Deep white matter hyperintensities affect verbal memory independent of PTSD symptoms in veterans with mild traumatic brain injury

Abstract

Objective: Although white matter hyperintensity (WMH) pathology has been observed in the context of traumatic brain injury (TBI), the contribution of this type of macrostructural damage to cognitive and/or post-concussive symptomatology (PCS) remains unclear.

Methods: Sixty-eight Veterans (mTBI = 46, Military Controls [MCs] = 22) with and without history of mild TBI (mTBI) underwent structural MRI and comprehensive cognitive and psychiatric assessment. WMH volume was identified as deep (DWMH) or periventricular (PVWMH) on fluid-attenuated inversion recovery (FLAIR) images.

Results: Group analyses revealed that mTBI history was not associated with increased WMH pathology (p’s > 0.05). However, after controlling for post-traumatic stress disorder (PTSD) and intracranial volume, DWMH was associated with reduced short-and long-delayed memory performance within the mTBI group (p’s < 0.05). Additionally, after adjusting for PTSD and time since injury, regression analyses revealed that WMH was not associated with self-reported ratings of PCS (p’s > 0.05) in the mTBI group.

Conclusions: The results demonstrate that, in relatively young Veterans with mTBI, DWMH differentially and negatively affects memory performance above and beyond the effects of PTSD symptoms. The findings may help to clarify prior mixed results as well as offer focused treatment implications for Veterans with history of neurotrauma and evidence of macrostructural white matter damage.

Keywords:

• White matter hyperintensities
• white matter lesions
• WMH
• WML
• DWMH
• PVWMH
• periventricular lesions
• PVL
• deep white matter lesions
• DWML
• TBI
• PCS
• cognition
• neuropsychology
• traumatic brain injury
• postconcussive symptoms
• head trauma

Acknowledgements

The authors would like to thank all OEF/OIF/OND Veterans for their service, and we are extremely grateful to those who agreed to participate in this study. In addition, a special thanks is owed to the Veterans Affairs San Diego Healthcare System (VASDHS) Center for Stress and Mental Health (CESAMH) for their organizational assistance and to our dedicated research assistants (RK, EL, NL) who devote their time to our research laboratory.

Declaration of interest

This work was supported by grants awarded by the Veterans Affairs (Career Development Awards [CDA]: L.D.-W., D.S.; Merit Award; L.D.-W.) as well as the Department of Defense (Investigator-Initiated Research Grant [IIRG]: L.D.-W.). This material is further supported with resources of the Veterans Affairs Center of Excellence for Stress and Mental Health (CESAMH: L.D.-W.; D.S.).

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.