Use of a multi-level mixed methods approach to study the effectiveness of a primary care progressive return to activity protocol after acute mild traumatic brain injury/concussion in the military

Designing research on concussion treatment in the military setting: Important challenges to consider

Traumatic brain injury (TBI) is highly prevalent on a global scale with concussion being the most common of all TBIs. Concussion research on rehabilitation and symptom resolution is well-established, particularly among athletes, but less is known about the recovery of active duty service members (ADSMs). In a population whose occupational environment increases risk for such injury, it is imperative that treatment is optimized to achieve successful rehabilitation. The military setting, however, has challenges that must be accounted for when developing proposals to study the benefits of new interventions or treatment. This review will provide a discussion on those challenges to better understand the considerations that are essential during the developmental phase of concussion studies within the military setting. This review aims to provide investigators novice to the military setting an overview of considerations when researching concussion among ADSMs.

Impact of Prior Brain Injury on Concussion Recovery in Military Personnel: Evaluation of Timing Between Concussions

OBJECTIVE

To evaluate the potential impact of timing between the current and the most recent previous concussions on symptom severity among acutely concussed active duty military Service members (SMs).

SETTING

Three military installations.

PARTICIPANTS

Eighty-four SMs aged 18 to 44 years who sustained a concussion within 72 hours of enrollment. No previous concussion within 1 year preenrollment.

DESIGN

Longitudinal study with enrollment within 72 hours of injury, and follow-up at 1 week and 1 month postinjury.

MAIN MEASURES

Lifetime concussion history (yes/no) and recency of the latest concussion (no history, relatively more recent [1 to <6 years ago], and more remote [6+ years ago]) from the current concussion using the Ohio State University Traumatic Brain Injury Identification Method-Interview Form. Symptom severity (total and by categories: cognitive, affective, somatosensory, vestibular) at all time points using the Neurobehavioral Symptoms Inventory.

RESULTS

Concussion history assessed as having any previous concussion was not found significantly related to symptom severity (total or by categories) following a current concussion. However, when timing between concussion was taken into account, time since previous concussion was significantly related to symptomatology, whereby those with relatively more recent previous concussion had greater total symptoms within 72 hours of injury and at 1 week postinjury (though not at 1 month) than those with more remote previous concussion (≤72 hours: difference = 15.4, 95% CI = 1.8 to 29.1; 1 week: difference = 15.2, 95% CI = 1.2 to 29.2) or no history (≤72 hours: difference = 11.6, 95% CI = 0.4 to 22.8; 1 week: difference = 13.9, 95% CI = 2.4 to 25.4). When evaluated by symptom category, this relationship was particularly important on affective and somatosensory symptoms.

CONCLUSION

In recently concussed active duty SMs, the timing between the current and previous concussions may be an important factor in determining prognosis. Clinical assessment of concussion history that accounts for the timing of the most recent event may be necessary to identify patients who may require a more conservative plan of care and more gradual return to activity in the acute recovery stage.

A Review of Implementation Concepts and Strategies Surrounding Traumatic Brain Injury Clinical Care Guidelines

Despite considerable efforts to advance the science surrounding traumatic brain injury (TBI), formal efforts supporting the current and future implementation of scientific findings within clinical practice and healthcare policy are limited. While many and varied guidelines inform the clinical management of TBI across the spectrum, clinicians and healthcare systems are not broadly adopting, implementing, and/or adhering to them. As part of the Brain Trauma Blueprint TBI State of the Science, an expert workgroup was assembled to guide this review article, which describes: (1) possible etiologies of inadequate adoption and implementation; (2) enablers to successful implementation strategies; and (3) strategies to mitigate the barriers to adoption and implementation of future research.

Best Practices for Progressive Return to Activity after Concussion: Lessons Learned from a Prospective Study of U.S. Military Service Members

Primary care providers can play a crucial role in the clinical management of concussion. However, many providers lack up-to-date information about best practices for rest and return to activity after these injuries. Most research on this topic has been conducted in athletes, and so less is known about how to assist patients with returning to activity in other settings and populations. This article provides a review of best practices for management of progressive return to activity after concussion, with an emphasis on "lessons learned" from the Defense and Veterans Brain Injury Center (DVBIC) Progressive Return to Activity (PRA) study, a multi-site longitudinal research project conducted to evaluate concussion management practices and the effectiveness of provider training on DVBIC clinical recommendations (CRs). Provider clinical practices and patient outcomes were examined at three U.S. military treatment facilities before and after providers completed a standardized training on DVBIC PRA CRs. In summary, research findings provide additional support that concussion recovery can be influenced by patients' activity levels after injury. Patients with concussion may experience poorer outcomes if they return to pre-injury levels of activity too rapidly, but they may also be at risk for prolonged symptoms if they fail to increase activity levels over time after an initial period of rest. Additionally, training primary care providers in return to activity guidelines can result in more effective patient education and better clinical outcomes. This knowledge can be used to inform best practices for progressive return to activity in both civilian and military settings.

Beliefs About the Influence of Rest During Concussion Recovery May Predict Activity and Symptom Progression Within an Active Duty Military Population

OBJECTIVES

To evaluate relationships between beliefs about the impact of rest and the level of activities and symptoms over time among active duty Service members sustaining concussion, and whether these relationships vary by provision of concussion education.

DESIGN

Longitudinal study using multilevel modeling to assess the relationship between beliefs about rest within 72 hours of concussion and change in activity and symptom level over time, as well as interaction by concussion education at the initial clinic visit.

SETTING

Three military treatment facilities.

PARTICIPANTS

Study participants included active duty Service members diagnosed with a concussion (N=111; median age, 24 y). Individuals with previous history of concussion within 12 months of study enrollment were excluded.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Activity questionnaire and the Neurobehavioral Symptom Inventory assessed within 72 hours of concussion; at 1 week; and at 1, 3, and 6 month(s) postinjury.

RESULTS

Receipt of concussion education from providers was significantly associated with greater belief that rest influences concussion recovery. Greater belief that rest influences symptom recovery at the acute stage of concussion was associated with a greater increase in activities over time, but only among those who received education from their provider. Additionally, greater belief about the influence of rest was related to a more rapid decrease in symptoms over time.

CONCLUSIONS

Concussed Service members who underestimate the influence of rest during acute recovery may be at risk for poorer recovery. Treatment of Service members with postconcussive symptoms should consider patient knowledge and/or beliefs about rest and recovery, which may influence prognosis. Our results support the provider's use of concussion education to correct potential misconceptions that may negatively impact symptom recovery.

Use of the Progressive Return to Activity Guidelines May Expedite Symptom Resolution After Concussion for Active Duty Military

BACKGROUND

Clinical recommendations for concussion management encourage reduced cognitive and physical activities immediately after injury, with graded increases in activity as symptoms resolve. Empirical support for the effectiveness of such recommendations is needed.

PURPOSE

To examine whether training medical providers on the Defense and Veterans Brain Injury Center's Progressive Return to Activity Clinical Recommendation (PRA-CR) for acute concussion improves patient outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This study was conducted from 2016 to 2018 and compared patient outcomes before and after medical providers received an educational intervention (ie, provider training). Patients, recruited either before or after intervention, were assessed at ≤72 hours, 1 week, 1 month, 3 months, and 6 months after a concussion. The participant population included 38 military medical providers and 106 military servicemembers with a diagnosed concussion and treated by one of the military medical providers: 58 patient participants received care before the intervention (ie, provider training) and 48 received care after intervention. The primary outcome measure was the Neurobehavioral Symptom Inventory.

RESULTS

The patients seen before and after the intervention were predominantly male (89.7% and 93.8%, respectively) of military age (mean ± SD, 26.62 ± 6.29 years and 25.08 ± 6.85 years, respectively) and a mean ± SD of 1.92 ± 0.88 days from injury. Compared with patients receiving care before intervention, patients receiving care after intervention had smaller increases in physical activities (difference in mean change; 95% CI, 0.39 to 6.79) and vestibular/balance activities (95% CI, 0.79 to 7.5) during the first week of recovery. Although groups did not differ in symptoms at ≤72 hours of injury (d = 0.22; 95% CI, -2.21 to 8.07), the postintervention group reported fewer symptoms at 1 week (d = 0.61; 95% CI, 0.52 to 10.92). Postintervention patients who completed the 6-month study had improved recovery both at 1 month (d = 1.55; 95% CI, 5.33 to 15.39) and 3 months after injury (d = 1.10; 95% CI, 2.36 to 11.55), but not at 6 months (d = 0.35; 95% CI, 5.34 to 7.59).

CONCLUSION

Training medical providers on the PRA-CR for management of concussion resulted in expedited recovery of patients.

Activity Level During Acute Concussion May Predict Symptom Recovery Within an Active Duty Military Population

OBJECTIVE

To evaluate the impact on symptom resolution of activity acutely following a concussion and the role of acute-phase symptoms on this relationship among active duty service members (SMs).

SETTING

Three military installations.

PARTICIPANTS

Sixty-two SMs aged 18 to 44 years who sustained a concussion within 72 hours of enrollment.

DESIGN

Longitudinal design with data collected within 72 hours of injury (baseline, n = 62) and at 1 week (n = 57), 1 month (n = 50), 3 months (n = 41), and 6 months (n = 40) postinjury.

MAIN MEASURES

Baseline activity level using a 60-item Activity Questionnaire. Symptom level at baseline and during follow-up using Neurobehavioral Symptoms Inventory.

RESULTS

Significant interaction (Pi < .05) was found, with significant main effects (P < .05) limited to SMs with elevated baseline symptomatology. Among these participants, greater baseline total activity was significantly related to greater vestibular symptoms at 1, 3, and 6 months (β = .61, .63, and .59, respectively). Significant associations were also found for particular types of baseline activity (eg, physical; vestibular/balance; military-specific) and symptoms at 1, 3, and/or 6 months postinjury.

CONCLUSION

These results provide support for clinical guidance that symptomatic SMs, particularly those with high levels of acute symptoms, may need to avoid excessive activity acutely following concussion.

Activity Level and Type During Post-acute Stages of Concussion May Play an Important Role in Improving Symptoms Among an Active Duty Military Population

Background: Previous research demonstrates that early rest and gradual increases in activity after concussion can improve symptoms; however, little is known about the intensity and type of activity during post-acute time periods-specifically months post-injury-that may promote optimal recovery in an active duty service member (SM) population. Objective: The objectives of this study were to investigate how activity level and type at the post-acute stages of concussion (at 1 and 3 month[s] post-injury) impact subsequent symptoms among SMs, and how this relationship might differ by the level of symptoms at the time of injury. Methods: Participants included 39 SMs ages 19-44 years from 3 military installations who were enrolled within 72 h after sustaining a concussion. Linear regression was used to evaluate whether the association between activity level at 1 or 3 month(s) post-injury (as measured by a multi-domain Activity Questionnaire) and subsequent symptoms at 3 and/or 6 months (as measured by the Neurobehavioral Symptom Inventory) varied by the level of symptoms at acute stages of concussion. Partial correlation was used to evaluate relationships that did not differ by acute symptom level. Symptoms at the time of activity assessment (1 or 3 month[s]) were accounted for in all models, as well as activity level at acute stages of concussion. Results: Greater physical and vestibular/balance activity at 1 month were significantly correlated with lower symptoms at 3 months, but not at 6 months post-injury. There were no significant associations found between activity (total or by type) at 3 months and symptoms at 6 months. The association between activity level at either 1 or 3 months and subsequent symptoms at 3 and/or 6 months did not differ by the level of acute symptoms. Conclusion: The intensity and type of activities in which SMs engage at post-acute stages of concussion may impact symptom recovery. Although low levels of activity have been previously shown to be beneficial during the acute stage of injury, higher levels of activity may provide benefit at later stages. These findings provide support for the importance of monitoring and managing activity level beyond the acute stage of concussion.

Acute Post-Traumatic Sleep May Define Vulnerability to a Second Traumatic Brain Injury in Mice

Chronic neurological impairments can manifest from repetitive traumatic brain injury (rTBI), particularly when subsequent injuries occur before the initial injury completely heals. Herein, we apply post-traumatic sleep as a physiological biomarker of vulnerability, hypothesizing that a second TBI during post-traumatic sleep worsens neurological and histological outcomes compared to one TBI or a second TBI after post-traumatic sleep subsides. Mice received sham or diffuse TBI by midline fluid percussion injury; brain-injured mice received one TBI or rTBIs at 3- or 9-h intervals. Over 40 h post-injury, injured mice slept more than shams. Functional assessments indicated lower latencies on rotarod and increased Neurological Severity Scores for mice with rTBIs within 3 h. Anxiety-like behaviors in the open field task were increased for mice with rTBIs at 3 h. Based on pixel density of silver accumulation, neuropathology was greater at 28 days post-injury (DPI) in rTBI groups than sham and single TBI. Cortical microglia morphology was quantified and mice receiving rTBI were de-ramified at 14 DPI compared to shams and mice receiving a single TBI, suggesting robust microglial response in rTBI groups. Orexin-A-positive cells were sustained in the lateral hypothalamus with no loss detected, indicating that loss of wake-promoting neurons did not contribute to post-traumatic sleep. Thus, duration of post-traumatic sleep is a period of vulnerability that results in exacerbated injury from rTBI. Monitoring individual post-traumatic sleep is a potential clinical tool for personalized TBI management, where regular sleep patterns may inform rehabilitative strategies and return-to-activity guidelines.

Modeling the Long-Term Consequences of Repeated Blast-Induced Mild Traumatic Brain Injuries

Repeated mild traumatic brain injury (rmTBI) caused by playing collision sports or by exposure to blasts during military operations can lead to late onset, chronic diseases such as chronic traumatic encephalopathy (CTE), a progressive neurodegenerative condition that manifests in increasingly severe neuropsychiatric abnormalities years after the last injury. Currently, because of the heterogeneity of the clinical presentation, confirmation of a CTE diagnosis requires post-mortem examination of the brain. The hallmarks of CTE are abnormal accumulation of phosphorylated tau protein, TDP-43 immunoreactive neuronal cytoplasmic inclusions, and astroglial abnormalities, but the pathomechanism leading to these terminal findings remains unknown. Animal modeling can play an important role in the identification of CTE pathomechanisms, the development of early stage diagnostic and prognostic biomarkers, and pharmacological interventions. Modeling the long-term consequences of blast rmTBI in animals is especially challenging because of the complexities of blast physics and animal-to-human scaling issues. This review summarizes current knowledge about the pathobiologies of CTE and rmbTBI and discusses problems as well as potential solutions related to high-fidelity modeling of rmbTBI and determining its long-term consequences.