Characterizing head impact exposure in youth female soccer with a custom-instrumented mouthpiece.

While many research efforts have focused on head impact exposure in professional soccer, there have been few studies characterizing exposure at the youth level. The aim of this study is to evaluate a new instrumentation approach and collect some of the first head impact exposure data for youth female soccer players. Athletes were instrumented with custom-fit mouthpieces that measure head impacts. Detailed video analysis was conducted to identify characteristics describing impact source (e.g., kick, header, throw). A total of 763 verified head impacts were collected over 23 practices and 8 games from 7 athletes. The median peak linear accelerations, rotational velocities, and rotational accelerations of all impacts were 9.4 g, 4.1 rad/s, and 689 rad/s2, respectively. Pairwise comparisons resulted in statistically significant differences in kinematics by impact source. Headers following a kicked ball had the highest accelerations and velocity when compared to headers from thrown or another header.

Cerebral blood flow in children and adolescents several years after concussion.

OBJECTIVES: The long-term effects of concussion in youth remain poorly understood. The objective of this study was to determine the association between history of concussion and cerebral blood flow (CBF) in youth. METHODS: A total of 53 children and adolescents with a history of concussion (n = 37) or orthopaedic injury (OI; n = 16) were considered. Measures included pseudo-continuous arterial spin labelling magnetic resonance imaging to quantify CBF, post-concussion symptoms, psychological symptoms, and cognitive testing. RESULTS: Participants (mean age: 14.4 years, 95% CI = 13.8-15.4, range = 8-19) were on average 2.7 years (95% CI = 2.2-3.1) post-injury. Youth with a history of concussion had higher parent-reported physical, cognitive, anxiety, and depression symptoms than children with OI, but the groups did not differ on self-reported symptoms (post-concussive or psychological) or cognitive testing. Global CBF did not differ between groups. Regional CBF analyses suggested that youth with a history of concussion had hypoperfusion in posterior and inferior regions and hyperperfusion in anterior/frontal/temporal regions as compared to those with OI. However, neither global nor regional CBF were significantly associated with demographics, pre-injury functioning, number of concussions, time since injury, post-concussive symptoms, psychological symptoms, or cognitive abilities. CONCLUSIONS: Youth with a history of concussion demonstrate differences in regional CBF (not global CBF), but without clear clinical expression.

Modeling of inflicted head injury by shaking trauma in children: what can we learn? : Part II: A systematic review of mathematical and physical models.

Various types of complex biomechanical models have been published in the literature to better understand processes related to inflicted head injury by shaking trauma (IHI-ST) in infants. In this systematic review, a comprehensive overview of these models is provided. A systematic review was performed in MEDLINE and Scopus for articles using physical (e.g. dolls) and mathematical (e.g. computer simulations) biomechanical models for IHI-ST. After deduplication, the studies were independently screened by two researchers using PRISMA methodology and data extracted from the papers is represented in a "7-steps description", addressing the different processes occurring during IHI-ST. Eleven papers on physical models and 23 papers on mathematical models were included after the selection process. In both categories, some models focus on describing gross head kinematics during IHI-ST events, while others address the behavior of internal head- and eye structures in various levels of detail. In virtually all physical and mathematical models analyzed, injury thresholds are derived from scaled non-infant data. Studies focusing on head kinematics often use injury thresholds derived from impact studies. It remains unclear to what extent these thresholds reflect the failure thresholds of infant biological material. Future research should therefore focus on investigating failure thresholds of infant biological material as well as on possible alternative injury mechanism and alternative injury criteria for IHI-ST.

Visual pursuit of one's own face in disorders of consciousness: a quantitative analysis.

BACKGROUND: Eye behaviour is important to distinguish minimally conscious state (MCS) from vegetative state (VS). OBJECTIVE: To search for conditions most suitable to characterize patients in MCS and in VS on quantitative assessment of visual tracking. DESIGN: This is a cross-sectional study. PARTICIPANTS: In total, 20 patients in VS, 13 in MCS plus and 11 in MCS minus participated in this study. SETTING: Neurorehabilitation Unit. METHODS: Evaluation of eye behaviour was performed by infrared system; stimuli were represented by a red circle, a picture of a patient's own face and a picture of an unfamiliar face, slowly moving on a personal computer (PC) monitor. Visual tracking on the horizontal and vertical axes was compared. MAIN OUTCOME MEASURES: The main outcome measures were proportion of on-target fixations and mean fixation duration. RESULTS: The proportion of on-target fixations differed as a function of the stimulus in patients in MCS plus but not in other groups. Own face and unfamiliar face elicited a similar proportion of on-target fixations. Tracking along the horizontal axis was more accurate than that along the vertical axis in patients in both MCS plus and MCS minus. Fixation duration did not differ among the three groups. CONCLUSIONS: Horizontal visual tracking of salient stimuli seems particularly suitable for eliciting on-target fixations. Quantitative assessment of visual tracking can complement clinical evaluation for reducing diagnostic uncertainty between patients in MCS or VS.

Clinical Signs of Basilar Skull Fracture and Their Predictive Value in Diagnosis of This Injury.

Although clinical signs for the diagnosis of basilar skull fracture (BSF) are ambiguous, they are widely used to make decisions on initial interventions involving trauma patients. We aimed to assess the performance of early and late (within 48 hr posttrauma) signs for BSF diagnosis and to verify the correlation between the presence of these signs and head injury severity. We conducted a prospectively designed follow-up study at a referral hospital for trauma care in Sao Paulo, Brazil, and performed structured observations for 48 hr post-blunt head injury in patients aged 12 years or older. The following signs of BSF were considered: raccoon eyes, Battle's sign, otorrhea, and rhinorrhea. Among the 136 enrolled patients (85.3% male; mean age 40 ± 21.4 years), 28 patients (20.6%) had BSF. The clinical signs for the early or late detection of BSF had low accuracy (55.9% vs. 43.4%), specificity (52.8% vs. 30.5%), and positive predictive value (25.7% vs. 27.1%). However, the presence of these signs was correlated to head injury severity, indicated by the Glasgow Coma Scale (p = .041) and Maximum Abbreviated Injury Scale-Head region (p = .002). In view of the low accuracy of these signs, resulting low clinical value of their presence, and their high sensitivity in the late stage, the study results contraindicate the value of BSF signs for making decisions about using the nasal route for the introduction of catheters and tubes in initial trauma care.

Increased prognostic accuracy of TBI when a brain electrical activity biomarker is added to loss of consciousness (LOC).

BACKGROUND: Extremely high accuracy for predicting CT+ traumatic brain injury (TBI) using a quantitative EEG (QEEG) based multivariate classification algorithm was demonstrated in an independent validation trial, in Emergency Department (ED) patients, using an easy to use handheld device. This study compares the predictive power using that algorithm (which includes LOC and amnesia), to the predictive power of LOC alone or LOC plus traumatic amnesia. PARTICIPANTS: ED patients 18-85years presenting within 72h of closed head injury, with GSC 12-15, were study candidates. 680 patients with known absence or presence of LOC were enrolled (145 CT+ and 535 CT- patients). METHODS: 5-10min of eyes closed EEG was acquired using the Ahead 300 handheld device, from frontal and frontotemporal regions. The same classification algorithm methodology was used for both the EEG based and the LOC based algorithms. Predictive power was evaluated using area under the ROC curve (AUC) and odds ratios. RESULTS: The QEEG based classification algorithm demonstrated significant improvement in predictive power compared with LOC alone, both in improved AUC (83% improvement) and odds ratio (increase from 4.65 to 16.22). Adding RGA and/or PTA to LOC was not improved over LOC alone. CONCLUSIONS: Rapid triage of TBI relies on strong initial predictors. Addition of an electrophysiological based marker was shown to outperform report of LOC alone or LOC plus amnesia, in determining risk of an intracranial bleed. In addition, ease of use at point-of-care, non-invasive, and rapid result using such technology suggests significant value added to standard clinical prediction.

Association of Cerebral Venous Thrombosis and Intracranial Hypotension: Review of 3 Cases.

Cerebral venous thrombosis is a rare complication of intracranial hypotension. We describe 3 cases in which this phenomenon occurred, as a result of a lumbar puncture or due to a spontaneous cerebrospinal fluid leak. We emphasize the importance of early detection of the intracranial hypotension syndrome, the most common clinical manifestation being orthostatic headache. It is not an innocent condition as it is associated with other potential complications such as subdural hygroma/hematoma, cranial nerve palsies, cerebellar tonsillar descent, and even brainstem manifestations. Any change in the typical features of the syndrome should lead to further investigation. Repeat cerebral imaging is important in that situation, including ruling out cerebral venous thrombosis.

Closed head injury in an age-related Alzheimer mouse model leads to an altered neuroinflammatory response and persistent cognitive impairment.

Epidemiological studies have associated increased risk of Alzheimer's disease (AD)-related clinical symptoms with a medical history of head injury. Currently, little is known about pathophysiology mechanisms linked to this association. Persistent neuroinflammation is one outcome observed in patients after a single head injury. Neuroinflammation is also present early in relevant brain regions during AD pathology progression. In addition, previous mechanistic studies in animal models link neuroinflammation as a contributor to neuropathology and cognitive impairment in traumatic brain injury (TBI) or AD-related models. Therefore, we explored the potential interplay of neuroinflammatory responses in TBI and AD by analysis of the temporal neuroinflammatory changes after TBI in an AD model, the APP/PS1 knock-in (KI) mouse. Discrete temporal aspects of astrocyte, cytokine, and chemokine responses in the injured KI mice were delayed compared with the injured wild-type mice, with a peak neuroinflammatory response in the injured KI mice occurring at 7 d after injury. The neuroinflammatory responses were more persistent in the injured KI mice, leading to a chronic neuroinflammation. At late time points after injury, KI mice exhibited a significant impairment in radial arm water maze performance compared with sham KI mice or injured wild-type mice. Intervention with a small-molecule experimental therapeutic (MW151) that selectively attenuates proinflammatory cytokine production yielded improved cognitive behavior outcomes, consistent with a link between neuroinflammatory responses and altered risk for AD-associated pathology changes with head injury.

Biomechanical assessment of the injury risk of stomping.

Forensic case work as well as literature shows that severe head injuries, e.g., with basilar fractures and cerebral hemorrhages due to stomps can be seen; however, there is no data basis concerning contact forces and potential influencing factors. The objective of this work was to generate a data basis of contact forces in stomping by performing experimental measurements and subsequent statistical analyses. Fifty-five volunteers participated in the present study. Each participant performed several stomps onto force plates with sturdy/soft footwear as well as with/without an elastic layer imitating the scalp. Ground reaction forces induced by jumps were also measured for sturdy and soft footwear. The results show statistically significant dependencies between maximum ground reaction forces and body weight and body height. A statistically significant influence of footwear on stomping force could only be found in tests with an elastic layer and in the jumping setup. Mean maximum stomping forces for the female volunteers were between 4694 and 5970 N; male volunteers were able to produce mean peak stomping forces between 8494 and 9016 N. Jumping forces were approximately twice the stomping forces for both male and female test persons. Regardless of footwear and gender, it can be claimed that a forceful stomp or jump to someone's head supported on the ground can cause facial and skull fractures. Thus, forceful stomps or jumps to someone's head can cause potential fatal injuries independent of footwear, gender, or fitness level.

Mixture Models for Estimating Maximum Blood Flow Velocity.

OBJECTIVES: A gaussian mixture model (GMM) was recently developed for estimating the probability density function of blood flow velocity measured with transcranial Doppler ultrasound data. In turn, the quantiles of the probability density function allow one to construct estimators of the "maximum" blood flow velocity. However, GMMs assume gaussianity, a feature that is not omnipresent in observed data. The objective of this work was to develop mixture models that do not invoke the gaussian assumption. METHODS: Here, GMMs were extended to a skewed GMM and a nongaussian kernel mixture model. All models were developed on data from 59 patients with closed head injuries from multiple hospitals in the United States, with ages ranging from 13 to 81 years and Glasgow Coma Scale scores ranging from 3 to 11. The models were assessed in terms of the log likelihood (a goodness-of-fit measure) and via visual comparison with the underlying spectrograms. RESULTS: Among the models examined, the skewed GMM showed a significantly (P< .05) higher log likelihood for 56 of the 59 patients and produced maximum flow velocity estimates consistent with the observed spectrograms for all patients. Kernel mixture models are generally less "robust" in that their quality is inconsistent across patients. CONCLUSIONS: Among the models examined, it was found that the skewed GMM provided a better model of the data both in terms of the quality of the fit and in terms of visual comparison of the underlying spectrogram and the estimated maximum blood flow velocity. Nongaussian mixture models have potential for even higher-quality assessment of blood flow, but further development is called for.

Development of a skull/brain model for military wound ballistics studies.

Reports on penetrating ballistic head injuries in the literature are dominated by case studies of suicides; the penetrating ammunition usually being .22 rimfire or shotgun. The dominating cause of injuries in modern warfare is fragmentation and hence, this is the primary threat that military helmets protect the brain from. When helmets are perforated, this is usually by bullets. In combat, 20% of penetrating injuries occur to the head and its wounding accounts for 50% of combat deaths. A number of head simulants are described in the academic literature, in ballistic test methods for helmets (including measurement of behind helmet blunt trauma, BHBT) and in the 'open' and 'closed' government literature of several nations. The majority of these models are not anatomically correct and are not assessed with high-velocity rifle ammunition. In this article, an anatomically correct 'skull' (manufactured from polyurethane) and 'brain' (manufactured from 10%, by mass, gelatine) model for use in military wound ballistic studies is described. Filling the cranium completely with gelatine resulted in a similar 'skull' fracture pattern as an anatomically correct 'brain' combined with a representation of cerebrospinal fluid. In particular, posterior cranial fossa and occipital fractures and brain ejection were observed. This pattern of injury compared favourably to reported case studies of actual incidents in the literature.

Does acute TBI-related sleep disturbance predict subsequent neuropsychiatric disturbances?

PRIMARY OBJECTIVE: To determine whether sleep disturbance in the acute post-traumatic brain injury (TBI) period predicts symptoms of depression, anxiety or apathy measured 6 and 12 months after TBI. RESEARCH DESIGN: Longitudinal, observational study. METHODS AND PROCEDURES: First time closed-head injury patients (n = 101) were recruited and evaluated within 3 months of injury and followed longitudinally, with psychiatric evaluations at 6 and 12 months post-injury. Pre- and post-injury sleep disturbances were measured via the Medical Outcome Scale (MOS) for Sleep. Subjects were also assessed for anxiety, depression, apathy, medical comorbidity and severity of TBI. MAIN OUTCOMES AND RESULTS: Sleep disturbance in the acute TBI period was associated with increased symptoms of depression, anxiety and apathy 12 months post-injury. CONCLUSIONS: Sleep disturbances experienced soon after trauma (i.e. <3 months after injury) predicted neuropsychiatric symptoms 1 year after injury, raising two important clinical questions: (1) Is sleep disturbance soon after trauma a prognostic marker of subsequent neuropsychiatric symptoms? and (2) Can early treatment of sleep disturbance during the post-TBI period reduce subsequent development of neuropsychiatric symptoms? Future studies with larger sample sizes and appropriate control groups could help to answer these questions, using evidence-based methods for evaluating and treating sleep disturbances.

Early postinjury exercise reverses memory deficits and retards the progression of closed-head injury in mice.

Closed-head injury (CHI) usually involves both physical damage of neurons and neuroinflammation. Although exercise promotes neuronal repair and suppresses neuroinflammation, CHI patients currently often remain resting during the post-traumatic period. This study aimed to investigate whether and how postinjury exercise benefited the brain structure and function in mice after CHI. Closed-head injury immediately caused an elevated neurological severity score, with rapid loss of object recognition memory, followed by progressive location-dependent brain damage (neuronal loss and activation of microglia in the cortex and hippocampus). An early exercise protocol at moderate intensity (starting 2 days postimpact and lasting for 7 or 14 days) effectively restored the object recognition memory and prevented the progressive neuronal loss and activation of microglia. However, if the exercise started 9 days postimpact, it was unable to recover recognition memory deficits. In parallel, early exercise intervention drastically promoted neurite regeneration, while late exercise intervention was much less effective. We also tested the possible involvement of brain-derived neurotrophic factor (BDNF) and mitogen-activated protein kinase phosphatase-1 (MKP-1) in the exercise-induced beneficial effects. Exercise gradually restored the impact-abolished hippocampal expression of BDNF and MPK-1, while oral administration of triptolide (a synthesis inhibitor of MKP-1 and an antagonist of nuclear factor-B) before each bout of exercise blocked the restorative effects of exercise on MKP-1 and recognition memory, as well as the exercise-induced retardation of neuronal loss. Although triptolide treatment alone inhibited activation of microglia and maintained neuronal numbers, it did not recover the injury-hampered recognition memory. Overall, moderate exercise shortly after CHI reversed the deficits in recognition memory and prevented the progression of brain injury.

Infrared pupillometry. Basic principles and their application in the non-invasive monitoring of neurocritical patients.

INTRODUCTION: Pupil assessment is a fundamental part of the neurological examination. Size and reactivity to light of each pupil should be recorded periodically since changes in these parameters may represent the only detectable sign of neurological deterioration in some patients. However, there is great intraobserver and interobserver variability in pupil examination due to the influence of many factors, such as the difference in ambient lighting, the visual acuity and experience of the examiner, the intensity of the luminous stimulus, and the method used to direct this stimulus. In recent years, digital cameras have incorporated infrared devices allowing the development of user-friendly portable devices that permit repeated, non-invasive examinations of pupil size and its reactivity to light with an objective, accessible and inexpensive method. DEVELOPMENT: The purpose of this review is to describe the fundamentals of infrared pupillometry and discuss potential applications in the monitoring of neurocritical patients. We also present some recommendations in the routine assessment of pupils in neurocritical patients. CONCLUSIONS: The possibility of evaluating the changes in pupil reactivity in an early, objective and almost continuous way provides a new non-invasive monitoring method. This method could improve the predictive factor of neurological deterioration and the bedside monitoring of the neurological state of the patient, avoiding unnecessary examinations and enabling early therapeutic intervention.

Serum S100B determination in the management of pediatric mild traumatic brain injury.

BACKGROUND: The place of serum S100B measurement in mild traumatic brain injury (mTBI) management is still controversial. Our prospective study aimed to evaluate its utility in the largest child cohort described to date. METHODS: Children younger than 16 years presenting at a pediatric emergency department within 3 h after TBI were enrolled prospectively for blood sampling to determine serum S100B concentrations. The following information was collected: TBI severity determined by using the Masters classification [1: minimal or Glasgow Coma Scale (GCS) 15, 2: mild or GCS 13-15, and 3: severe or GCS <13]; whether hospitalized or not; good or bad clinical evolution (CE); whether cranial computed tomography (CCT) was prescribed; and related presence (CCT+) or absence (CCT-) of lesions. RESULTS: For the 446 children enrolled, the median concentrations of S100B were 0.21, 0.31, and 0.44 µg/L in Masters groups 1, 2, and 3, respectively, with a statistically significant difference between these groups (P < 0.05). In Masters group 2, 65 CCT scans were carried out. Measurement of S100B identified patients as CCT+ with 100% (95% CI 85-100) sensitivity and 33% (95% CI 20-50) specificity. Of the 424 children scored Masters 1 or 2, 21 presented "bad CE." S100B identified bad CE patients with 100% (95% CI 84-100) sensitivity and 36% (95% CI 31-41) specificity. Of the 242 children hospitalized, 81 presented an S100B concentration within the reference interval. CONCLUSIONS: Serum S100B determination during the first 3 h of management of children with mTBI has the potential to reduce the number of CCT scans, thereby avoiding unnecessary irradiation, and to save hospitalization costs.

Sentence comprehension following moderate closed head injury in adults.

The current study explores sentence comprehension impairments among adults following moderate closed head injury. It was hypothesized that if the factor of syntactic complexity significantly affects sentence comprehension in these patients, it would testify to the existence of syntactic processing deficit along with working-memory problems. Thirty-six adults (18 closed head injury patients and 18 healthy controls matched in age, gender, and IQ) participated in the study. A picture-sentence matching task together with various tests for memory, language, and reading abilities were used to explore whether sentence comprehension impairments exist as a result of a deficit in syntactic processing or of working-memory dysfunction. Results indicate significant impairment in sentence comprehension among adults with closed head injury compared with their non-head-injured peers. Results also reveal that closed head injury patients demonstrate considerable decline in working memory, short-term memory, and semantic knowledge. Analysis of the results shows that memory impairment and syntactic complexity contribute significantly to sentence comprehension difficulties in closed head injury patients. At the same time, the presentation mode (spoken or written language) was found to have no effect on comprehension among adults with closed head injury, and their reading abilities appear to be relatively intact.

Finite-element study of cerebrospinal fluid in mitigating closed head injuries.

The mechanism of cerebrospinal fluid in mitigating closed head injuries caused by mild impacts was investigated by finite-element modeling. Three biomechanical models were constructed. In these models, cerebrospinal fluid was considered as a soft solid material, an inviscid fluid without intracranial pressure, and an inviscid fluid with normal intracranial pressure, respectively, while other conditions such as the finite-element mesh, the impact, and the boundary conditions were kept the same. The recently developed nearest nodes finite-element method was adopted to deal with large deformations in brain tissue. Results obtained from the numerical studies showed that cerebrospinal fluid was able to remarkably reduce the maximum peak strains, especially the shear strains induced by impacts and transmitted to the brain. Cerebrospinal fluid with intracranial pressure was able to further buffer relative oscillations between the skull and the brain.

[Criteria of limitation of vital functions in remote consequences of closed craniocerebral trauma].

On the basis of international classification of functioning, limitations of vital functions and health (MKF) were conducted inspections patients with the remote consequences of the closed craniocerebral trauma. All of patients passed a standard clinical neurological inspection and testing with a help MKF. It is well-proven that adaptation MKF allows to apply it at expert diagnostics, and also to estimate rehabilitation potential and efficiency of leadthrough of rehabilitation measures at patients with the remote consequences of the closed craniocerebral trauma.

[Mechanisms of damage of internal ear capsules labyrinths at head injury, caused by non-lethal kinetic weapon].

Structural, physical, chemical and micromechanical properties capsules labyrinths of an internal ear are studied at influence of the shock wave caused by wound of a head by not lethal kinetic weapon. It is established, that under the influence of a shock wave in bone plates capsules labyrinths processes remodeling, and accompanied osteolysis amplify. Hydroxyapatites capsules labyrinths tests polymorphic phase transitions and depending on an initial condition is exposed amorphizationor increases the crystallinity. As a result of change of micromechanical properties in capsules labyrinths there are cracks, ruptures matrix and bone cavities.