployment and long-term follow-up assessments

Era of Service

Operation Iraqi Freedom (OIF)
Operation Enduring Freedom (OEF) 
Operation New Dawn (OND)


NDHS: Male and female active duty US Army soldiers serving between April 2003 and June 2005 

CSP #566: Surviving NDHS cohort members who provided consent to be re-contacted and who deployed for ≥30 days for OIF at least once since NDHS baseline

Study Design 

Prospective cohort

Time Period 

NDHS: 2003 - 2005

CSP #566: 2010 - 2014


Nationally dispersed sample. Soldiers recruited from battalion units originating from Fort Hood, TX and Fort Lewis, WA; follow-up study conducted nationally (travel by study teams at VA Healthcare Systems in Boston, MA and Puget Sound, WA).


NDHS: 1,595 participants

CSP #566: full sample=598 participants; neuropsychological subsample=306 participants

Response Rate

NDHS: 94% (Time 1), 75% (Time 2)

CSP #566: 53.4% (Time 3)

Recruitment Method    

NDHS: Battalion leaders were asked to refer potential participants at random

CSP #566: NDHS participants who gave prior permission to be re-contacted were contacted via telephone to determine their willingness to participate


NDHS: no compensation

CSP #566: $200 for survey, additional $200 for in-person subsample examination

Data Collected


  • Demographic and military information,
  • Risk factors for neuropsychological disorders (e.g., psychiatric disorders, brain injury),
  • Situational factors potentially affecting neuropsychological performance (e.g., sleep, alcohol use),
  • Neuropsychological outcomes (e.g., sustained attention, working memory/executive functioning, fine motor speed, cognitive efficiency)

CSP #566:

  • PTSD measures,
  • Head injury exposure,
  • Assessments of depression and anxiety,
  • Assessment of functional and occupational activities,
  • Deployment and post-deployment stress disorder,
  • Risk/protective factors

Data Collection Methods

NDHS: Data collected prior to Iraq deployment, and again within 90 days of redeployment via paper questionnaires completed in small groups and performance-based neuropsychological tests administered by health care personnel; military service record information was also abstracted.

CSP #566: Data collected at least 5 years after return from first OIF deployment via phone-based interviews and mailed survey-based assessment of all eligible participants. A randomly selected subset of these participants completed in-person, performance-based neuropsychological assessments.

Funding Sources 

NDHS: VA and Department of Defense

CSP #566: VA Cooperative Studies Program


NDHS: Jennifer Vasterling, PhD, Principal Investigator;

CSP #566: Patricia Crutchfield, Project Manager;  

Selected Publications 

Vasterling JJ, Proctor SP, Amoroso P, Kane R, Heeren T, White RF. Neuropsychological outcomes of army personnel following deployment to the Iraq war. JAMA. 2006 Aug 2;296(5):519-29.

Aslan M, Concato J, Peduzzi PN, Proctor SP, Schnurr PP, Marx BP, McFall M, Gleason T, Huang GD, Vasterling JJ. Design of "neuropsychological and mental health outcomes of operation Iraqi freedom: a longitudinal cohort study". J Investig Med. 2013 Mar;61(3):569-77.

Vasterling JJ, Aslan M, Proctor SP, Ko J, Marx BP, Jakupcak M, Schnurr PP, Gleason T, Huang GD, Concato J. Longitudinal Examination of Posttraumatic Stress Disorder as a Long-Term Outcome of Iraq War Deployment. Am J Epidemiol. 2016 Dec 1;184(11):796-805

Vasterling JJ, Aslan M, Lee LO, Proctor SP, Ko J, Jacob S, Concato J. Longitudinal Associations among Posttraumatic Stress Disorder Symptoms, Traumatic Brain Injury, and Neurocognitive Functioning in Army Soldiers Deployed to the Iraq War. J Int Neuropsychol Soc. 2017;23:1-13 [e-pub ahead of print].

More Information