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1.
J Cereb Blood Flow Metab ; : 271678X20978582, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33444087

RESUMO

Elevated carbon dioxide (CO2) in breathing air is widely used as a vasoactive stimulus to assess cerebrovascular functions under hypercapnia (i.e., "stress test" for the brain). Blood-oxygen-level-dependent (BOLD) is a contrast mechanism used in functional magnetic resonance imaging (fMRI). BOLD is used to study CO2-induced cerebrovascular reactivity (CVR), which is defined as the voxel-wise percentage BOLD signal change per mmHg change in the arterial partial pressure of CO2 (PaCO2). Besides the CVR, two additional important parameters reflecting the cerebrovascular functions are the arrival time of arterial CO2 at each voxel, and the waveform of the local BOLD signal. In this study, we developed a novel analytical method to accurately calculate the arrival time of elevated CO2 at each voxel using the systemic low frequency oscillations (sLFO: 0.01-0.1 Hz) extracted from the CO2 challenge data. In addition, 26 candidate hemodynamic response functions (HRF) were used to quantitatively describe the temporal brain reactions to a CO2 stimulus. We demonstrated that our approach improved the traditional method by allowing us to accurately map three perfusion-related parameters: the relative arrival time of blood, the hemodynamic response function, and CVR during a CO2 challenge.

2.
PLoS One ; 15(10): e0240162, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33064732

RESUMO

It has been documented that up to 22% of all soccer injuries are concussions. This is in part due to players purposely using their head to direct the ball during play. To provide a more complete understanding of head trauma in soccer athletes, this study characterized the effects of four soccer ball characteristics (size, inflation pressure, mass, velocity) on the resulting peak impact force as it relates to the potential for incurring neurophysiological changes. A total of six hundred trials were performed on size 4 and 5 soccer balls as well as a novel lightweight soccer ball. Impact force was measured with a force plate and ball velocity was determined using motion capture. These data were used, in conjunction with dimensional analysis to relate impact force to ball size, mass, velocity, and pressure. Reasonable reductions in allowable ball parameters resulted in a 19.7% decrease in peak impact force. Adjustments to ball parameters could reduce a high cumulative peak translational acceleration soccer athlete down into a previously defined safer low loading range. In addition, it was noted that water absorption by soccer balls can result in masses that substantially increase impact force and quickly surpass the NCAA weight limit for game play. Additional research is required to determine whether varying soccer ball characteristics will enable soccer players to avoid persistent neurophysiological deficits or what additional interventions may be necessary and the legal implications of these data are discussed.

3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3581-3585, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018777

RESUMO

Infrared neural stimulation (INS) is an optical stimulation technique which uses coherent light to stimulate nerves and neurons and which shows increased spatial selectivity compared to electrical stimulation. This could improve deep brain, high channel count, or vagus nerve stimulation. In this study, we seek to understand the wavelength dependence of INS in the near-infrared optical window. Rat sciatic nerves were excised ex vivo and stimulated with wavelengths between 700 and 900 nm. Recorded compound nerve action potentials (CNAPs) showed that stimulation was maximized in the 700 nm window despite comparable laser power levels across wavelengths. Computational models demonstrated that wavelength-based activation dependencies were not a result of passive optical properties. This data demonstrates that INS is both wavelength and power level dependent, which inform stimulation systems to actively target neural microcircuits in humans.


Assuntos
Raios Infravermelhos , Nervo Isquiático , Animais , Estimulação Elétrica , Lasers , Ondas de Rádio , Ratos
4.
J Biophotonics ; 13(11): e202000173, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32706517

RESUMO

Vasoactive stress tests (i.e. hypercapnia, elevated partial pressure of arterial CO2 [PaCO2 ]) are commonly used in functional MRI (fMRI), to induce cerebral blood flow changes and expose hidden perfusion deficits in the brain. Compared with fMRI, near-infrared spectroscopy (NIRS) is an alternative low-cost, real-time, and non-invasive tool, which can be applied in out-of-hospital settings. To develop and optimize vasoactive stress tests for NIRS, several hypercapnia-induced tasks were tested using concurrent-NIRS/fMRI on healthy subjects. The results indicated that the cerebral and extracerebral reactivity to elevated PaCO2 depended on the rate of the CO2 increase. A steep increase resulted in different cerebral and extracerebral reactivities, leading to unpredictable NIRS measurements compared with fMRI. However, a ramped increase, induced by ramped-CO2 inhalation or breath-holding tasks, induced synchronized cerebral, and extracerebral reactivities, resulting in consistent NIRS and fMRI measurements. These results demonstrate that only tasks that increase PaCO2 gradually can produce reliable NIRS results.

5.
Annu Rev Biomed Eng ; 22: 387-407, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32348156

RESUMO

Subconcussive head injury represents a pathophysiology that spans the expertise of both clinical neurology and biomechanical engineering. From both viewpoints, the terms injury and damage, presented without qualifiers, are synonymously taken to mean a tissue alteration that may be recoverable. For clinicians, concussion is evolving from a purely clinical diagnosis to one that requires objective measurement, to be achieved by biomedical engineers. Subconcussive injury is defined as subclinical pathophysiology in which underlying cellular- or tissue-level damage (here, to the brain) is not severe enough to present readily observable symptoms. Our concern is not whether an individual has a (clinically diagnosed) concussion, but rather, how much accumulative damage an individual can tolerate before they will experience long-term deficit(s) in neurological health. This concern leads us to look for the history of damage-inducing events, while evaluating multiple approaches for avoiding injury through reduction or prevention of the associated mechanically induced damage.

6.
Clin J Sport Med ; 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32032162

RESUMO

OBJECTIVE: The goal of this pilot study was to evaluate the number of head acceleration events (HAEs) based on position, play type, and starting stance. DESIGN: Prospective cohort study. SETTING: Postcollegiate skill development camp during practice sessions and 1 exhibition game. PARTICIPANTS: Seventy-eight male adult North American football athletes. INDEPENDENT VARIABLES: A position was assigned to each participant, and plays in the exhibition game were separated by play type for analysis. During the exhibition game, video data were used to determine the effects of the starting position ("up" in a 2-point stance or "down" in a 3- or 4-point stance) on the HAEs experienced by players on the offensive line. MAIN OUTCOME MEASURES: Peak linear acceleration and number of HAEs greater than 20 g (g = 9.81 m/s) were measured using an xPatch (X2 Biosystems, Seattle, WA). RESULTS: Four hundred thirty-seven HAEs were recorded during practices and 272 recorded during the exhibition game; 98 and 52 HAEs, the greatest number of HAEs by position in the game, were experienced by the offensive and defensive linemen, respectively. Linebackers and tight ends experienced high percentages of HAEs above 60 g. Offensive line players in a down stance had a higher likelihood of sustaining a HAE than players in an up stance regardless of the type of play (run vs pass). CONCLUSIONS: Changing the stance of players on the offensive line and reducing the number of full-contact practices will lower HAEs.

7.
Brain Imaging Behav ; 14(1): 164-174, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30377933

RESUMO

Mitigating the effects of repetitive exposure to head trauma has become a major concern for the general population, given the growing body of evidence that even asymptomatic exposure to head accelerations is linked with increased risk for negative life outcomes and that risk increases as exposure is prolonged over many years. Among women's sports, soccer currently exhibits the highest growth in participation and reports the largest number of mild traumatic brain injuries annually, making female soccer athletes a relevant population in assessing the effects of repetitive exposure to head trauma. Cerebrovascular biomarkers may be useful in assessing the effects of repetitive head trauma, as these are thought to contribute directly to neurocognitive symptoms associated with mild traumatic brain injury. Here we use fMRI paired with a hypercapnic breath hold task along with monitoring of head acceleration events, to assess the relationship between cerebrovascular brain changes and exposure to repetitive head trauma over a season of play in female high school soccer athletes. We identified longitudinal changes in cerebrovascular reactivity that were significantly associated with prolonged accumulation to high magnitude (> 75th percentile) head acceleration events. Findings argue for active monitoring of athletes during periods of exposure to head acceleration events, illustrate the importance of collecting baseline (i.e., pre-exposure) measurements, and suggest modeling as a means of guiding policy to mitigate the effects of repetitive head trauma.


Assuntos
Concussão Encefálica/etiologia , Encéfalo/diagnóstico por imagem , Traumatismos Craniocerebrais/fisiopatologia , Aceleração , Adolescente , Atletas , Traumatismos em Atletas/complicações , Concussão Encefálica/diagnóstico por imagem , Feminino , Humanos , Hipercapnia/fisiopatologia , Imagem por Ressonância Magnética/métodos , Futebol/lesões , Futebol/fisiologia
8.
IEEE Trans Comput Imaging ; 5(4): 596-605, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31875167

RESUMO

Magnetic resonance imaging (MRI) plays a critical role in visualizing the structure and functions of the human body. In order to accelerate imaging time and improve image quality, radio-frequency (RF) coil receive arrays are commonly employed to acquire the magnetic resonance (MR) signal. Similarly, multiple transmit coils have been shown to accelerate and refine RF excitation. In this work, we investigate the optimization of total imaging time and image accuracy when considering both the transmit and receive coil arrays; we term this strategy multiple-input multiple-output (MIMO) MRI. Our RF pulse design method is modeled by minimizing the excitation errors while simultaneously maximizing the signal-to-noise ratio (SNR) of the reconstructed MR image. It further allows a key tradeoff between the two optimizers. Additionally, multiple acceleration factors, varying numbers of receive coils used, maximum excitation error tolerance, and different excitation patterns are simulated and analyzed in this model. For a given excitation pattern, our method is shown to improve the SNR by 18-130% under certain acceleration schemes, as compared to conventional parallel transmission methods, while simultaneously controlling the excitation error within a desired scope (NRMSE ≤ 0.12).

9.
Neuroimage Clin ; 24: 101930, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31630026

RESUMO

Recent evidence of short-term alterations in brain physiology associated with repeated exposure to moderate intensity subconcussive head acceleration events (HAEs), prompts the question whether these alterations represent an underlying neural injury. A retrospective analysis combining counts of experienced HAEs and longitudinal diffusion-weighted imaging explored whether greater exposure to incident mechanical forces was associated with traditional diffusion-based measures of neural injury-reduced fractional anisotropy (FA) and increased mean diffusivity (MD). Brains of high school athletes (N = 61) participating in American football exhibited greater spatial extents (or volumes) experiencing substantial changes (increases and decreases) in both FA and MD than brains of peers who do not participate in collision-based sports (N = 15). Further, the spatial extents of the football athlete brain exhibiting traditional diffusion-based markers of neural injury were found to be significantly correlated with the cumulative exposure to HAEs having peak translational acceleration exceeding 20 g. This finding demonstrates that subconcussive HAEs induce low-level neurotrauma, with prolonged exposure producing greater accumulation of neural damage. The duration and extent of recovery associated with periods in which athletes do not experience subconcussive HAEs now represents a priority for future study, such that appropriate participation and training schedules may be developed to minimize the risk of long-term neurological dysfunction.


Assuntos
Aceleração/efeitos adversos , Atletas , Encéfalo/diagnóstico por imagem , Futebol Americano/lesões , Estudantes , Substância Branca/diagnóstico por imagem , Adolescente , Concussão Encefálica/diagnóstico por imagem , Concussão Encefálica/etiologia , Imagem de Difusão por Ressonância Magnética/tendências , Cabeça/diagnóstico por imagem , Humanos , Masculino , Instituições Acadêmicas/tendências
10.
J Biomech ; 95: 109313, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31495519

RESUMO

It has been established that substantial negative changes in neurocognitive function can be observed in a large percentage of athletes who participate in contact sports such as soccer or football, motivating a need for improved safety systems. Head accelerations in men's lacrosse are similar to those in football and female lacrosse players experience high rates of concussions, necessitating better head protection in both sports. Previous studies have sought to evaluate the ability of modern football helmets to mitigate impacts both normal and oblique to the surface of the helmet using a system that quantifies both the input load and the resulting accelerations of a Hybrid III headform. This study quantifies the inputs and outputs of the helmet-Hybrid III headform system in order to compare the impact attenuation capability of two male and two female lacrosse helmets. Of those helmets tested, the better performing male helmet was the Schutt Stallion 650 and the better performing female helmet was the Hummingbird excepting device failure at the rear boss impact location, but football helmets still generally outperformed the lacrosse helmets tested here.


Assuntos
Dispositivos de Proteção da Cabeça , Teste de Materiais/instrumentação , Fenômenos Mecânicos , Esportes com Raquete , Equipamentos Esportivos , Aceleração , Atletas , Concussão Encefálica/prevenção & controle , Feminino , Humanos , Masculino , Esportes com Raquete/lesões
11.
Neuroimage ; 202: 115967, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31352124

RESUMO

Multi-site studies are becoming important to increase statistical power, enhance generalizability, and to improve the likelihood of pooling relevant subgroups together-activities which are otherwise limited by the availability of subjects or funds at a single site. Even with harmonized imaging sequences, site-dependent variability can mask the advantages of these multi-site studies. The aim of this study was to assess multi-site reproducibility in resting-state functional connectivity "fingerprints", and to improve identifiability of functional connectomes. The individual fingerprinting of functional connectivity profiles is promising due to its potential as a robust neuroimaging biomarker with which to draw single-subject inferences. We evaluated, on two independent multi-site datasets, individual fingerprints in test-retest visit pairs within and across two sites and present a generalized framework based on principal component analysis to improve identifiability. Those principal components that maximized differential identifiability of a training dataset were used as an orthogonal connectivity basis to reconstruct the individual functional connectomes of training and validation sets. The optimally reconstructed functional connectomes showed a substantial improvement in individual fingerprinting of the subjects within and across the two sites and test-retest visit pairs relative to the original data. A notable increase in ICC values for functional edges and resting-state networks were also observed for reconstructed functional connectomes. Improvements in identifiability were not found to be affected by global signal regression. Post-hoc analyses assessed the effect of the number of fMRI volumes on identifiability and showed that multi-site differential identifiability was for all cases maximized after optimal reconstruction. Finally, the generalizability of the optimal set of orthogonal basis of each dataset was evaluated through a leave-one-out procedure. Overall, results demonstrate that the data-driven framework presented in this study systematically improves identifiability in resting-state functional connectomes in multi-site studies.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma/normas , Imagem por Ressonância Magnética/normas , Estudos Multicêntricos como Assunto/normas , Rede Nervosa/diagnóstico por imagem , Adolescente , Adulto , Encéfalo/fisiologia , Estudos de Coortes , Conectoma/métodos , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Estudos Multicêntricos como Assunto/métodos , Rede Nervosa/fisiologia , Adulto Jovem
12.
J Neurotrauma ; 36(20): 2831-2849, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31062655

RESUMO

Competitive sport participation, in contact and collision sports, exposes athletes to repetitive head impacts. Although these impacts do not always result in overt symptomology or a diagnosed "concussion," evidence indicates that cumulative repetitive impacts affect brain pathophysiology. The purpose of this study was to perform a systematic review of prospective, longitudinal trials evaluating repetitive head impact exposure on white matter (WM) microstructure in collision and contact sport athletes to inform clinical care and treatment strategies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to determine studies that met predetermined inclusion and exclusion criteria. Initially, 2498 abstracts were identified, and 20 studies were critically evaluated herein. The majority of studies demonstrated significant longitudinal changes in anisotropy and/or diffusivity metrics that were associated with the quantity and/or the magnitude of head impact exposure, highlighting the utility of diffusion tensor imaging (DTI) for measuring changes in WM microstructure. Our review also comments on study methodology and describes how age, sex, sport, and time between sport cessation and DTI measures contribute to divergent findings within the literature. Suggestions for future research are also provided to overcome previous study limitations and maximize our understanding of the role of repetitive head impact exposure on WM integrity and long-term neurological sequela.


Assuntos
Atletas , Traumatismos em Atletas/diagnóstico por imagem , Traumatismos em Atletas/epidemiologia , Concussão Encefálica/diagnóstico por imagem , Concussão Encefálica/epidemiologia , Imagem de Tensor de Difusão/tendências , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Masculino , Estudos Prospectivos
13.
J Neurotrauma ; 36(7): 1115-1124, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30351182

RESUMO

This candidate gene study evaluated the relationship of a past history of concussion with single nucleotide polymorphisms (SNPs) in nine genes in a small cohort (N = 87) of a nationally ranked Division I football team. Genes and SNPs studied were selected based on their published connection to brain injury and brain development, as well as impulsivity. We used multinomial logistic regression analysis (MLRA) to quantify how well genotype predicted the number of previously diagnosed concussions (three categories: none, one, two or more), while covarying race and number of years participating in football. The rs4504469 SNP for KIAA0319 was the only locus that significantly predicted number of previously diagnosed concussions (p = 0.005, meeting Bonferroni correction for multiple comparisons). The KIAA0319 results raise the hypothesis that having the CT or TT genotype of KIAA0319 may be predictive of a lower incidence of previously diagnosed concussion. This finding raises a number of hypotheses for future pre-clinical research, particularly whether alterations in neural organization related to KIAA0319 rs4504469 lead to reduced susceptibility for lasting head trauma, or greater resilience in the face of repeated subconcussive injury.


Assuntos
Traumatismos em Atletas/genética , Concussão Encefálica/genética , Proteínas do Tecido Nervoso/genética , Polimorfismo de Nucleotídeo Único , Alelos , Futebol Americano , Genótipo , Humanos , Masculino , Projetos Piloto
14.
J Neurotrauma ; 36(8): 1343-1351, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30343622

RESUMO

This prospective controlled observational cohort study assessed the performance of a novel panel of serum microRNA (miRNA) biomarkers on indicators of concussion, subconcussive impacts, and neurocognitive function in collegiate football players over the playing season. Male collegiate student football athletes participating in a Division I Football Bowl Subdivision of the National Collegiate Athletic Association (NCAA) were enrolled. There were a total of 53 participants included in the study, 30 non-athlete control subjects and 23 male collegiate student football athletes. Neurocognitive assessments and blood samples were taken within the week before the athletic season began and within the week after the last game of the season and measured for a panel of pre-selected miRNA biomarkers. All the athletes had elevated levels of circulating miRNAs at the beginning of the season compared with control subjects (p < 0.001). Athletes with the lowest standard assessment of concussion (SAC) scores at the beginning of the season had the highest levels of miRNAs. The area under the curve (AUC) for predicting pre-season SAC scores were miR-195 (0.90), miR-20a (0.89), miR-151-5p (0.86), miR-505* (0.85), miR-9-3p (0.77), and miR-362-3p (0.76). In athletes with declining neurocognitive function over the season, concentrations of miRNAs increased over same period. There were significant negative correlations with miR-505* (p = 0.011), miR-30d (p = 0.007), miR-92 (p = 0.033), and (p = 0.008). The miRNAs correlating with balance problems were miR-505* (p = 0.007), miR-30d (p = 0.028), and miR-151-5p (p = 0.023). Those correlating with poor reaction times were miR-20a (0.043), miR-505* (p = 0.049), miR-30d (p = 0.031), miR-92 (p = 0.015), and miR-151-5p (p = 0.044). Select miRNAs were associated with baseline concussion assessments at the beginning of the season and with neurocognitive changes from pre to post-season in collegiate football players. Should these findings be replicated in a larger cohort of athletes, these markers could potentially serve as measures of neurocognitive status in athletes at risk for concussion and subconcussive injuries.


Assuntos
Biomarcadores/sangue , Concussão Encefálica/sangue , Futebol Americano/lesões , RNA Mensageiro/sangue , Atletas , Estudos de Coortes , Humanos , Masculino , Estudos Prospectivos , Recuperação de Função Fisiológica/fisiologia , Adulto Jovem
15.
Brain Imaging Behav ; 13(3): 735-749, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29802602

RESUMO

Long term neurological impairments due to repetitive head trauma are a growing concern for collision sport athletes. American Football has the highest rate of reported concussions among male high school athletes, a position held by soccer for female high school athletes. Recent research has shown that subconcussive events experienced by collision sport athletes can be a further significant source of accrued damage. Collision sport athletes experience hundreds of subconcussive events in a single season, and these largely go uninvestigated as they produce no overt clinical symptoms. Continued participation by these seemingly uninjured athletes is hypothesized to increase susceptibility to diagnoseable brain injury. This study paired magnetic resonance spectroscopy with head impact monitoring to quantify the relationship between metabolic changes and head acceleration event characteristics in high school-aged male football and female soccer collision sport athletes. During the period of exposure to subconcussive events, asymptomatic male (football) collision sport athletes exhibited statistically significant changes in concentrations of glutamate+glutamine (Glx) and total choline containing compounds (tCho) in dorsolateral prefrontal cortex, and female (soccer) collision sport athletes exhibited changes in glutamate+glutamine (Glx) in primary motor cortex. Neurometabolic alterations observed in football athletes during the second half of the season were found to be significantly associated with the average acceleration per head acceleration events, being best predicted by the accumulation of events exceeding 50 g. These marked deviations in neurometabolism, in the absence of overt symptoms, raise concern about the neural health of adolescent collision-sport athletes and suggest limiting exposure to head acceleration events may help to ameliorate the risk of subsequent cognitive impairment.


Assuntos
Traumatismos em Atletas/psicologia , Concussão Encefálica/fisiopatologia , Adolescente , Atletas , Concussão Encefálica/diagnóstico , Feminino , Futebol Americano/lesões , Humanos , Imagem por Ressonância Magnética , Espectroscopia de Ressonância Magnética/métodos , Masculino , Córtex Pré-Frontal/lesões , Futebol/lesões
16.
Handb Clin Neurol ; 158: 245-255, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30482352

RESUMO

Even impacts that do not immediately elicit symptoms of a concussion can induce changes in neural integrity. Because these so-called "subconcussive" head acceleration events, or head impact exposures, do not elicit identifiable symptoms, athletes continue to participate with unclear consequences. Neuroimaging studies reveal that neurologic changes, including inflammation, are associated with repetitive head impact exposures. Given that brain changes have been observed in athletes following repetitive head impact exposure, it is important to understand better and mitigate against this phenomenon. It is important to transition from the metric of concussion alone to one that includes repetitive head impact exposure, including the development of models that address why brain integrity may be compromised, who is at risk, and how to mitigate the risk of such exposure. Future work can include a health-monitoring framework to effect change and promote athlete safety.


Assuntos
Traumatismos em Atletas/complicações , Concussão Encefálica/diagnóstico , Concussão Encefálica/etiologia , Traumatismos em Atletas/diagnóstico , Diagnóstico Precoce , Humanos , Monitorização Fisiológica , Neuroimagem/métodos
17.
J Head Trauma Rehabil ; 33(1): 1-6, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28520677

RESUMO

OBJECTIVE: To evaluate the effectiveness of the electroencephalographic (EEG) Brain Function Index (BFI) for characterizing sports-related concussive injury and recovery. PARTICIPANTS: Three hundred fifty-four (354) male contact sport high school and college athletes were prospectively recruited from multiple locations over 6 academic years of play (244 control baseline athletes and 110 athletes with a concussion). METHODS: Using 5 to 10 minutes of eyes closed resting EEG collected from frontal and frontotemporal regions, a BFI was computed for all subjects and sessions. Group comparisons were performed to test for the significance of the difference in the BFI score between the controls at baseline and athletes with a concussion at several time points. RESULTS: There was no significant difference in BFI between athletes with a concussion at baseline (ie, prior to injury) and controls at baseline (P = .4634). Athletes with a concussion, tested within 72 hours of injury, exhibited significant differences in BFI compared with controls (P = .0036). The significant differences in BFI were no longer observed at 45 days following injury (P = .19). CONCLUSION: Controls and athletes with a concussion exhibited equivalent BFI scores at preseason baseline. The concussive injury (measured within 72 hours) significantly affected brain function reflected in the BFI in the athletes with a concussion. The BFI of the athletes with a concussion returned to levels seen in controls by day 45, suggesting recovery. The BFI may provide an important objective marker of concussive injury and recovery.


Assuntos
Traumatismos em Atletas/fisiopatologia , Concussão Encefálica/fisiopatologia , Encéfalo/fisiopatologia , Eletroencefalografia , Recuperação de Função Fisiológica/fisiologia , Adolescente , Estudos de Casos e Controles , Humanos , Masculino , Testes Neuropsicológicos , Fatores de Tempo , Adulto Jovem
18.
Neuroimage Clin ; 14: 708-718, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28393012

RESUMO

The cumulative effect of repetitive subconcussive collisions on the structural and functional integrity of the brain remains largely unknown. Athletes in collision sports, like football, experience a large number of impacts across a single season of play. The majority of these impacts, however, are generally overlooked, and their long-term consequences remain poorly understood. This study sought to examine the effects of repetitive collisions across a single competitive season in NCAA Football Bowl Subdivision athletes using advanced neuroimaging approaches. Players were evaluated before and after the season using multiple MRI sequences, including T1-weighted imaging, diffusion tensor imaging (DTI), arterial spin labeling (ASL), resting-state functional MRI (rs-fMRI), and susceptibility weighted imaging (SWI). While no significant differences were found between pre- and post-season for DTI metrics or cortical volumes, seed-based analysis of rs-fMRI revealed significant (p < 0.05) changes in functional connections to right isthmus of the cingulate cortex (ICC), left ICC, and left hippocampus. ASL data revealed significant (p < 0.05) increases in global cerebral blood flow (CBF), with a specific regional increase in right postcentral gyrus. SWI data revealed that 44% of the players exhibited outlier rates (p < 0.05) of regional decreases in SWI signal. Of key interest, athletes in whom changes in rs-fMRI, CBF and SWI were observed were more likely to have experienced high G impacts on a daily basis. These findings are indicative of potential pathophysiological changes in brain integrity arising from only a single season of participation in the NCAA Football Bowl Subdivision, even in the absence of clinical symptoms or a diagnosis of concussion. Whether these changes reflect compensatory adaptation to cumulative head impacts or more lasting alteration of brain integrity remains to be further explored.


Assuntos
Concussão Encefálica/diagnóstico por imagem , Concussão Encefálica/etiologia , Mapeamento Encefálico , Encéfalo/diagnóstico por imagem , Futebol Americano/lesões , Neuroimagem , Acelerometria , Circulação Cerebrovascular/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Fibras Nervosas/patologia , Vias Neurais/diagnóstico por imagem , Estações do Ano , Universidades , Adulto Jovem
19.
Brain Imaging Behav ; 11(1): 98-112, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-26809358

RESUMO

As participation in women's soccer continues to grow and the longevity of female athletes' careers continues to increase, prevention and care for mTBI in women's soccer has become a major concern for female athletes since the long-term risks associated with a history of mTBI are well documented. Among women's sports, soccer exhibits among the highest concussion rates, on par with those of men's football at the collegiate level. Head impact monitoring technology has revealed that "concussive hits" occurring directly before symptomatic injury are not predictive of mTBI, suggesting that the cumulative effect of repetitive head impacts experienced by collision sport athletes should be assessed. Neuroimaging biomarkers have proven to be valuable in detecting brain changes that occur before neurocognitive symptoms in collision sport athletes. Quantifying the relationship between changes in these biomarkers and head impacts experienced by female soccer athletes may prove valuable to developing preventative measures for mTBI. This study paired functional magnetic resonance imaging with head impact monitoring to track cerebrovascular reactivity changes throughout a season and to test whether the observed changes could be attributed to mechanical loading experienced by female athletes participating in high school soccer. Marked cerebrovascular reactivity changes were observed in female soccer athletes, relative both to non-collision sport control measures and pre-season measures and were localized to fronto-temporal aspects of the brain. These changes persisted 4-5 months after the season ended and recovered by 8 months after the season. Segregation of the total soccer cohort into cumulative loading groups revealed that population-level changes were driven by athletes experiencing high cumulative loads, although athletes experiencing lower cumulative loads still contributed to group changes. The results of this study imply a non-linear relationship between cumulative loading and cerebrovascular changes with a threshold, above which the risk, of injury likely increases significantly.


Assuntos
Traumatismos em Atletas/fisiopatologia , Lesões Encefálicas Traumáticas/etiologia , Lesões Encefálicas Traumáticas/fisiopatologia , Encéfalo/fisiopatologia , Futebol/lesões , Adolescente , Atletas , Traumatismos em Atletas/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Estudos de Coortes , Feminino , Humanos , Imagem por Ressonância Magnética , Estudantes , Fatores de Tempo
20.
Obesity (Silver Spring) ; 24(10): 2057-63, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27542906

RESUMO

OBJECTIVE: The brain's reward system influences ingestive behavior and subsequently obesity risk. Functional magnetic resonance imaging (fMRI) is a common method for investigating brain reward function. This study sought to assess the reproducibility of fasting-state brain responses to visual food stimuli using BOLD fMRI. METHODS: A priori brain regions of interest included bilateral insula, amygdala, orbitofrontal cortex, caudate, and putamen. Fasting-state fMRI and appetite assessments were completed by 28 women (n = 16) and men (n = 12) with overweight or obesity on 2 days. Reproducibility was assessed by comparing mean fasting-state brain responses and measuring test-retest reliability of these responses on the two testing days. RESULTS: Mean fasting-state brain responses on day 2 were reduced compared with day 1 in the left insula and right amygdala, but mean day 1 and day 2 responses were not different in the other regions of interest. With the exception of the left orbitofrontal cortex response (fair reliability), test-retest reliabilities of brain responses were poor or unreliable. CONCLUSIONS: fMRI-measured responses to visual food cues in adults with overweight or obesity show relatively good mean-level reproducibility but considerable within-subject variability. Poor test-retest reliability reduces the likelihood of observing true correlations and increases the necessary sample sizes for studies.


Assuntos
Regulação do Apetite/fisiologia , Comportamento de Escolha/fisiologia , Comportamento Alimentar/fisiologia , Preferências Alimentares/psicologia , Obesidade/fisiopatologia , Adulto , Tonsila do Cerebelo/fisiologia , Apetite/fisiologia , Sinais (Psicologia) , Jejum/fisiologia , Feminino , Lobo Frontal/fisiopatologia , Humanos , Masculino , Estimulação Luminosa/métodos , Reprodutibilidade dos Testes , Recompensa , Adulto Jovem
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