Thalamo-Prefrontal Connectivity Correlates with Early Command-Following After Severe Traumatic Brain injury

Recovery of consciousness after traumatic brain injury (TBI) is heterogeneous and difficult to predict. Structures such as the thalamus and prefrontal cortex are thought to be important in facilitating consciousness. We sought to investigate whether the integrity of thalamo-prefrontal circuits, assessed via diffusion tensor imaging (DTI), was associated with the return of goal-directed behavior after severe TBI. We classified a cohort of severe TBI patients (N = 25, 20 males) into Early and Late/Never outcome groups based on their ability to follow commands within 30 days post-injury. We assessed connectivity between whole thalamus, and mediodorsal thalamus (MD), to prefrontal cortex (PFC) subregions including dorsolateral PFC (dlPFC), medial PFC (mPFC), anterior cingulate (ACC), and orbitofrontal (OFC) cortices. We found that the integrity of thalamic projections to PFC subregions (L OFC, L and R ACC, and R mPFC) was significantly associated with Early command-following. This association persisted when the analysis was restricted to prefrontal-mediodorsal (MD) thalamus connectivity. In contrast, dlPFC connectivity to thalamus was not significantly associated with command-following. Using the integrity of thalamo-prefrontal connections, we created a linear regression model that demonstrated 72% accuracy in predicting command-following after a leave-one-out analysis. Together, these data support a role for thalamo-prefrontal connectivity in the return of goal-directed behavior following TBI.

Clinical Significance of Vascular Occlusive Events following Moderate-to-Severe Traumatic Brain Injury: An Observational Cohort Study

Preventing hemorrhage progression is a potential therapeutic opportunity in traumatic brain injury (TBI) management, but its use has been limited by fear of provoking vascular occlusive events (VOEs). However, it is currently unclear whether VOE actually affects outcome in these patients. The aim of this study was to determine incidence, risk factors, and clinical significance of VOE in patients with moderate-to-severe TBI. A retrospective observational cohort study of adults (≥15 years) with moderate-to-severe TBI was performed. The presence of a VOE during hospitalization was noted from hospital charts and radiological reports. Functional outcome, using the Glasgow Outcome Scale (GOS), was assessed at 12 months posttrauma. Univariate and multivariate logistic regressions were used for endpoint assessment. In total, 848 patients were included, with a median admission Glasgow Coma Scale of 7. A VOE was detected in 54 (6.4%) patients, of which cerebral venous thrombosis was the most common (3.2%), followed by pulmonary embolism (1.7%) and deep vein thrombosis (1.3%). Length of ICU stay (p < 0.001), body weight (p = 0.002), and skull fracture (p = 0.004) were independent predictors of VOE. VOE development did not significantly impact 12-month GOS, even after adjusting for potential confounders using propensity score matching. In conclusion, VOE in moderate-to-severe TBI patients was relatively uncommon, and did not affect 12-month GOS. This suggests that the potential benefit of treating bleeding progression might outweigh the risks of VOE.

Evacuation Strategies for U.S. Casualties with Traumatic Brain Injury (TBI) with and without Polytrauma

ABSTRACT Introduction According to the Military Health System Traumatic Brain Injury (TBI) Center of Excellence, 51,261 service members suffered moderate to severe TBI in the last 21 years. Moderate to severe TBI in service members is usually related to blast injury in combat operations, which necessitates medical evacuation to higher levels of care. Prevention of secondary insult, and mitigation of the unique challenges associated with the transport of TBI patients in a combat setting are important in reducing the morbidity and mortality associated with this injury. The primary goal of this study was a secondary analysis comparing the impact of time to transport on clinical outcomes for TBI patients without polytrauma versus TBI patients with polytrauma transported out of the combat theater via Critical Care Air Transport Teams (CCATT). Our secondary objective was to describe the occurrence of in-flight events and interventions for TBI patients without polytrauma versus TBI with polytrauma to assist with mission planning for future transports. Materials and Methods We performed a secondary analysis of a retrospective cohort of 438 patients with TBI who were evacuated out of theater by CCATT from January 2007 to May 2014. Polytrauma was defined as abbreviated injury scale (AIS) of at least three to another region in addition to head/neck. Time to transport was defined as the time (in days) from injury to CCATT evacuation out of combat theater. We calculated descriptive statistics and examined the associations between time to transport and preflight characteristics, in-flight interventions and events, and clinical outcomes for TBI patients with and without polytrauma. Results We categorized patients into two groups, those who had a TBI without polytrauma (n = 179) and those with polytrauma (n = 259). Within each group, we further divided those that were transported within 1 day of injury, in 2 days, and 3 or more days. Patients with TBI without polytrauma transported in 1 or 2 days were more likely to have a penetrating injury, an open head injury, a preflight Glascow Coma Score (GCS) of 8 or lower, and be mechanically ventilated compared to those transported later. Patients without polytrauma who were evacuated in 1 or 2 days required more in-flight interventions compared to patients without polytrauma evacuated later. Patients with polytrauma who were transported in 2 days were more likely to receive blood products, and patients with polytrauma who were evacuated within 1 day were more likely to have had at least one episode of hypotension en route. Polytrauma patients who were evacuated in 2–3 days had higher hospital days compared to polytrauma with earlier evacuations. There was no significant difference in mortality between any of the groups. Conclusions In patients with moderate to severe TBI transported via CCATT, early evacuation was associated with a higher rate of in-flight hypotension in polytrauma patients. Furthermore, those who had TBI without polytrauma that were evacuated in 1–2 days received more in-flight supplementary oxygen, blood products, sedatives, and paralytics. Given the importance of minimizing secondary insults in patients with TBI, recognizing this in this subset of the population may help systematize ways to minimize such events. Traumatic Brain Injury patients with polytrauma may benefit from further treatment and stabilization in theater prior to CCATT evacuation.

Delayed Diplopia After Sports-Related Concussion: A Multidisciplinary Approach to Evaluation and Management

ObjectiveTo highlight a multidisciplinary approach to the diagnosis and management of unilateral abducens palsy after a sports-related concussion.BackgroundMild traumatic brain injury (TBI) often leads to disruptions in visual functioning, affecting convergence, saccades, smooth pursuit, and accommodation. More severe TBI injuries may result in structural injuries to the ocular muscles, nerves, or the brain itself.Design/MethodsNA.ResultsCase: We present the case of a 33-year-old male with unilateral abducens nerve palsy after a sports-related concussion with loss of consciousness and multiple hemorrhagic contusions. The patient's visual symptoms manifested several days after the injury. With a multi-disciplinary evaluation involving specialists representing neurosurgery, endovascular neurology and neuro-ophthamology, unenhanced magnetic resonance imaging revealed multiple foci of intraparenchymal microhemorrhages and siderosis consistent with diffuse axonal injury (DAI), and an incidental parasagittal cavernoma. The delayed development of a sixth nerve palsy raised our suspicion for secondary axotomy, as has been described following TBI. While the probability of recovery is high, close follow up is imperative to address evolution of the patient's symptoms. In this case, the patient developed imbalance and headaches in association with his visual symptoms. For the imbalance we use physical therapy with therapists trained in vestibular therapy and for the visual symptoms we use vision therapy with trained optometrists.ConclusionsDelayed post-traumatic abducens palsy is concerning for DAI and secondary axotomy. Multidisciplinary assessment imparts the ability to evaluate for all possible causes and provide additional specialized care for recovery.

Sedation-Induced Burst Suppression Predicts Positive Outcome Following Traumatic Brain Injury

While electroencephalogram (EEG) burst-suppression is often induced therapeutically using sedatives in the intensive care unit (ICU), there is hitherto no evidence with respect to its association to outcome in moderate-to-severe neurological patients. We examined the relationship between sedation-induced burst-suppression (SIBS) and outcome at hospital discharge and at 6-month follow up in patients surviving moderate-to-severe traumatic brain injury (TBI). For each of 32 patients recovering from coma after moderate-to-severe TBI, we measured the EEG burst suppression ratio (BSR) during periods of low responsiveness as assessed with the Glasgow Coma Scale (GCS). The maximum BSR was then used to predict the Glasgow Outcome Scale extended (GOSe) at discharge and at 6 months post-injury. A multi-model inference approach was used to assess the combination of predictors that best fit the outcome data. We found that BSR was positively associated with outcomes at 6 months (P = 0.022) but did not predict outcomes at discharge. A mediation analysis found no evidence that BSR mediates the effects of barbiturates or propofol on outcomes. Our results provide initial observational evidence that burst suppression may be neuroprotective in acute patients with TBI etiologies. SIBS may thus be useful in the ICU as a prognostic biomarker.

Finding Goal Focus With People With Severe Traumatic Brain Injury in a Person-Centered Multi-Component Community Connection Program (M-ComConnect)

Background and Objectives: Loss of social connections in the community is a common consequence of severe traumatic brain injury (TBI), resulting in reduced well-being and quality of life. M-ComConnect is an individualized multi-component community connection intervention with the key objectives of increasing social activity, developing social relationships, and supporting community participation following severe TBI. As part of the M-ComConnect approach, semi-structured initial interviews were conducted to develop a holistic understanding of each participant and their goal focus for the project. In this paper we describe how clinicians worked with participants to identify a desired community-based social activity in which to participate.Method: Transcripts of initial interviews between participant and clinician were analyzed using the phases of reflexive thematic analysis developed by Braun and Clarke. Participants were ten individuals aged between 24 and 75 with severe TBI. All were living in the community and reported reduced social connections since their TBI. The aim of the analysis was to evaluate the skills and strategies used by clinicians in their interactions with participants to derive goal focus for the program.Results: Thematic analysis of initial interview data revealed three main categories and fourteen sub-categories of clinical strategies. These were: (1) Humanizing (curiosity; demonstrating respect and empathy; providing compliments and affirmations; simple reflections; revealing aspects of self; and humor and laughter), (2) Empowering (emphasizing choice and control; highlighting strengths; identifying roadblocks and reframing to reveal opportunities; and collaborative problem solving), and (3) Focusing (making suggestions; identifying preferences; working with ideas; and negotiating). These strategies aligned with the program's relational approach and supported the core processes of the goal-focussing framework, namely understanding and connecting with you, building a relationship, and working together with you to find focus.Conclusion: The goal-focusing framework and clinical strategies outlined provide guidance for clinicians working with people with TBI in the community and is a promising way to engage clients when focusing on individualized social activity-based goals.