Mild traumatic brain injury

Serial measurement of memory and diffusion tensor imaging changes within the first week following uncomplicated mild traumatic brain injury

Authors: Wilde EA, McCauley SR, Barnes A, Wu TC, Chu Z, Hunter JV, Bigler ED.

Patients (n = 8) with uncomplicated mild traumatic brain injury (mTBI) underwent serial assessments (4) with diffusion tensor imaging (DTI) and neuropsychological testing within the first 8 days post-injury. Using a multi-case study design, we examined changes in brain parenchyma (via DTI-derived fractional anisotropy , apparent diffusion coefficient , axial diffusivity and radial diffusivity in the left cingulum bundle) and in memory performance (via Hopkins Verbal Learning Test-Revised). Qualitative inspection of the results indicated that memory performance was transiently affected in most participants over the course of the week, with performance most negatively impacted on the second assessment (days 3-4 or 97-144 h post-injury), and then returning to within normal limits by 8 days post-injury. Alternatively, FA and other DTI metrics showed a more complex pattern, with the trajectory of some participants changing more prominently than others. For example, FA transiently increased in some participants over the study period, but the pattern was heterogeneous. Memory performance appeared to mirror changes in FA in certain cases, supporting a pathophysiological basis to memory impairment following mTBI. However, the pattern and the degree of symmetry between FA and memory performance was complex and did not always correspond. Serial imaging over the semi-acute recovery period may be important in reconciling conflicting findings in mTBI utilizing memory and/or DTI. Serial use of imaging modalities including DTI may aid understanding of underlying pathophysiological changes in the semi-acute post-injury period. Should a consistent pattern emerge that allows identification of patients at-risk for acute and/or persistent symptoms, such knowledge could guide development of therapeutic targets in mTBI and in understanding the most effective administration time window for these agents.

Concussion in athletics: ongoing clinical and brain imaging research controversies

Authors: Slobounov S, Gay M, Johnson B, Zhang K.

Concussion, the most common form of traumatic brain injury, proves to be increasingly complex and not mild in nature as its synonymous term mild traumatic brain injury (mTBI) would imply. Despite the increasing occurrence and prevalence of mTBI there is no universally accepted definition and conventional brain imaging techniques lack the sensitivity to detect subtle changes it causes. Moreover, clinical management of sports induced mild traumatic brain injury has not changed much over the past decade. Advances in neuroimaging that include electroencephalography (EEG), functional magnetic resonance imaging (fMRI), resting-state functional connectivity, diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) offer promise in aiding research into understanding the complexities and nuances of mTBI which may ultimately influence clinical management of the condition. In this paper the authors review the major findings from these advanced neuroimaging methods along with current controversy within this field of research. As mTBI is frequently associated with youth and sports injury this review focuses on sports-related mTBI in the younger population.

Mild traumatic brain injury diagnosis frequently remains unrecorded in subjects with craniofacial fractures

Authors: Puljula J, Cygnel H, Mäkinen E, Tuomivaara V, Karttunen V, Karttunen A, Hillbom M.

BACKGROUND: Traumatic brain injuries (TBI) in subjects with craniofacial fractures are usually diagnosed by emergency room physicians. We investigated how often TBI remains unrecorded in these subjects, and whether diagnostic accuracy has improved after the implementation of new TBI guidelines.
METHODS: All subjects with craniofacial fractures admitted to Oulu University Hospital in 1999 and in 2007 were retrospectively identified. New guidelines for improving the diagnostic accuracy of TBI were implemented between 2000 and 2006. Clinical symptoms of TBI were gathered from notes on hospital charts and compared to the recorded diagnoses at discharge. Logistic regression was used to identify independent predictors for TBI to remain unrecorded.
RESULTS: Of 194 subjects with craniofacial fracture, 111(57%) had TBI, 40 in 1999 and 71 in 2007. Fifty-one TBIs (46%) remained unrecorded at discharge, 48 being mild and 3 moderate-to-severe. Subjects with unrecorded TBI were significantly less frequently referred to follow-up visits. Failures to record the TBI diagnosis were less frequent (29/71, 41%) in 2007 than in 1999 (22/40, 55%), but the difference was not statistically significant. The most significant independent predictor for this failure was the clinical specialty (other than neurology/neurosurgery) of the examining physician (p<0.001). The subject's alcohol intoxication did not hamper the diagnosis of TBI.
CONCLUSIONS: TBIs remain frequently unrecorded in subjects with craniofacial fractures. Recording of mild TBI slightly but insignificantly improved after the implementation of new guidelines.

Mild traumatic brain injury: lessons learned from clinical, sports, and combat concussions

Authors: Kelly JC, Amerson EH, Barth JT.

Over the past forty years, a tremendous amount of information has been gained on the mechanisms and consequences of mild traumatic brain injuries. Using sports as a laboratory to study this phenomenon, a natural recovery curve emerged, along with standards for managing concussions and returning athletes back to play. Although advances have been made in this area, investigation into recovery and return to play continues. With the increase in combat-related traumatic brain injuries in the military setting, lessons learned from sports concussion research are being applied by the Department of Defense to the assessment of blast concussions and return to duty decision making. Concussion management and treatment for military personnel can be complicated by additional combat related stressors not present in the civilian environment. Cognitive behavioral therapy is one of the interventions that has been successful in treating symptoms of postconcussion syndrome. While we are beginning to have an understanding of the impact of multiple concussions and subconcussive blows in the sports world, much is still unknown about the impact of multiple blast injuries.

GFAP and S100B in the acute phase of mild traumatic brain injury

Authors: Metting Z, Wilczak N, Rodiger LA, Schaaf JM, van der Naalt J.

OBJECTIVE: The biomarkers glial fibrillary acid protein (GFAP) and S100B are increasingly used as prognostic tools in severe traumatic brain injury (TBI). Data for mild TBI are scarce. This study aims to analyze the predictive value of GFAP and S100B for outcome in mild TBI and the relation with imaging.
METHODS: In 94 patients biomarkers were determined directly after admission. Collected data included injury severity, patient characteristics, admission CT, and MRI 3 months postinjury. Six months postinjury outcome was determined with Glasgow Outcome Scale Extended (GOSE) and return to work (RTW).
RESULTS: Mean GFAP was 0.25 μg/L (SD 1.08) and S100B 0.54 μg/L (SD 1.18). In 63% GFAP was not discernible. GFAP was increased in patients with an abnormal CT (1.20 μg/L, SD 2.65) compared to normal CT (0.05 μg/L, SD 0.17, p < 0.05). Also in patients with axonal injury on MRI GFAP was higher (0.65 μg/L, SD 0.91 vs 0.07 μg/L, SD 0.2, p < 0.05). GFAP was increased in patients with incomplete RTW compared to complete RTW (0.69 μg/L, SD 2.11 vs 0.12 μg/L, SD 0.38, p < 0.05). S100B was not related to outcome or imaging studies. In multivariate analysis GFAP was not predictive for outcome determined by GOSE and RTW.
CONCLUSIONS: A relation between GFAP with imaging studies and outcome (determined by RTW) was found in contrast to S100B. As the positive predictive value of GFAP is limited in this category of TBI patients, this biomarker is not suitable for prediction of individual patient outcome.

Posttraumatic headache

Authors: Vargas BB, Dodick DW.

PURPOSE OF REVIEW: Posttraumatic headache (PTH) is a commonly occurring and potentially disabling consequence of concussion and mild traumatic brain injury (mTBI). This brief review highlights recent advances in the epidemiology, evaluation, and management of concussion, mTBI, and PTH.
RECENT FINDINGS: Current epidemiological studies suggest that previous estimates of concussion and mTBI incidence are grossly underestimated and have also helped to identify specific activities and demographic groups that might be more susceptible. Concussion results in profound metabolic derangements during which the brain is potentially vulnerable to repeat injury and permanent damage. Imaging studies such as magnetic resonance (MR) spectroscopy and diffusion tensor imaging have proven to be effective at identifying these abnormalities both acutely and also weeks after symptoms resolution. To date, there have been no randomized, placebo-controlled studies supporting the efficacy of any treatment for PTH and current therapeutic decisions are guided only by expert opinion and current evidence-based guidelines for the treatment of specific primary headache phenotypes, the most commonly occurring of which is migraine.
SUMMARY: Despite numerous advances in the awareness, pathophysiology, and diagnostic workup of concussion, mTBI, and PTH, there is a paucity of evidence-based guidance regarding treatment.


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