Measurement of Peripheral Vision Reaction Time Identifies White Matter Disruption in Patients with Mild Traumatic Brain Injury

Abstract

This study examined whether peripheral vision reaction time (PVRT) in patients with mild traumatic brain injury (mTBI) correlated with white matter abnormalities in centroaxial structures and impairments in neuropsychological testing. Within 24 h after mTBI, crossed reaction times (CRT), uncrossed reaction times (URT), and crossed-uncrossed difference (CUD) were measured in 23 patients using a laptop computer that displayed visual stimuli predominantly to either the left or the right visual field of the retina. The CUD is a surrogate marker of the interhemispheric transfer time (ITT). Within 7 days after the injury, patients received a diffusion tensor-MRI (DTI) scan and a battery of neuropsychological tests. Nine uninjured control subjects received similar testing. Patients 18-50 years of age were included if they had a post-resuscitation Glasgow Coma Scale >13 and an injury mechanism compatible with mTBI. Healthy controls were either age- and gender-matched family members of the TBI patients or healthy volunteers. CUD deficits >2 standard deviations (SD) were seen in 40.9% of patients. The CUD of injured patients correlated with mean diffusivity (MD) (p < 0.001, ρ = -0.811) in the posterior corpus callosum. Patients could be stratified on the basis of CUD on the Stroop 1, Controlled Oral Word Association Test (COWAT), and the obsessive-compulsive component of the Basic Symptom Inventory tests. These studies suggest that the PVRT indirectly measures white matter integrity in the posterior corpus callosum, a brain region frequently damaged by mTBI.

Microstructure of the Corpus Callosum Long after Pediatric Concussion

“…These findings were also supported by a study of adults who were at 1-year post-concussion (Hellstrøm et al, 2017). Similarly, altered diffusivity acutely after the concussion is associated with decreased verbal memory and executive functioning, and increased reaction time at 1-year post-injury (Geary et al, 2010;Womack et al, 2017). These studies suggest that microstructural alterations may underlie the cognitive and behavioral problems that present following concussion, but further research is needed to determine if these associations still hold true in children and adolescents long after injury.…”

“…Acutely following concussion, clinical or behavioral manifestations of white matter alterations may include worse post-concussion symptom severity and poorer cognitive performance (Geary, Kraus, Pliskin, & Little, 2010;Hellstrøm et al, 2017;Khong, Odenwald, Hashim, & Cusimano, 2016;Womack et al, 2017). A systematic review conducted by Khong and colleagues concluded that decreased FA and increased MD and RD are correlated with greater symptom severity and prolonged post-concussion symptoms (Khong et al, 2016).…”

Assessing Postconcussive Reaction Time Using Transport-Based Morphometry of Diffusion Tensor Images

“…The microstructure differentiating high and low reaction time was not perceptible visually as demonstrated in Fig 1, motivating the use of TBM 13,[26][27][28] to discover the complex pattern. Our 3D-TBM technique 13 is an image-transformation framework that fa- cilitates the discovery of this pattern through analysis in a transform domain.…”

“…Our 3D-TBM technique 13 is an image-transformation framework that fa- cilitates the discovery of this pattern through analysis in a transform domain. [26][27][28] On-line Fig 1 illustrates the system diagram in the On-line Appendix. The interested reader is referred to Kundu et al 13 for the mathematic derivation of 3D-TBM.…”

“…Computing Riemannian distances with respect to a common template allows linearization of the optimal mass transport metric and reduces the number of operations from N(NϪ1) / 2 to N. Prior work shows that pattern discrimination using the linear optimal transport distance is enabled when the template lies sufficiently close to the Riemannian manifold. 27,28 Because the TBM transformation is bijective, we can generate de novo images along the regression direction in transport space through inverse transformation. The latter is enabled because TBM is generative.…”