Gaining a better understanding of the factors that affect the likelihood of a vehicle crash has been an area of research focus for many decades. However, in the absence of detailed driving data that would help improve the identification of cause and effect relationships with individual vehicle crashes, most researchers have addressed this problem by framing it in terms of understanding the factors that affect the frequency of crashes - the number of crashes occurring in some geographical space (usually a roadway segment or intersection) over some specified time period. This paper provides a detailed review of the key issues associated with crash-frequency data as well as the strengths and weaknesses of the various methodological approaches that researchers have used to address these problems. While the steady march of methodological innovation (including recent applications of random parameter and finite mixture models) has substantially improved our understanding of the factors that affect crash-frequencies, it is the prospect of combining evolving methodologies with far more detailed vehicle crash data that holds the greatest promise for the future.

http://ceprofs.tamu.edu/dlord/Papers/Lord-Mannering_Review.pdf

The statistical analysis of crash-frequency data: A review and assessment of methodological alternatives

We searched the literature on the epidemiology, diagnosis, prognosis, treatment and costs of mild traumatic brain injury. Of 428 studies related to prognosis after mild traumatic brain injury, 120 (28%) were accepted after critical review. These comprise our best-evidence synthesis on prognosis after mild traumatic brain injury. There was consistent and methodologically sound evidence that children's prognosis after mild traumatic brain injury is good, with quick resolution of symptoms and little evidence of residual cognitive, behavioural or academic deficits. For adults, cognitive deficits and symptoms are common in the acute stage, and the majority of studies report recovery for most within 3-12 months. Where symptoms persist, compensation/litigation is a factor, but there is little consistent evidence for other predictors. The literature on this area is of varying quality and causal inferences are often mistakenly drawn from cross-sectional studies.

/pdf/prognosis-for-mild-traumatic-brain-injury-results-of-the-who-3kurycsfa2.pdf

Prognosis for mild traumatic brain injury: results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury.

Summary Background. The world’s literature on traumatic brain injury (TBI) grows annually including new reports on epidemiologic findings from many regions. With the wide variety of reports emphasizing various factors it is useful to compile these findings, hence the objective of this report. Thus, we describe epidemiological factors from European studies largely published in the last 20 years. Method. The Medline was searched for TBI related articles from about 1980 to 2003 including terms such as ‘‘epidemiology’’, ‘‘head injury’’, ‘‘brain injury’’ and others. From the research reports identified, we checked references for additional relevant reports and from those reports we abstracted data on TBI incidence, severity, external cause, gender, mortality, prevalence, cost and related factors. Results. Twenty three European reports met inclusion criteria and included findings from national studies from Denmark, Sweden, Finland, Portugal, Germany, and from regions within Norway, Sweden, Italy, Switzerland, Spain, Denmark, Ireland, the U.K. and France. An aggregate hospitalized plus fatal TBI incidence rate of about 235 per 100,000 was derived. Prevalence rate data were not reported from any European country. An average mortality rate of about 15 per 100,000 and case fatality rate of about 11 per 100 were derived. The TBI severity ratio of hospitalized patients was about 22:1.5:1 for mild vs. moderate vs. severe cases, respectively. The percentages of TBI from external causes varied considerably and several reports reported an association of alcohol use with TBI. Outcome or disability findings were mixed and inconsistent. Interpretation. It was difficult to reach a consensus on all epidemiological findings across the 23 published European studies because of critical differences in methods employed across the reports. We highly recommend the development of research guidelines to standardize definitional, case finding, and data reporting parameters to help establish a more precise description and hence utility of the epidemiology of TBI in Europe.

Review Article A systematic review of brain injury epidemiology in Europe

Background. The world’s literature on traumatic brain injury (TBI) grows annually including new reports on epidemiologic findings from many regions. With the wide variety of reports emphasizing various factors it is useful to compile these findings, hence the objective of this report. Thus, we describe epidemiological factors from European studies largely published in the last 20 years.

A systematic review of brain injury epidemiology in Europe.

The WHO Collaborating Centre for Neurotrauma Task Force on Mild Traumatic Brain Injury performed a comprehensive search and critical review of the literature published between 1980 and 2002 to assemble the best evidence on the epidemiology, diagnosis, prognosis and treatment of mild traumatic brain injury. Of 743 relevant studies, 313 were accepted on scientific merit and comprise our best-evidence synthesis. The current literature on mild traumatic brain injury is of variable quality and we report the most common methodological flaws. We make recommendations for avoiding the shortcomings evident in much of the current literature and identify topic areas in urgent need of further research. This includes the need for large, well-designed studies to support evidence-based guidelines for emergency room triage of children with mild traumatic brain injury and to explore more fully the issue of prognosis after mild traumatic brain injury in the elderly population. We also advocate use of standard criteria for defining mild traumatic brain injury and propose a definition.

/pdf/methodological-issues-and-research-recommendations-for-mild-35snrhasdu.pdf

Methodological issues and research recommendations for mild traumatic brain injury: the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury.

To determine what consequences cognitive, behavioural or somatic impairments had on disabilities and recovery after a head injury (HI), a population-based sample of 231 adult patients was studied 5 years after an HI. Eighty lower-limb-injured (LLI) patients were considered as controls. Sixty-four LLI and 176 HI patients were reviewed (114 minor, 35 moderate, and 27 severe HI). Prevalence values of headaches (44-54%), dizziness (26-37%), and anxiety (47-63%) were not significantly different in the three HI severity groups, but were significantly lower in patients with an isolated limb injury (12-15%). Memory problems and depressive mood increased with injury severity. Mental impairments were frequent in severe HI patients (18-40% of patients). In minor and moderate HI patients, most disabilities were related to associated injuries. According to the Glasgow Outcome Scale (GOS), recovery was not considered as good because of somatic, behavioural or cognitive complaints in 2.5%, 5.7% and 59.2% of surviving patients in each of the above HI groups. Somatic or behavioural complaints may have considerable consequences in some minor HI patients, and the long-term management of certain patients needs improvement because these impairments are misunderstood.

Prevalence of impairments 5 years after a head injury, and their relationship with disabilities and outcome

Road accident statistics: discrepancies between police and hospital data in a French island.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/0014-5793%2887%2980554-9

Uncoupling effects of local anesthetics on rat liver mitochondria

Objective : Most studies on patients with severe brain injury (SBI) are based on data from specialized centres. This prospective epidemiologic study included all patients in a defined region with a coma lasting more than 24 hours or leading to a death. Methods : All patients with a SBI admitted to an emergency department in the region were included during a 1-year period. A data form was completed with initial neurological state, CT scan lesions and associated injuries. Outcome at the end of acute hospitalization was assessed from medical notes. Results : Two hundred and forty-eight patients were registered. Annual incidence was 8.5/100 000 population. Median age was 41 years. Traffic crashes were the most frequent cause (59%). Falls occurred in 30% (16% from a high level, 14% from one level). Initial GCS was above 8 in 31%, and patients with a neurological deterioration were older (52 vs 32 years). Death occurred in 52% of the cohort. Outcome was related to CT scan diagnosis, delay before eye opening and...

Epidemiology of traumatic comas: a prospective population-based study

To determine whether hyperglycemia in brain-dead donors is a sign of endocrine pancreas insufficiency, we studied pancreatic function in 25 consecutive brain dead patients. Blood samples were drawn at 2-hr intervals from donor referral until organ procurement to analyze glucose, insulin, and C-peptide levels. After donor retrieval, two specimens were taken from the pancreas for a subsequent immunohistochemical examination. At referral mean glycemia was 13.60 +/- 1.49 mmol/L, and there was a large range of plasma glucose levels (4.6-31.6). Of 25 patients, 16 had glycemia above 10 mmol/L. At organ procurement a mean of 20 hr later, mean glycemia as 8.61 +/- 0.58 mmol/L (P < 0.005 with paired t test), and only 5 patients had glycemia above 10 mmol/L. Hyperglycemia was associated with elevated insulin and C-peptide levels during donor management. An elevated C-peptide/glucose molar ratio might be considered a sign of peripheral insulin resistance. Hyperglycemia above 25 mmol/L could not be related to the amount of glucose administered during donor maintenance. Severe hyperglycemia had a natural tendency to be partly corrected. Histologic and immunohistochemical examinations were available in 17 cases and can be considered normal. It is concluded that endocrine pancreatic function can be considered effective after brain death. The mechanism of the relative insulin resistance of these patients requires further study. Blood glucose levels, in the range observed in this study, are not a good donor criterion of endocrine pancreatic function before pancreas transplantation.

P. Erny

Papers

Prevalence of impairments 5 years after a head injury, and their relationship with disabilities and outcome

Road accident statistics: discrepancies between police and hospital data in a French island.

Uncoupling effects of local anesthetics on rat liver mitochondria

Epidemiology of traumatic comas: a prospective population-based study

The endocrine pancreas in brain-dead donors. A prospective study in 25 patients.