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.

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.

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 (ß = .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.

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 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.