Loss of Consciousness and Altered Mental State as Predictors of Functional Recovery Within 6 Months Following Mild Traumatic Brain Injury

Mechanisms of Injury Leading to Concussions in Collegiate Soccer Players: A CARE Consortium Study

BACKGROUND

Few previous studies have investigated how different injury mechanisms leading to sport-related concussion (SRC) in soccer may affect outcomes.

PURPOSE

To describe injury mechanisms and evaluate injury mechanisms as predictors of symptom severity, return to play (RTP) initiation, and unrestricted RTP (URTP) in a cohort of collegiate soccer players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The Concussion Assessment, Research and Education (CARE) Consortium database was used. The mechanism of injury was categorized into head-to-ball, head-to-head, head-to-body, and head-to-ground/equipment. Baseline/acute injury characteristics-including Sports Concussion Assessment Tool-3 total symptom severity (TSS), loss of consciousness (LOC), and altered mental status (AMS); descriptive data; and recovery (RTP and URTP)-were compared. Multivariable regression and Weibull models were used to assess the predictive value of the mechanism of injury on TSS and RTP/URTP, respectively.

RESULTS

Among 391 soccer SRCs, 32.7% were attributed to a head-to-ball mechanism, 27.9% to a head-to-body mechanism, 21.7% to a head-to-head mechanism, and 17.6% to a head-to-ground/equipment mechanism. Event type was significantly associated with injury mechanism [χ2(3) = 63; P < .001), such that more head-to-ball concussions occurred in practice sessions (n = 92 [51.1%] vs n = 36 [17.1%]) and more head-to-head (n = 65 [30.8%] vs n = 20 [11.1]) and head-to-body (n = 76 [36%] vs n = 33 [18.3%]) concussions occurred in competition. The primary position was significantly associated with injury mechanism [χ2(3) = 24; P < .004], with goalkeepers having no SRCs from the head-to-head mechanism (n = 0 [0%]) and forward players having the least head-to-body mechanism (n = 15 [19.2%]). LOC was also associated with injury mechanism (P = .034), with LOC being most prevalent in head-to-ground/equipment. Finally, AMS was most prevalent in head-to-ball (n = 54 [34.2%]) and head-to-body (n = 48 [30.4%]) mechanisms [χ2(3) = 9; P = .029]. In our multivariable models, the mechanism was not a predictor of TSS or RTP; however, it was associated with URTP (P = .044), with head-to-equipment/ground injuries resulting in the shortest mean number of days (14 ± 9.1 days) to URTP and the head-to-ball mechanism the longest (18.6 ± 21.6 days).

CONCLUSION

The mechanism of injury differed by event type and primary position, and LOC and AMS were different across mechanisms. Even though the mechanism of injury was not a significant predictor of acute symptom burden or time until RTP initiation, those with head-to-equipment/ground injuries spent the shortest time until URTP, and those with head-to-ball injuries had the longest time until URTP.

Disentangling effects of remote mild traumatic brain injury characteristics and posttraumatic stress on processing speed and executive function in veterans

Mild traumatic brain injury (mTBI) and posttraumatic stress are prevalent in military service members and share objective and subjective cognitive symptoms, complicating recovery. We investigated the effects of remote mTBI characteristics and current posttraumatic stress symptoms on neuropsychological performance in 152 veterans with a history of remote mTBI and current cognitive concerns. Participants completed clinical neuropsychological evaluations within a Veterans Affairs Level-II TBI/Polytrauma outpatient clinic (i.e. tertiary trauma care center for US military veterans outside of a research or teaching hospital setting). Archival data analysis of mTBI injury characteristics, clinical diagnoses, scores on the Posttraumatic Stress Disorder Checklist-Military Version (PCL-M) and performance on tests of processing speed, attention and executive function was conducted. Hierarchical linear regression demonstrated that elevated PCL-M scores were associated with slower performance on trail making test (TMT) Parts A and B (p < .016). PCL-M symptoms moderated the effect of alteration of consciousness (AOC) on TMT performance, with endorsement of AOC associated with better performance, but only when PCL-M scores were high (p < .005). Follow-up mediation analyses demonstrated that PCL-M score fully mediated the relationship between AOC and TMT-A performance and partially mediated the relationship between AOC and TMT-B performance. Post-hoc analyses meant to separate the impact of processing speed on TMT-B were all non-significant. Remote mTBI characteristics, specifically AOC, were not associated with decrements in cognitive performance. Posttraumatic symptoms were associated with worse processing speed, suggesting that psychological distress and psychopathology are contributing factors in understanding and treating persistent cognitive distress following remote mTBI.

Loss of Consciousness and Righting Reflex Following Traumatic Brain Injury: Predictors of Post-Injury Symptom Development (A Narrative Review)

Identifying predictors for individuals vulnerable to the adverse effects of traumatic brain injury (TBI) remains an ongoing research pursuit. This is especially important for patients with mild TBI (mTBI), whose condition is often overlooked. TBI severity in humans is determined by several criteria, including the duration of loss of consciousness (LOC): LOC < 30 min for mTBI and LOC > 30 min for moderate-to-severe TBI. However, in experimental TBI models, there is no standard guideline for assessing the severity of TBI. One commonly used metric is the loss of righting reflex (LRR), a rodent analogue of LOC. However, LRR is highly variable across studies and rodents, making strict numeric cutoffs difficult to define. Instead, LRR may best be used as predictor of symptom development and severity. This review summarizes the current knowledge on the associations between LOC and outcomes after mTBI in humans and between LRR and outcomes after experimental TBI in rodents. In clinical literature, LOC following mTBI is associated with various adverse outcome measures, such as cognitive and memory deficits; psychiatric disorders; physical symptoms; and brain abnormalities associated with the aforementioned impairments. In preclinical studies, longer LRR following TBI is associated with greater motor and sensorimotor impairments; cognitive and memory impairments; peripheral and neuropathology; and physiologic abnormalities. Because of the similarities in associations, LRR in experimental TBI models may serve as a useful proxy for LOC to contribute to the ongoing development of evidence-based personalized treatment strategies for patients sustaining head trauma. Analysis of highly symptomatic rodents may shed light on the biological underpinnings of symptom development after rodent TBI, which may translate to therapeutic targets for mTBI in humans.

Post-Concussion Symptoms Rule: Derivation and Validation of a Clinical Decision Rule for Early Prediction of Persistent Symptoms after a Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is a common problem. Depending on diagnostic criteria, 13 to 62% of those patients develop persistent post-concussion symptoms (PPCS). The main objective of this prospective multi-center study is to derive and validate a clinical decision rule (CDR) for the early prediction of PPCS. Patients aged ≥14 years were included if they presented to one of our seven participating emergency departments (EDs) within 24 h of an mTBI. Clinical data were collected in the ED, and symptom evolution was assessed at 7, 30 and 90 days post-injury using the Rivermead Post-Concussion Questionnaire (RPQ). The primary outcome was PPCS at 90 days after mTBI. A predictive model called the Post-Concussion Symptoms Rule (PoCS Rule) was developed using the methodological standards for CDR. Of the 1083 analyzed patients (471 and 612 for the derivation and validation cohorts, respectively), 15.6% had PPCS. The final model included the following factors assessed in the ED: age, sex, history of prior TBI or mental health disorder, headache in ED, cervical sprain and hemorrhage on computed tomography. The 7-day follow-up identified additional risk factors: headaches, sleep disturbance, fatigue, sensitivity to light, and RPQ ≥21. The PoCS Rule had a sensitivity of 91.4% and 89.6%, a specificity of 53.8% and 44.7% and a negative predictive value of 97.2% and 95.8% in the derivation and validation cohorts, respectively. The PoCS Rule will help emergency physicians quickly stratify the risk of PPCS in mTBI patients and better plan post-discharge resources.

Prevalence of Disability Associated With Head Injury With Loss of Consciousness in Adults in the United States: A Population-Based Study

OBJECTIVE

To provide nationally representative prevalence estimates of disability associated with prior head injury with loss of consciousness in the United States and to examine associations between prior head injury and disability.

METHODS

This was a cross-sectional analysis of 7,390 participants ≥40 years of age in the 2011-2014 National Health and Nutrition Examination Surveys (NHANES). Head injury with loss of consciousness was assessed by self-report. Domains of disability were assessed with a standardized structured questionnaire and measured grip strength. Logistic and linear regression models adjusted for demographic, socioeconomic/behavioral, and medical comorbidity variables were used. Multiple imputation was used to account for missing covariate data.

RESULTS

Mean age of participants was 58 years; 53% were female; 71% were non-Hispanic White; and 16% had a history of head injury with loss of consciousness. Overall, participants with a history of head injury had higher prevalence of disability in at least 1 domain of functioning compared to individuals without head injury (47.4% vs 38.6%, p < 0.001), with the highest prevalence of disability in the domains of mobility and work productivity. In fully adjusted models, head injury was significantly positively associated with disability in all domains assessed on the standardized questionnaire (all p < 0.05). Participants with head injury had greater grip strength (all p < 0.05).

CONCLUSIONS

We found that 47.4% of individuals ≥40 years of age in the United States with a history of head injury are living with disability in at least 1 domain of functioning, corresponding to 11.4 million affected individuals. This significant burden of disability suggests that efforts are needed to improve functioning among individuals with head injury.

Disability Rating Scale in the First Few Weeks After a Severe Traumatic Brain Injury as a Predictor of 6-Month Functional Outcome

BACKGROUND

An early acute marker of long-term neurological outcome would be useful to help guide clinical decision making and therapeutic effectiveness after severe traumatic brain injury (TBI). We investigated the utility of the Disability Rating Scale (DRS) as early as 1 wk after TBI as a predictor of favorable 6-mo Glasgow Outcome Scale extended (GOS-E).

OBJECTIVE

To determine the predictability of a favorable 6-mo GOS-E using the DRS measured during weeks 1 to 4 of injury.

METHODS

The study is a sub analysis of patients enrolled in the Epo Severe TBI Trial (n = 200) to train and validate L1-regularized logistic regression models. DRS was collected at weeks 1 to 4 and GOS-E at 6 mo.

RESULTS

The average area under the receiver operating characteristic curve was 0.82 for the model with baseline demographic and injury severity variables and week 1 DRS and increased to 0.88 when including weekly DRS until week 4.

CONCLUSION

This study suggests that week 1 to 4 DRS may be predictors of favorable 6-mo outcome in severe TBI patients and thus useful both for clinical prognostication as well as surrogate endpoints for adaptive clinical trials.