Journal of the International Neuropsychological Society

Factors moderating neuropsychological outcomes following mild traumatic brain injury: A meta-analysis

HEATHER G.  BELANGER  a1 a2 a4 a5 c1 , GLENN  CURTISS  a1 a3 a4 , JASON A.  DEMERY  a1 a6 , BRIAN K.  LEBOWITZ  a1 a7 and RODNEY D.  VANDERPLOEG  a1 a2 a3 a4
a1 James A. Haley Veterans' Hospital, Tampa, Florida
a2 University of South Florida Department of Psychology, Tampa, Florida
a3 University of South Florida Department of Psychiatry, Tampa, Florida
a4 Defense and Veterans Brain Injury Center, Tampa, Florida
a5 Henry M. Jackson Foundation, Rockville, Maryland
a6 University of Florida, Department of Clinical and Health Psychology, Gainesville, Florida
a7 University of Cincinnati, Department of Psychology, Cincinnati, Ohio

Article author query
belanger hg   [PubMed][Google Scholar] 
curtiss g   [PubMed][Google Scholar] 
demery ja   [PubMed][Google Scholar] 
lebowitz bk   [PubMed][Google Scholar] 
vanderploeg rd   [PubMed][Google Scholar] 


There continues to be debate about the long-term neuropsychological impact of mild traumatic brain injury (MTBI). A meta-analysis of the relevant literature was conducted to determine the impact of MTBI across nine cognitive domains. The analysis was based on 39 studies involving 1463 cases of MTBI and 1191 control cases. The overall effect of MTBI on neuropsychological functioning was moderate (d = .54). However, findings were moderated by cognitive domain, time since injury, patient characteristics, and sampling methods. Acute effects (less than 3 months postinjury) of MTBI were greatest for delayed memory and fluency (d = 1.03 and .89, respectively). In unselected or prospective samples, the overall analysis revealed no residual neuropsychological impairment by 3 months postinjury (d = .04). In contrast, clinic-based samples and samples including participants in litigation were associated with greater cognitive sequelae of MTBI (d = .74 and .78, respectively at 3 months or greater). Indeed, litigation was associated with stable or worsening of cognitive functioning over time. The implications and limitations of these findings are discussed. (JINS, 2005, 11, 215–227.)

(Received July 8 2004)
(Revised November 26 2004)
(Accepted December 21 2004)

Key Words: Brain concussion; Head injury; Minor; Neuropsychological; Sequelae; Litigation.

c1 Reprint requests to: Heather Belanger, Ph.D., James A. Haley Veterans' Hospital, Physical Medicine and Rehabilitation—117, 13000 Bruce B. Downs Blvd., Tampa, FL 33612. E-mail: