Traumatic brain injury (TBI) is a serious public health problem. Even injuries classified as mild, the most common, can result in persistent neurobehavioural impairment. Diffuse axonal injury is a common finding after TBI, and is presumed to contribute to outcomes, but may not always be apparent using standard neuroimaging. Diffusion tensor imaging (DTI) is a more recent method of assessing axonal integrity in vivo. The primary objective of the current investigation was to characterize white matter integrity utilizing DTI across the spectrum of chronic TBI of all severities. A secondary objective was to examine the relationship between white matter integrity and cognition. Twenty mild, 17 moderate to severe TBI and 18 controls underwent DTI and neuropsychological testing. Fractional anisotropy, axial diffusivity and radial diffusivity were calculated from the DTI data. Fractional anisotropy was the primary measure of white matter integrity. Region of interest analysis included anterior and posterior corona radiata, cortico-spinal tracts, cingulum fibre bundles, external capsule, forceps minor and major, genu, body and splenium of the corpus callosum, inferior fronto-occipital fasciculus, superior longitudinal fasciculus and sagittal stratum. Cognitive domain scores were calculated from executive, attention and memory testing. Decreased fractional anisotropy was found in all 13 regions of interest for the moderate to severe TBI group, but only in the cortico-spinal tract, sagittal stratum and superior longitudinal fasciculus for the mild TBI group. White Matter Load (a measure of the total number of regions with reduced FA) was negatively correlated with all cognitive domains. Analysis of radial and axial diffusivity values suggested that all severities of TBI can result in a degree of axonal damage, while irreversible myelin damage was only apparent for moderate to severe TBI. The present data emphasize that white matter changes exist on a spectrum, including mild TBI. An index of global white matter neuropathology (White Matter Load) was related to cognitive function, such that greater white matter pathology predicted greater cognitive deficits. Mechanistically, mild TBI white matter changes may be primarily due to axonal damage as opposed to myelin damage. The more severe injuries impact both. DTI provides an objective means for determining the relationship of cognitive deficits to TBI, even in cases where the injury was sustained years prior to the evaluation.

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White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study

OBJECTIVE: This report presents the most current (2005) nationally representative data on visits to hospital emergency departments (ED) in the United States. Statistics are presented on selected hospital, patient, and visit characteristics. Selected trends in ED utilization from 1995 through 2005 are also presented. METHODS: Data are from the 2005 National Hospital Ambulatory Medical Care Survey (NHAMCS), the longest continuously running nationally representative survey of hospital ED and outpatient department (OPD) utilization. The NHAMCS collects data on visits to emergency and outpatient departments of nonfederal, short-stay, and general hospitals in the United States. Sample data are weighted to produce annual national estimates. RESULTS: During 2005, an estimated 115.3 million visits were made to hospital EDs, about 39.6 visits per 100 persons. This represents on average roughly 30,000 visits per ED in 2005, a 31 percent increase over 1995 (23,000). Visit rates have shown an increasing trend since 1995 for persons 22-49 years of age, 50-64 years of age, and 65 years of age and over. In 2005, about 0.5 million (0.4 percent) of visits were made by homeless individuals. Nearly 18 million patients arrived by ambulance (15.5 percent). At 1.9 percent of visits, the patient had been discharged from the hospital within the previous 7 days. Abdominal pain, chest pain, fever, and cough were the leading patient complaints, accounting for nearly one-fifth of all visits. Abdominal pain was the leading illness-related diagnosis at ED visits. There were an estimated 41.9 million injury-related visits or 14.4 visits per 100 persons. Diagnostic and screening services were provided at 71.1 percent of visits, and procedures were performed at 47.3 percent of visits. Medications were either given in the ED or prescribed at discharge at 76.7 percent of visits, resulting in 204.9 million drug mentions. On average, patients spent 56.3 minutes waiting to see a physician, and 3.3 hours for the full duration of their ED visit. About 12 percent of ED visits resulted in hospital admission. The average total length of stay for those admitted was 5.2 days, and the leading principal hospital discharge diagnosis was nonischemic heart disease. Language: en

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National Hospital Ambulatory Medical Care Survey: 2005 emergency department summary.

Summary Background Traumatic brain injury (TBI) is the leading cause of long-term disability in children and young adults worldwide. However, accurate information about its incidence does not exist. We aimed to estimate the burden of TBI in rural and urban populations in New Zealand across all ages and TBI severities. Methods We did a population-based incidence study in an urban (Hamilton) and rural (Waikato District) population in New Zealand. We registered all cases of TBI (admitted to hospital or not, fatal or non-fatal) that occurred in the population between March 1, 2010, and Feb 28, 2011, using multiple overlapping sources of information. We calculated incidence per 100 000 person-years with 95% CIs using a Poisson distribution. We calculated rate ratios [RRs] to compare the age-standardised rates between sex, ethnicity, and residency (urban, rural) groups. We used direct standardisation to age-standardise the rates to the world population. Results The total incidence of TBI per 100 000 person-years was 790 cases (95% CI 749–832); incidence per 100 000 person-years of mild TBI was 749 cases (709–790) and of moderate to severe TBI was 41 cases (31–51). Children (aged 0–14 years) and adolescents and young adults (aged 15–34 years) constituted almost 70% of all TBI cases. TBI affected boys and men more than women and girls (RR 1·77, 95% CI 1·58–1·97). Most TBI cases were due to falls (38% [516 of 1369]), mechanical forces (21% [288 of 1369]), transport accidents (20% [277 of 1369]), and assaults (17% [228 of 1369]). Compared with people of European origin, Maori people had a greater risk of mild TBI (RR 1·23, 95% CI 1·08–1·39). Incidence of moderate to severe TBI in the rural population (73 per 100 000 person-years [95% CI 50–107) was almost 2·5 times greater than in the urban population (31 per 100 000 person-years [23–42]). Interpretation Our findings suggest that the incidence of TBI, especially mild TBI, in New Zealand is far greater than would be estimated from the findings of previous studies done in other high-income countries. Our age-specific and residency-specific data for TBI incidence overall and by mechanism of injury should be considered when planning prevention and TBI care services. Funding Health Research Council of New Zealand.

Incidence of traumatic brain injury in New Zealand: a population-based study

The goal of the current investigation was to detect clinically important axonal damage in cerebral white matter after mild traumatic brain injury (TBI) using diffusion tensor imaging (DTI). To this end, we evaluated a prospective, pilot study of six subjects with isolated mild TBI and six matched orthopedic controls. All subjects underwent DTI scanning, post-concussive symptom (PCS) assessment, and neurobehavioral testing within 72 h of injury. Fractional anisotropy (FA) and trace values in white matter voxels of whole brain and five preslected regions of interest (ROI) were compared in mild TBI and control subjects using a quantile approach. In addition, whole brain images were analyzed using voxel-based morphometry. All subjects underwent quality of life and repeat PCS assessment at 1 month. Whole brain images revealed significantly lower 1st percentile trace values (mean 0.465 vs. 0.488, p = 0.049) among mild TBI subjects. These trace values correlated with PCS scores at both 72 h (r = −0.57, p = 0.05)...

Diffusion tensor imaging detects clinically important axonal damage after mild traumatic brain injury: a pilot study.

Context: Evidence suggests that athletes engaging in high-intensity activities after concussion have more difficulties with cognitive recovery. Objective: To examine the role postinjury ac...

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Concussion in sports: postconcussive activity levels, symptoms, and neurocognitive performance.

Primary objective: To determine the incidence and epidemiology of emergency department (ED)-attended mild traumatic brain injury (mTBI) in the US.Research design: Secondary analysis of ED visits for mTBI in the National Hospital Ambulatory Medical Care Survey for 1998–2000.Methods and procedures: MTBI defined by International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes for ‘skull fracture’, ‘concussion’, ‘intracranial injury of unspecified nature’ and ‘head injury, unspecified’.Main outcome and results: The average incidence of mTBI was 503.1/100 000, with peaks among males (590/100 000), American Indians/Alaska Natives (1,026/100 000) and those <5 years of age (1,115.2/100 000). MTBI incidence was highest in the Midwest region (578.4/10 000) and in non-urban areas (530.9/100 000) of the US. Bicycles and sports accounted for 26.4% of mTBI in the 5–14 age group.Conclusions: The national burden of mTBI is significant and the incidence higher than that reported by others....

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Mild traumatic brain injury in the United States, 1998-2000

OBJECTIVES: To identify racial, ethnic, and gender disparities in the emergency department (ED) care for mild traumatic brain injury (mTBI). METHODS: A secondary analysis of ED visits in the National Hospital Ambulatory Medical Care Survey for the years 1998 through 2000 was performed. Cases of mTBI were identified using ICD-9 codes 800.0, 800.5, 850.9, 801.5, 803.0, 803.5, 804.0, 804.5, 850.0, 850.1, 850.5, 850.9, 854.0, and 959.01. ED care variables related to imaging, procedures, treatments, and disposition were analyzed along racial, ethnic, and gender categories. The relationship between race, ethnicity, and selected ED care variables was analyzed using multivariate logistic regression with control for associated injuries, geographic region, and insurance type. RESULTS: The incidence of mTBI was highest among men (590/100,000), Native Americans/Alaska Natives (1026.2/100,000), and non-Hispanics (391.1/100,000). After controlling for important confounders, Hispanics were more likely than non-Hispanics to receive a nasogastric tube (OR, 6.36; 95% CI = 1.2 to 33.6); nonwhites were more likely to receive ED care by a resident (OR, 3.09; 95% CI = 1.9 to 5.0) and less likely to be sent back to the referring physician after ED discharge (OR, 0.47; 95% CI = 0.3 to 0.9). Men and women received equivalent ED care. CONCLUSIONS: There are significant racial and ethnic but not gender disparities in ED care for mTBI. The causes of these disparities and the relationship between these disparities and post-mTBI outcome need to be examined. Language: en

https://onlinelibrary.wiley.com/doi/pdf/10.1197/S1069-6563%2803%2900491-3

Jason McClung

Papers

Mild traumatic brain injury in the United States, 1998-2000

Ethnic and racial disparities in emergency department care for mild traumatic brain injury.