Early mild traumatic brain injury (mTBI or concussion sustained between 0 and 5 years old) can lead to post-concussive symptoms, behavioral changes, and cognitive difficulties. Although school-age children (6–17 years old) experience similar consequences, severe neuropsychological deficits are not common, and the majority have no persisting symptoms after one month. Thus, there may be value in focusing on what characterizes optimal functioning (or wellness) after mTBI, but this has not been explored in young children. This study documents the evolution and predictors of optimal functioning after early mTBI.

Participants were 190 children aged 18 – 60 months with mTBI (n = 69), orthopedic injury (OI; n = 50), or typical development (TDC; n = 71). Optimal functioning was defined as: (1) no clinically significant behavioral problems; (2) no cognitive difficulties; (3) no persisting post-concussive symptoms; (4) average quality of life or better. Predictors related to sociodemographic, injury, child, and caregiver characteristics included number of acute symptoms, child sex, age, temperament, maternal education, parent-child attachment and interaction quality, and parenting stress.

Fewer children with mTBI had optimal functioning over 6 and 18-months post-injury compared to those with OI and TDC. Higher parent-child interaction quality and lower child negative affectivity temperament independently predicted optimal functioning.

Children who sustain early mTBI are less likely to exhibit optimal functioning than their peers in the long-term. Parent-child interaction quality could be a potential intervention target for promoting optimal function.

Symptoms and cognition are both utilized as indicators of recovery following pediatric concussion, yet their interrelationship is not well understood. This study aimed to investigate: 1) the association of post-concussion symptom burden and cognitive outcomes (processing speed and executive functioning [EF]) at 4 and 12 weeks after pediatric concussion, and 2) the moderating effect of sex on this association.

This prospective, multicenter cohort study included participants aged 5.00–17.99 years with acute concussion presenting to four Emergency Departments of the Pediatric Emergency Research Canada network. Five processing speed and EF tasks and the Post-Concussion Symptom Inventory (PCSI; symptom burden, defined as the difference between post-injury and retrospective [pre-injury] scores) were administered at 4 and 12 weeks post-concussion. Generalized least squares models were conducted with task performances as dependent variables and PCSI and PCSI*sex interaction as the main predictors, with important pre-injury demographic and injury characteristics as covariates.

311 children (65.0% males; median age = 11.92 [IQR = 9.14–14.21 years]) were included in the analysis. After adjusting for covariates, higher symptom burden was associated with lower Backward Digit Span (χ2 = 9.85, p = .043) and Verbal Fluency scores (χ2 = 10.48, p = .033) across time points; these associations were not moderated by sex, ps ≥ .20. Symptom burden was not associated with performance on the Coding, Continuous Performance Test, and Color-Word Interference scores, ps ≥ .17.

Higher symptom burden is associated with lower working memory and cognitive flexibility following pediatric concussion, yet these associations were not moderated by sex. Findings may inform concussion management by emphasizing the importance of multifaceted assessments of EF.

Cognitive symptoms are associated with return to work, healthcare use and quality of life after mild traumatic brain injury (mTBI). Additionally, while overall ‘post-concussion’ symptoms are often present at similar levels in mTBI and control groups, cognitive complaints may be specifically elevated in mTBI. A systematic review and meta-analysis was conducted to investigate the frequency and extent of cognitive complaints following adult civilian mTBI, and compare it to the frequency and extent of complaints in control populations (PROSPERO: CRD42020151284).

This review included studies published up to March 2022. Thirteen studies were included in the systematic review, and six were included in the meta-analysis. Data extraction and quality assessment were conducted by two independent reviewers.

Cognitive complaints are common after mTBI, although reported rates differed greatly across studies. Results suggested that mTBI groups report cognitive complaints to a significantly greater extent than control groups (Hedges’ g = 0.85, 95% CI 0.31–1.40, p = .0102). Heterogeneity between studies was high (τ2 = 0.20, 95% CI 0.04–1.58; I2 = 75.0%, 95% CI 43.4%–89.0%). Between-group differences in symptom reporting were most often found when healthy rather than injured controls were employed.

Cognitive complaints are consistently reported after mTBI, and are present at greater levels in mTBI patients than in controls. Despite the importance of these complaints, including in regards to return to work, healthcare use and quality of life, there has been limited research in this area, and heterogeneity in research methodology is common.

Early reporting of atypical symptoms following a mild traumatic brain injury (mTBI) may be an early indicator of poor prognosis. This study aimed to determine the percentage of people reporting atypical symptoms 1-month post-mTBI and explore links to recovery 12 months later in a community-dwelling mTBI sample.

Adult participants (>16 years) who had experienced a mTBI were identified from a longitudinal incidence study (BIONIC). At 1-month post-injury, 260 participants completed the Rivermead Post-Concussion Symptoms Questionnaire (typical symptoms) plus four atypical symptom items (hemiplegia, difficulty swallowing, digestion problems and difficulties with fine motor tasks). At 12 months post-injury, 73.9% (n = 193) rated their overall recovery on a 100-point scale. An ordinal regression explored the association between atypical symptoms at 1 month and recovery at 12 months post-injury (low = 0–80, moderate = 81–99 and complete recovery = 100), whilst controlling for age, sex, rehabilitation received, ethnicity, mental and physical comorbidities and additional injuries sustained at the time of injury.

At 1-month post-injury <1% of participants reported hemiplegia, 5.4% difficulty swallowing, 10% digestion problems and 15.4% difficulties with fine motor tasks. The ordinal regression model revealed atypical symptoms were not significant predictors of self-rated recovery at 12 months. Older age at injury and higher typical symptoms at 1 month were independently associated with poorer recovery at 12 months, p < 0.01.

Atypical symptoms on initial presentation were not linked to global self-reported recovery at 12 months. Age at injury and typical symptoms are stronger early indicators of longer-term prognosis. Further research is needed to determine if atypical symptoms predict other outcomes following mTBI.

Mild traumatic brain injury (mTBI) symptoms are typically assessed via questionnaires in research, yet questionnaires may be more prone to biases than direct clinical interviews. We compared mTBI symptoms reported on two widely used self-report inventories and the novel Structured Interview of TBI Symptoms (SITS). Second, we explored the association between acquiescence response bias and symptom reporting across modes of assessment.

Level 1 trauma center patients with mTBI (N = 73) were recruited within 2 weeks of injury, assessed at 3 months post-TBI, and produced nonacquiescent profiles. Assessments collected included the SITS (comprising open-ended and closed-ended questions), Rivermead Post Concussion Symptoms Questionnaire (RPQ), Sport Concussion Assessment Tool-3 (SCAT-3) symptom checklist, and Minnesota Multiphasic Personality Inventory-2 Restructured Form True Response Inconsistency (TRIN-r) scale.

Current mTBI symptom burden and individual symptom endorsement were highly concordant between SITS closed-ended questions, the RPQ, and the SCAT-3. Within the SITS, participants reported significantly fewer mTBI symptoms to open-ended as compared to later closed-ended questions, and this difference was weakly correlated with TRIN-r. Symptom scales were weakly associated with TRIN-r.

mTBI symptom reporting varies primarily by whether questioning is open- vs. closed-ended but not by mode of assessment (interview, questionnaire). Acquiescence response bias appears to play a measurable but small role in mTBI symptom reporting overall and the degree to which participants report more symptoms to closed- than open-ended questioning. These findings have important implications for mTBI research and support the validity of widely used TBI symptom inventories.

Recent studies suggest that close-range blast exposure (CBE), regardless of acute concussive symptoms, may have negative long-term effects on brain health and cognition; however, these effects are highly variable across individuals. One potential genetic risk factor that may impact recovery and explain the heterogeneity of blast injury’s long-term cognitive outcomes is the inheritance of an apolipoprotein (APOE) ε4 allele, a well-known genetic risk factor for Alzheimer’s disease. We hypothesized that APOE ε4 carrier status would moderate the impact of CBE on long-term cognitive outcomes.

To test this hypothesis, we examined 488 post-9/11 veterans who completed assessments of neuropsychological functioning, psychiatric diagnoses, history of blast exposure, military and non-military mild traumatic brain injuries (mTBIs), and available APOE genotypes. We separately examined the effects of CBE on attention, memory, and executive functioning in individuals with and without the APOE ε4 allele.

As predicted, we observed a differential impact of CBE status on cognition as a function of APOE ε4 status, in which CBE ε4 carriers displayed significantly worse neuropsychological performance, specifically in the domain of memory. These results persisted after adjusting for clinical, demographic, and genetic factors and were not observed when examining other neurotrauma variables (i.e., lifetime or military mTBI, distant blast exposure), though these variables displayed similar trends.

These results suggest APOE ε4 carriers are more vulnerable to the impact of CBE on cognition and highlight the importance of considering genetic risk when studying cognitive effects of neurotrauma.

To evaluate an abbreviated NIH Toolbox Cognition Battery (NIHTB-CB) protocol that can be administered remotely without any in-person assessments, and explore the agreement between prorated scores from the abbreviated protocol and standard scores from the full protocol.

Participant-level age-corrected NIHTB-CB data were extracted from six studies in individuals with a history of stroke, mild traumatic brain injury (mTBI), treatment-resistant psychosis, and healthy controls, with testing administered under standard conditions. Prorated fluid and total cognition scores were estimated using regression equations that excluded the three fluid cognition NIHTB-CB instruments which cannot be administered remotely. Paired t tests and intraclass correlations (ICCs) were used to compare the standard and prorated scores.

Data were available for 245 participants. For fluid cognition, overall prorated scores were higher than standard scores (mean difference = +4.5, SD = 14.3; p < 0.001; ICC = 0.86). For total cognition, overall prorated scores were higher than standard scores (mean difference = +2.7, SD = 8.3; p < 0.001; ICC = 0.88). These differences were significant in the stroke and mTBI groups, but not in the healthy control or psychosis groups.

Prorated scores from an abbreviated NIHTB-CB protocol are not a valid replacement for the scores from the standard protocol. Alternative approaches to administering the full protocol, or corrections to scoring of the abbreviated protocol, require further study and validation.

The Cognition Battery of the National Institute of Health (NIH) Toolbox for Assessment of Neurological and Behavioural Function is a computerised neuropsychological battery recommended for clinical practice, neurological research and clinical trials. We investigated the utility of the NIH Toolbox Cognition Battery (NIHTB-CB) for people with concussion.

In this small qualitative study, semi-structured interviews were conducted with five adults with concussion who were participating in a larger study using the NIHTB-CB. Three clinician participants and two cultural advisors familiar with the tool were also interviewed. Interview transcripts were analysed using a general thematic approach and qualitative description.

Participants described both positive and negative experiences with the NIHTB-CB and using qualitative description, their experiences were organised into three broad themes: (1) using technology for cognitive testing made sense, (2) there were some cultural relevance questions and (3) cognitive testing after concussion could have challenges. They were positive about the computerised format and range of domains assessed for the concussion context but identified the contextual relevance of some content as having potential to impact on performances.

This was a small study examining the experiences of a select group of participants, but nevertheless does suggest a need for future research validating the NIHTB-CB for use in different cultural and clinical contexts.

In response to advancing clinical practice guidelines regarding concussion management, service members, like athletes, complete a baseline assessment prior to participating in high-risk activities. While several studies have established test stability in athletes, no investigation to date has examined the stability of baseline assessment scores in military cadets. The objective of this study was to assess the test–retest reliability of a baseline concussion test battery in cadets at U.S. Service Academies.

All cadets participating in the Concussion Assessment, Research, and Education (CARE) Consortium investigation completed a standard baseline battery that included memory, balance, symptom, and neurocognitive assessments. Annual baseline testing was completed during the first 3 years of the study. A two-way mixed-model analysis of variance (intraclass correlation coefficent (ICC)3,1) and Kappa statistics were used to assess the stability of the metrics at 1-year and 2-year time intervals.

ICC values for the 1-year test interval ranged from 0.28 to 0.67 and from 0.15 to 0.57 for the 2-year interval. Kappa values ranged from 0.16 to 0.21 for the 1-year interval and from 0.29 to 0.31 for the 2-year test interval. Across all measures, the observed effects were small, ranging from 0.01 to 0.44.

This investigation noted less than optimal reliability for the most common concussion baseline assessments. While none of the assessments met or exceeded the accepted clinical threshold, the effect sizes were relatively small suggesting an overlap in performance from year-to-year. As such, baseline assessments beyond the initial evaluation in cadets are not essential but could aid concussion diagnosis.

The long-term effects of pediatric concussion on white matter microstructure are poorly understood. This study investigated long-term changes in white matter diffusion properties of the corpus callosum in youth several years after concussion.

Participants were 8–19 years old with a history of concussion (n = 36) or orthopedic injury (OI) (n = 21). Mean time since injury for the sample was 2.6 years (SD = 1.6). Participants underwent diffusion magnetic resonance imaging, completed cognitive testing, and rated their post-concussion symptoms. Measures of diffusivity (fractional anisotropy, mean, axial, and radial diffusivity) were extracted from white matter tracts in the genu, body, and splenium regions of the corpus callosum. The genu and splenium tracts were further subdivided into 21 equally spaced regions along the tract and diffusion values were extracted from each of these smaller regions.

White matter tracts in the genu, body, and splenium did not differ in diffusivity properties between youth with a history of concussion and those with a history of OI. No significant group differences were found in subdivisions of the genu and splenium after correcting for multiple comparisons. Diffusion metrics did not significantly correlate with symptom reports or cognitive performance.

These findings suggest that at approximately 2.5 years post-injury, youth with prior concussion do not have differences in their corpus callosum microstructure compared to youth with OI. Although these results are promising from the perspective of long-term recovery, further research utilizing longitudinal study designs is needed to confirm the long-term effects of pediatric concussion on white matter microstructure.

Involving stakeholders has been acknowledged as a way to improve quality and relevance in health research. The mechanisms that support effective research engagement with stakeholders have not been studied in the area of concussion. Concussion is a large public health concern worldwide with billions of dollars spent on health care services and research with improvements in care and service delivery not moving forward as quickly as desired. Enabling effective stakeholder engagement could improve concussion research and care.

The aim of the study was to identify potential benefits, challenges, and motivators to engaging in research by gathering the perspectives of adults with lived experience of concussion.

A thematic analysis of qualitative responses collected from a convenience sample attending a provincial brain injury conference (n = 60) was undertaken using open coding followed by axial coding.

Four themes regarding benefits to engagement emerged: first-hand account, meaningful recovery, research relevance, and better understanding of gaps. Three forces inhibited engagement: environmental barriers, injury-related constraints, and personal deterrents. Four enablers supported engagement: focus on positive impact, build connections, create a supportive environment, and provide financial assistance.

Understanding stakeholder’s perspectives on research engagement is an important issue that may serve to improve research quality. There may be unique nuances at play with injury-specific stakeholders that require researchers to consider a balance between reducing inhibitors while supporting enablers. These findings are preliminary and limited. Nevertheless, they provide needed insight and guidance for ongoing investigation regarding improvement of stakeholder engagement in concussion research.

Emerging data suggest that recovery from mild traumatic brain injury (mTBI) takes longer than previously thought. This paper examines trajectories for cognitive recovery up to 48 months post-mTBI, presenting these visually using a Sankey diagram and growth curve analysis.

This sample (n = 301) represents adults (≥16 years) from a population-based Brain Injury Outcomes in the New Zealand Community study over a 4-year follow-up on the CNS-Vital Signs neuropsychological test. Data were collected within 2 weeks of injury, and then at 1, 6, 12 and 48 months post-injury.

Significant improvement in cognitive functioning was seen up to 6 months post-injury. Using growth curve modelling, we found significant improvements in overall neurocognition from baseline to 6 months, on average participants improved one point per month (0.9; 95% CI 0.42–1.39) p < 0.001. No change in neurocognition was found within the time periods 6–12 months or 12–48 months. The Sankey highlighted that at each time point, a small proportion of participants remained unchanged or declined. Proportionally, few show any improvement after the first 6 months.

Most individuals remained stable or improved over time to 6 months post-injury. Summary statistics are informative regarding overall trends, but can mask differing trajectories for recovery. The Sankey diagram indicates that not all improve, as well as the potential impact of individuals moving in and out of the study. The Sankey diagram also indicated the level of functioning of those most likely to withdraw, allowing targeting of retention strategies.