Wartime blast induced mild traumatic brain injury in the military, damage to white matter tracts, and neuropsychological symptoms: a systematic review

Abstract

Chronic traumatic encephalopathy has originally been described in the 1950s in concussion-providing sports such as boxing. Since the early 2010s, the concept is used for Iraq and Afghanistan veterans suffering from long-lasting neuropsychological symptoms following blast-related mild traumatic brain injury. The aim of the work is to synthesize evidence regarding any correlation between wartime blast exposure in military veterans and damage to white matter tracts on neuroimaging. Systematic review conducted on Medline database from inception to 2024 using the MeSH terms "blast" and "white matter" in the title, looking for military patient series with extractable data correlating neuropsychological symptoms and damage to white matter tracts on diffusion tensor brain MRI. The research yielded 11 articles for a total of 544 patients, with a mean age of 32.9 (± 7.5) years-old, and male / female sex ratio of 21.6/1. Most frequently damage white matter tracts were the corticospinal tract (88.2%), anterior thalamic radiations (81.2%), cingulum (60.0%), SLF (55.9%), ILF (27.4%), the uncinate (27.1%), the fornices (27.1%). 5 articles (n = 293 patients) reported correlation between white matter tracts damage and physical symptoms, with direct correlation for the forceps major, the IFOF, the ILF. 7 articles (n = 455 blast patients) reported correlation between white matter tracts damage and PTSD, with direct correlation for the ILF and SLF. There is a growing body of evidence suggesting a correlation between blast-induced mTBI, microstructural damage to specific white matter tracts on diffusion tensor brain MRI, and neuropsychological symptoms (level of evidence 3a).

Keywords: Blast; Chronic traumatic encephalopathy; Diffusion tensor imaging; Mild traumatic brain injury; Posttraumatic stress disorder; White matter tracts.