Mild traumatic brain injury

Imaging modalities in mild traumatic brain injury and sports concussion

Authors: Gonzalez PG, Walker MT.

Mild traumatic brain injury is a significant public health issue that has been gaining considerable attention over the past few years. After injury, a large percentage of patients experience postconcussive symptoms that affect work and school performance and that carry significant medicolegal implications. Conventional imaging modalities (computed tomography and magnetic resonance imaging) are insensitive to microstructural changes and underestimate the degree of diffuse axonal injury and metabolic changes. Newer imaging techniques have attempted to better diagnose and characterize diffuse axonal injury and the metabolic and functional aspects of traumatic brain injury. The following review article summarizes the currently available imaging studies and describes the novel and more investigational techniques available for mild traumatic brain injury. A suggested algorithm is offered.

Long-term consequences: effects on normal development profile after concussion

Authors: Daneshvar DH, Riley DO, Nowinski CJ, McKee AC, Stern RA, Cantu RC.

Each year in the United States, approximately 1.7 million people are diagnosed with a traumatic brain injury (TBI), about 75% of which are classified as mild TBIs or concussions. Although symptoms typically resolve in a matter of weeks, both children and adults may suffer from postconcussion syndrome for months or longer. A progressive tauopathy, chronic traumatic encephalopathy, is believed to stem from repeated brain trauma. Alzheimer-like dementia, Parkinsonism, and motor neuron disease are also associated with repetitive brain trauma. Effective diagnoses, treatments, and education plans are required to reduce the future burden and incidence of long-term effects of head injuries.

Sports-related chronic repetitive head trauma as a cause of pituitary dysfunction

Authors: Dubourg J, Messerer M.

Traumatic brain injury (TBI) is recognized as a cause of hypopituitarism even after mild TBI. Although over the past decade, a growing body of research has detailed neuroendocrine changes induced by TBI, the mechanisms and risk factors responsible for this pituitary dysfunction are still unclear. Around the world, sports-especially combative sports-are very popular. However, sports are not generally considered as a cause of TBI in most epidemiological studies, and the link between sports-related head trauma and hypopituitarism has not been investigated until recently. Thus, there is a paucity of data regarding this important concern. Because of the large number of young sports participants with near-normal life expectancy, the implications of undiagnosed or untreated postconcussion pituitary dysfunction can be dramatic. Understanding the pathophysiological mechanisms and risk factors of hypopituitarism caused by sports injuries is thus an important issue that concerns both medical staff and sponsors of sports. The aim of this paper was to summarize the best evidence for understanding the pathophysiological mechanisms and to discuss the current data and recommendations on sports-related head trauma as a cause of hypopituitarism.

Diffuse and spatially variable white matter disruptions are associated with blast-related mild traumatic brain injury

Authors: Davenport ND, Lim KO, Armstrong MT, Sponheim SR.

Mild traumatic brain injury (mTBI) due to explosive blast is common among military service members and often associated with long term psychological and cognitive disruptions. Little is known about the neurological effects of blast-related mTBI and whether they differ from those of civilian, non-blast mTBI. Given that brain damage from blasts may be diffuse and heterogeneous, we tested the hypothesis that blast mTBI is associated with subtle white matter disruptions in the brain that are spatially inconsistent across individuals. We used diffusion tensor imaging to examine white matter integrity, as quantified by fractional anisotropy (FA), in a group of American military service members with (n=25) or without (n=33) blast-related mTBI who had been deployed as part of Operation Iraqi Freedom or Operation Enduring Freedom. History of civilian non-blast mTBI was equally common across groups, which enabled testing of both blast and non-blast mTBI effects on measures sensitive to (1) concentrated, spatially consistent (average FA within a region of interest ), (2) concentrated, spatially variable (number of ROIs with low average FA), and (3) diffuse (number of voxels with low FA) disruptions of white matter integrity. Blast mTBI was associated with a diffuse, global pattern of lower white matter integrity, and this pattern was not affected by previous civilian mTBI. Neither type of mTBI had an effect on the measures sensitive to more concentrated and spatially consistent white matter disruptions. Additionally, individuals with more than one blast mTBI tended to have a larger number of low FA voxels than individuals with a single blast injury. These results indicate that blast mTBI is associated with disrupted integrity of several white matter tracts, and that these disruptions are diluted by averaging across the large number of voxels within an ROI. The reported pattern of effects supports the conclusion that the neurological effects of blast mTBI are diffuse, widespread, and spatially variable.

When a minor head injury results in enduring symptoms: a prospective investigation of risk factors for postconcussional syndrome after mild traumatic brain injury

Authors: Hou R, Moss-Morris R, Peveler R, Mogg K, Bradley BP, Belli A.

ObjectiveA significant proportion (15-30%) of patients with mild traumatic brain injury (MTBI) are at risk of developing postconcussional syndrome (PCS). The aim of this study was to investigate the contributions of cognitive, emotional, behavioural and social factors to the development of PCS and identify early predictors.MethodsA prospective cohort design was employed. 126 MTBI patients completed baseline questionnaire assessments within 2 weeks of the injury and 107 completed follow-up questionnaire assessments at 3 and 6 months. A series of self-report measures were used to assess cognitive, behavioural and emotional responses to MTBI. The primary outcome was the ICD-10 diagnosis for PCS. Demographic and clinical characteristic variables were compared between PCS cases and non-cases using independent sample t tests and χ(2) tests. Individual and multivariate logistic regression analyses were used to detect predictors of PCS.ResultsOf 107 MTBI patients, 24 (22%) met the criteria for PCS at 3 months and 22 (21%) at 6 months. Individual logistic regression analysis indicated that negative MTBI perceptions, stress, anxiety, depression and all-or-nothing behaviour were associated with the risk of PCS. Multivariate analysis revealed that all-or-nothing behaviour was the key predictor for the onset of PCS at 3 months while negative MTBI perceptions predicted PCS at 6 months.ConclusionsThe study provides good support for the proposed cognitive behavioural model. Patients' perceptions of their head injury and their behavioural responses play important roles in the development of PCS, indicating that cognitive and behavioural factors may be potential targets for early preventive interventions.

Disability 3, 12, and 24 Months After Traumatic Brain Injury Among Children and Adolescents

Authors: Rivara FP, Koepsell TD, Wang J, Temkin N, Dorsch A, Vavilala MS, Durbin D, Jaffe KM.

Objective:To examine disability in children and adolescents after traumatic brain injury (TBI) across the spectrum of injury severity.Methods:This was a prospective cohort study of children younger than 18 years treated for a TBI (n = 729) or an arm injury (n = 197) between March 1, 2007, and September 30, 2008. The main outcome measures were disability in health-related quality of life, adaptive skills, and participation in social and community activities 3, 12, and 24 months after injury compared with preinjury functioning.Results:The health-related quality of life for children with moderate or severe TBI was lower at all follow-up times compared with baseline, but there was some improvement during the first 2 years after injury. Three months after injury, there was a substantial decrease in the level of activities in which children with moderate and severe TBI were able to participate; these activities improved at 12 and 24 months but were still significantly impaired. Communication and self-care abilities in children with moderate and severe TBI were lower at 3 months than at baseline and did not improve by 24 months. Children who met the definition of mild TBI but had an intracranial hemorrhage had lower quality-of-life scores at 3 months.Conclusions:Children with moderate or severe TBI and children with mild TBI who had intracranial hemorrhage had substantial long-term reduction in their quality of life, participation in activities with others, and ability to communicate and care for themselves.

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