Investigating structural and perfusion deficits due to repeated head trauma in active professional fighters

Abstract

Repeated head trauma experienced by active professional fighters results in various structural, functional and perfusion damage. However, whether there are common regions of structural and perfusion damage due to fighting and whether these structural and perfusion differences are associated with neuropsychological measurements in active professional fighters is still unknown. To that end, T1-weighted and pseudocontinuous arterial spin labeling MRI on a group of healthy controls and active professional fighters were acquired. Voxelwise group comparisons, in a univariate and multivariate sense, were performed to investigate differences in gray and white matter density (GMD, WMD) and cerebral blood flow (CBF) between the two groups. A significantly positive association between global GMD and WMD was obtained with psychomotor speed and reaction time, respectively, in our cohort of active professional fighters. In addition, regional WMD deficit was observed in a cluster encompassing bilateral pons, hippocampus, and thalamus in fighters (0.49 ± 0.04 arbitrary units (a.u.)) as compared to controls (0.51 ± 0.05a.u.). WMD in the cluster of active fighters was also significantly associated with reaction time. Significantly lower CBF was observed in right inferior temporal lobe with both partial volume corrected (46.9 ± 14.93 ml/100 g/min) and non-partial volume corrected CBF maps (25.91 ± 7.99 ml/100 g/min) in professional fighters, as compared to controls (65.45 ± 22.24 ml/100 g/min and 35.22 ± 12.18 ml/100 g/min respectively). A paradoxical increase in CBF accompanying right cerebellum and fusiform gyrus in the active professional fighters (29.52 ± 13.03 ml/100 g/min) as compared to controls (19.43 ± 12.56 ml/100 g/min) was observed with non-partial volume corrected CBF maps. Multivariate analysis with both structural and perfusion measurements found the same clusters as univariate analysis in addition to a cluster in right precuneus. Both partial volume corrected and non-partial volume corrected CBF of the cluster in the thalamus had a significantly positive association with the number of fights. In addition, GMD of the cluster in right precuneus was significantly associated with psychomotor speed in our cohort of active professional fighters. Our results suggest a heterogeneous pattern of structural and CBF deficits due to repeated head trauma in active professional fighters. This finding indicates that investigating both structural and CBF changes in the same set of participants may help to understand the pathophysiology and progression of cognitive decline due to repeated head trauma.

Towards Understanding Comprehensive Morphometric Changes and Its Correlation with Cognition and Exposure to Fighting in Active Professional Boxers

“…Depending on the severity and the type of injury, RHI has been shown to produce a cascade of both regional and global brain atrophy (Bigler, 2013;Eierud et al, 2014;Gooijers et al, 2013;Koerte et al, 2015;Langlois et al, 2006). However, similar to our previous findings (Mishra et al, 2018), in our cohort of active professional fighters, we did not find any global or regional VBM differences between our current cohort of impaired and nonimpaired boxers. We speculate that regional or global atrophy due to RHI may lack both sensitivity and specificity for a significant group effect earlier in the pathological process, possibly due to the heterogeneous impact of brain injuries and the inherent repair mechanism of individual boxers.…”

Understanding white matter structural connectivity differences between cognitively impaired and nonimpaired active professional fighters

“…Magnetic resonance imaging (MRI) can be used to investigate changes in regional brain volumes, perfusion, structural connectivity [derived using diffusion‐weighted MRI (dMRI)], and functional connectivity in participants exposed to RHI. For instance, various structural neuroimaging studies of RHI due to combat sports and in veterans with blast injuries have shown changes in various gray matter volumes such as thalamus, ventromedial prefrontal cortices, right fusiform gyrus, and frontotemporolimbic regions involving hippocampus, medial temporal lobe, and frontal lobes (Bernick et al, ; Bigler, ; Gooijers et al, ; Lopez‐Larson et al, ; Mishra et al, , ; Montenigro, Bernick, & Cantu, ; Ng et al, ). Similarly, voxelwise dMRI‐derived measures such as fractional anisotropy (FA) and mean diffusivity (MD) have shown differences in the temporo‐occipital white matter tracts and forceps major (Hulkower, Poliak, Rosenbaum, Zimmerman, & Lipton, ; Mishra et al, ; Ng et al, ; Orrison et al, ; Shin et al, ; Wintermark, Sanelli, Anzai, Tsiouris, & Whitlow, ; Zhang et al, ; Zhang, Heier, Zimmerman, Jordan, & Ulug, ).…”

“…Similarly, voxelwise dMRI‐derived measures such as fractional anisotropy (FA) and mean diffusivity (MD) have shown differences in the temporo‐occipital white matter tracts and forceps major (Hulkower, Poliak, Rosenbaum, Zimmerman, & Lipton, ; Mishra et al, ; Ng et al, ; Orrison et al, ; Shin et al, ; Wintermark, Sanelli, Anzai, Tsiouris, & Whitlow, ; Zhang et al, ; Zhang, Heier, Zimmerman, Jordan, & Ulug, ). Finally, perfusion measures using arterial spin labeling (ASL) MRI has also shown significant deficits in the thalamus, cingulate gyri, cerebellum, cuneus, and temporal lobes (Eierud et al, ; Koerte et al, ; Mishra et al, ). Even multivariate MRI measures combining voxelwise volumetric, perfusion, and dMRI‐derived measures (Mishra et al, , ) have identified deficits in several brain regions that were correlated with exposure and neuropsychological scores in participants with RHI.…”

“…Finally, perfusion measures using arterial spin labeling (ASL) MRI has also shown significant deficits in the thalamus, cingulate gyri, cerebellum, cuneus, and temporal lobes (Eierud et al, ; Koerte et al, ; Mishra et al, ). Even multivariate MRI measures combining voxelwise volumetric, perfusion, and dMRI‐derived measures (Mishra et al, , ) have identified deficits in several brain regions that were correlated with exposure and neuropsychological scores in participants with RHI.…”

Molecular and Imaging Biomarkers in Alzheimer’s Disease: A Focus on Recent Insights

“…As stated above, the evaluation of whole hippocampal volume was not a well-suited biomarker during the pre-clinical AD stage. Several papers reported contradictory findings, potentially due to the use of different approaches in performing the analyses [ 123 ]. This could be related to the fact that the manual volumetric technique is a very challenging and time-consuming approach also requiring an excellent working knowledge of neuroanatomy as well as good skill in delineating regions of interest (ROI).…”