Head impact accelerations for brain strain-related responses in contact sports: a model-based investigation

Both linear (alin) and rotational (arot) accelerations contribute to head impacts on the field in contact sports; however, they are often isolated in injury studies. It is critical to evaluate the feasibility of estimating brain responses using isolated instead of full degrees-of-freedom (DOFs) accelerations. In this study, we investigated the sensitivities of regional brain strain-related responses to resultant alin and arot as well as the relative contributions of these acceleration components to the responses via random sampling and linear regression using parameterized, triangulated head impacts with kinematic variable values based on on-field measurements. Two independently established and validated finite element models of the human head were employed to evaluate model consistency and dependency in results: the Dartmouth Head Injury Model (DHIM) and Simulated Injury Monitor (SIMon). For the majority of the brain, volume-weighted regional peak strain, strain rate, and von Mises stress accumulated from the simulation significantly correlated to the product of the magnitude and duration of arot, or effectively, the rotational velocity, but not to alin. Responses from arot-only were comparable to the full-DOFs counterparts especially when normalized by injury-causing thresholds (e.g., volume fractions of large differences virtually diminished (i.e., <1%) at typical difference percentage levels of 1–4% on average). These model-consistent results support the inclusion of both rotational acceleration magnitude and duration into kinematics-based injury metrics, and demonstrate the feasibility of estimating strain-related responses from isolated arot for analyses of strain-induced injury relevant to contact sports without significant loss of accuracy, especially for the cerebrum

Parasites of the Spotted Sucker, Minytrema melanops (Cypriniformes: Catostomidae) from Arkansas and Oklahoma

During October 2015, March and April 2016 and again between March and April 2017, 15 Spotted Sucker (Minytrema melanops) were collected from sites in the Ouachita (n = 5), Red (n = 1), and St. Francis (n = 5) river drainages, Arkansas, and the Arkansas River drainage, Oklahoma (n = 4), and examined for protozoan and metazoan parasites. Found were Calyptospora sp., Myxobolus sp., Pseudomurraytrema alabarrum, Biacetabulum banghami, Penarchigetes oklensis, and Acanthocephalus sp. New host and distributional records are documented for these parasites

Selected Helminth Parasites (Cestoda, Nematoda) of Bobcat, Lynx rufus (Carnivora: Felidae), in Northeastern Arkansas

The bobcat, Lynx rufus is a relatively common Arkansas carnivore that ranges statewide. Although there is a great deal of information on the natural history of this species in the state, there have been few studies where parasites have been documented in Arkansas bobcats. Here, a single specimen was examined and found to be infected with a tapeworm, Taenia rileyi and 2 nematodes, Toxoascaris leonina and Toxocara cati. We document the first record of T. rileyi from Arkansas and the first report of T. leonina from a bobcat in the state

Novel Reproductive Data on Pealip Redhorse, Moxostoma pisolabrum (Cypriniformes: Catostomidae), from Northeastern Arkansas

Little is known about the natural history of the Pealip Redhorse (Moxostoma pisolabrum), particularly on its reproductive biology in Arkansas. We examined 11 female M. pisolabrum collected in late February 2020 and 2021 from the Black River, Lawrence County. Egg mass (g) represented 9‒14% of the total weight of these gravid females. This is the first time information on female reproduction in this species has been reported from any population of M. pisolabrum in the state

Hemoparasites (Apicomplexa: Hepatozoon; Kinetoplastida: Trypanosoma) of Green Frogs, Rana clamitans (Anura: Ranidae) from Arkansas

The green frog, Rana clamitans, has been reported as a host of several hemoparasites, including trypanosomes and Hepatozoon spp. In Arkansas, however, there are no reports of any hemoparasites in R. clamitans nor from any other anuran from the state. We collected 9 green frogs from Polk County and blood was taken from their facial musculocutaneous vein in heparinized capillary tubes. Thin blood smears were also made and stained with DipQuick stain. Seven out of 9 (78%) R. clamitans were infected with hematozoans. Three (33%) were infected with an unknown species of Hepatozoon and 4 (44%) were infected with trypanosomes of 3 distinct morphologies. Mixed infections were found in 5 (56%) of the hosts. Here, we provide the first report of hemoparasites in R. clamitans from Arkansas, including morphometric data and photomicrographs of the infections

Age at Injury is Associated with the Long-Term Cognitive Outcome of Traumatic Brain Injuries

Abstract Introduction The association between age at injury (AAI) and long-term cognitive outcome of traumatic brain injuries (TBI) is debatable. Methods Eligible participants with a history of TBI from Alzheimer's Disease Neuroimaging Initiative were divided into a childhood TBI (cTBI) group (the AAI ≤ 21 years old) and an adult TBI (aTBI) group (the AAI > 21 years old). Results The cTBI group has a higher Everyday Cognition total score than the aTBI group. All perceived cognitive functions are worse for the cTBI group than for the aTBI group except memory. By contrast, the cTBI group has higher assessment scores on either the Boston Naming Test or Rey Auditory Verbal Learning Test than the aTBI group. Discussion The AAI is associated with the long-term cognitive outcomes in older adults with a history of TBI

Traumatic Brain Injury and Age at Onset of Cognitive Impairment in Older Adults

There is a deficiency of knowledge regarding how traumatic brain injury (TBI) is associated with age at onset (AAO) of cognitive impairment in older adults. Participants with a TBI history were identified from the Alzheimer's disease neuroimaging initiative (ADNI 1/GO/2) medical history database. Using an analysis of covariance (ANCOVA) model, the AAO was compared between those with and without TBI, and potential confounding factors were controlled. The AAO was also compared between those with mild TBI (mTBI) and moderate or severe TBI (sTBI). Lastly, the effects of mTBI were analyzed on the AAO of participants with clinical diagnoses of either mild cognitive impairment (MCI) or Alzheimer's disease (AD). The AAO for a TBI group was 68.2 ± 1.1 years [95 % confidence interval (CI) 66.2–70.3, n = 62], which was significantly earlier than the AAO for the non-TBI group of 70.9 ± 0.2 years (95 % CI 70.5–71.4, n = 1197) (p = 0.013). Participants with mTBI history showed an AAO of 68.5 ± 1.1 years (n = 56), which was significantly earlier than the AAO for the non-TBI group (p = 0.032). Participants with both MCI and mTBI showed an AAO of 66.5 ± 1.3 years (95 % CI 63.9–69.1, n = 45), compared to 70.6 ± 0.3 years for the non-TBI MCI group (95 % CI 70.1–71.1, n = 935) (p = 0.016). As a conclusion, a history of TBI may accelerate the AAO of cognitive impairment by two or more years. These results were consistent with reports of TBI as a significant risk factor for cognitive decline in older adults, and TBI is associated with an earlier AAO found in patients with MCI or AD

Hybrid Diffusion Imaging to Detect Acute White Matter Injury after Mild TBI

poster abstractIntroduction: In the present study we used multi-shell Hybrid Diffusion Imaging (HYDI) to study white matter changes in the acute stage of mild traumatic brain injury (mTBI). Non-parametric diffusion analysis, q-space imaging as well as parametric analyses including conventional DTI and novel neurite orientation dispersion and density imaging (NODDI) were used to analyze the HYDI data. Method: Nineteen mTBI patients and 23 trauma-controlled subjects were recruited from the Emergency Department. Participants received T1W SPGR and HYDI in a Philips 3T Achieve TX scanner with 8-channel head coil and SENSE parallel imaging. The diffusion-weighting (DW) pulse sequence scan-time was about 24 min similar to (1). Results: Forty-eight WM ROIs were defined in the standard MNI space by intersecting subjects’ mean WM skeleton with WM atlas of Johns Hopkins University (JHU) ICBM-DTI-81(2). Linear model analysis was used to test the significance of diffusion metrics between mTBI and trauma-controlled groups with gender and age as covariates (model 3 in Table 1). Maps of DTI, q-space and NODDI diffusion metrics of an mTBI subject are shown in Figure 1. Among various diffusion metrics, only the NODDI derived parenchymal axonal density (Vic) was sensitive to mTBI with significant decreases in 60% of WM ROIs (Table 1). The mTBI subjects had an approximately 4% decrease in Vic. The affected WM tracts concentrated on pyramidal tracts and its cortical projections (bilateral corona radiatae). Most of the cerebella related tracts and hippocampal tracts are spared. Conclusion: HYDI and its diffusion metrics provide insights about microstructural changes of WM in the acute stage of mTBI and may prove useful as a marker of injury