Journal of the International Neuropsychological Society

Brief Communications

White matter and neurocognitive changes in adults with chronic traumatic brain injury

MARY R.T. KENNEDYa1 c1, JEFFREY R. WOZNIAKa2, RYAN L. MUETZELa2, BRYON A. MUELLERa2, HSIN-HUEI CHIOUa1, KARI PANTEKOEKa1a2 and KELVIN O. LIMa2

a1 Department of Speech-Language-Hearing Sciences, University of Minnesota, Minneapolis, Minnesota

a2 Department of Psychiatry, University of Minnesota, Minneapolis, Minnesota

Abstract

Diffusion tensor imaging was used to investigate white matter (WM) integrity in adults with traumatic brain injury (TBI) and healthy adults as controls. Adults with TBI had sustained severe vehicular injuries on the average of 7 years earlier. A multivariate analysis of covariance with verbal IQ as the covariate revealed that adults with TBI had lower fractional anisotropy and higher mean diffusivity than controls, specifically in the three regions of interest (ROIs), the centrum semiovale (CS), the superior frontal (SPF), and the inferior frontal (INF). Adults with TBI averaged in the normal range in motor speed and two of three executive functions and were below average in delayed verbal recall and inhibition, whereas controls were above average. Time since injury, but not age, was associated with WM changes in the SPF ROI, whereas age, but not time since injury, was associated with WM changes in the INF ROI, suggesting that the effects of WM on time since injury may interact with age. To understand the utility of WM changes in chronic recovery, larger sample sizes are needed to investigate associations between cognition and WM integrity of severely injured individuals who have substantial cognitive impairment compared to severely injured individuals with little cognitive impairment. (JINS, 2009, 15, 130–136.)

(Received January 01 2008)

(Reviewed August 20 2008)

(Accepted August 20 2008)

Correspondence:

c1 Correspondence and reprint requests to: Mary R.T. Kennedy, Department of Speech-Language-Hearing Sciences and The Center for Cognitive Sciences, University of Minnesota, 115 Shevlin Hall, 164 Pillsbury Drive S.E., Minneapolis, Minnesota 55455. E-mail: kenne047@umn.edu.