Subjective memory complaints are associated with decreased cortical thickness in Veterans with histories of mild traumatic brain injury

Abstract

Objective: Memory problems are frequently endorsed in Veterans following mild traumatic brain injury (mTBI), but subjective complaints are poorly associated with objective memory performance. Few studies have examined associations between subjective memory complaints and brain morphometry. We investigated whether self-reported memory problems were associated with objective memory performance and cortical thickness in Veterans with a history of mTBI. Methods: 40 Veterans with a history of remote mTBI and 29 Veterans with no history of TBI completed the Prospective-Retrospective Memory Questionnaire (PRMQ), PTSD Checklist (PCL), California Verbal Learning Test-2nd edition (CVLT-II), and 3 T T1 structural magnetic resonance imaging. Cortical thickness was estimated in 14 a priori frontal and temporal regions. Multiple regressions adjusting for age and PCL scores examined associations between PRMQ, CVLT-II scores, and cortical thickness within each Veteran group. Results: Greater subjective memory complaints on the PRMQ were associated with lower cortical thickness in the right middle temporal gyrus (β = 0.64, q = .004), right inferior temporal gyrus (β = 0.56, q = .014), right rostral middle frontal gyrus (β = 0.45, q = .046), and right rostral anterior cingulate gyrus (β = 0.58, q = .014) in the mTBI group but not the control group (q’s > .05). These associations remained significant after adjusting for CVLT-II learning. CVLT-II performance was not associated with PRMQ score or cortical thickness in either group. Conclusions: Subjective memory complaints were associated with lower cortical thickness in right frontal and temporal regions, but not with objective memory performance, in Veterans with histories of mTBI. Subjective complaints post-mTBI may indicate underlying brain morphometry independently of objective cognitive testing.

Keywords:

• Mild traumatic brain injury
• concussion
• veterans
• subjective memory
• cortical thickness

Acknowledgements

We want to thank all of the Veterans that volunteered their time to participate in this study.

Data availability

The data that support the findings of this study are available from the corresponding author, MTL, upon reasonable request.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Veterans Affairs research grants including Career Development Awards to Drs. Sorg (IK2 CX001508) and Delano-Wood (CDA-2-034-07F) and a Merit Award to Dr. Delano-Wood (CX000842-01A2), as well as a Department of Defense Investigator-Initiated Research Grant awarded to Dr. Delano-Wood (W81XWH-10-2-0169). This material is further supported by resources of the Veterans Affairs Center of Excellence for Stress and Mental Health. Dr. Merritt received salary support during this work from a Career Development Award (IK2 CX001952) from the VA Clinical Science Research & Development Service. Ms. Ozturk received salary support during this work from the Graduate Research Fellowship from the National Science Foundation. Dr. Sorg received salary support during this work from a Veterans Affairs Merit Award (CX002246).