Neuropsychological performance following a history of multiple self-reported concussions: a meta-analysis

Critical Review of Recently Published Studies Claiming Long-Term Neurocognitive Abnormalities in Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common claimed personal injury condition for which neuropsychologists are retained as forensic experts in litigation. Therefore, it is critical that experts have accurate information when testifying as to neurocognitive outcome from concussion. Systematic reviews and six meta-analyses from 1997 to 2011 regarding objective neurocognitive outcome from mTBI provide no evidence that concussed individuals do not return to baseline by weeks to months post-injury. In the current manuscript, a critical review was conducted of 21 research studies published since the last meta-analysis in 2011 that have claimed to demonstrate long-term (i.e., ≥12 months post-injury) neurocognitive abnormalities in adults with mTBI. Using seven proposed methodological criteria for research investigating neurocognitive outcome from mTBI, no studies were found to be scientifically adequate. In particular, more than 50% of the 21 studies reporting cognitive dysfunction did not appropriately diagnose mTBI, employ prospective research designs, use standard neuropsychological tests, include appropriate control groups, provide information on motive to feign or use PVTs, or exclude, or adequately consider the impact of, comorbid conditions known to impact neurocognitive scores. We additionally analyzed 15 studies published during the same period that documented no longer term mTBI-related cognitive abnormalities, and demonstrate that they were generally more methodologically robust than the studies purporting to document cognitive dysfunction. The original meta-analytic conclusions remain the most empirically-sound evidence informing our current understanding of favorable outcomes following mTBI.

Co-Occurrence of Traumatic Brain Injury and Post-Traumatic Stress Disorder in a National Sample of UK Police Officers: Impact on Social Well-Being and Employment Outcomes

OBJECTIVE

To determine the lifetime prevalence of traumatic brain injury (TBI) in UK police officers and evaluate associations between mild TBI (mTBI), persistent post-concussion-like symptoms (PPCS), post-traumatic stress disorder (PTSD) and complex PTSD (C-PTSD).

SETTING

Online survey of serving police officers across England, Scotland and Wales.

PARTICIPANTS

A total of 617 currently serving police officers were eligible for the study and the final sample consisted of 573 participants. Subgroup comparisons were made between individuals with no TBI history (n = 355), a single mTBI (n = 88) and multiple mTBIs (n = 130).

DESIGN

Cross-sectional survey assessing lifetime history of TBI, PPCS and PTSD symptoms.

MAIN MEASURES

Lifetime TBI prevalence was assessed with the Ohio State TBI-Identification Method. Post-concussion-like symptoms were evaluated with the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and PTSD/C-PTSD were measured using the International Trauma Questionnaire.

RESULTS

Lifetime prevalence of TBI was 38% (n = 234), with 23% reporting multiple TBIs. One-way ANOVAs demonstrated that individuals with multiple TBIs exhibited significantly greater cognitive (unadjusted R2 = .02, P = .001) and somatic symptoms (unadjusted R2 = .02, P < .001) and reported more severe total RPQ symptoms (unadjusted R2 = .02, P = .009) compared to those without mTBI history. Multiple TBI history was associated with increased severity across all PTSD/C-PTSD domains (P < .004), and a significantly higher C-PTSD prevalence (P = .001). These results remained significant in ANCOVAs, adjusting for demographic, occupational and trauma-exposure variables (P < .04).

CONCLUSIONS

Comorbidity between TBI and C-PTSD is prevalent in this sample of police officers. Symptom endorsement is additive in those with mTBI history, this could lead to risk to employment, relationship breakdown, and further mental health problems. Routine occupational health checks should monitor both TBI and associated symptoms over time. If necessary, police officers with head or neck injuries should follow a graduated return-to-duty protocol, including a gradual increase in activity level and appropriate mental health intervention.

Identifying the 'Miserable Minority' Among Pediatric Patients Following Concussion

OBJECTIVES

To investigate whether there are empirically-detectable subgroups of concussion severity and recovery across three consecutive concussions, as well as to define risk factor and clinical assessment differences across subgroups.

METHODS

The present study was a retrospective chart review of 202 adolescents 13.17 ± 1.99 years old who presented to a concussion specialty clinic within 30 days of injury for multiple injuries between 2019 and 2020. Participants included patients from a specialty clinic for two (n = 202) or three (n = 68) total concussions. Latent class analysis (LCA) was used to identify subgroups based upon concussion symptom severity and recovery time. Risk factors (sex, age at first injury, and histories of anxiety, depression, migraine, motion sickness, ocular dysfunction, and attention-deficit/hyperactivity disorder [ADHD] or learning disability [LD]) were compared across subgroups.

RESULTS

A two-class solution yielded one group of 163 participants characterized by lower symptoms and shorter recovery times (80.7%, "normal") and 39 participants (19.3%, "miserable minority") characterized by higher symptoms and longer recovery times. Only female sex (OR = 4.91, p = 0.005) was a significant predictor of class membership. The miserable group presented for treatment nearly 4 days later (9.41 days) compared to the normal group (5.74 days) for the first injury, and almost 2 days later for the second injury (7.33 vs 5.26 days).

CONCLUSIONS

Approximately 1 in 5 patients who presented to a concussion specialty clinic for a repeat concussion were classified in the miserable minority subgroup. This subgroup was characterized by markedly higher initial symptom burdens and over double the recovery time.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III evidence.

A review of long-term outcomes of repetitive concussive and subconcussive blast exposures in the military and limitations of the literature

Objective: The purpose of this review is to summarize the long-term cognitive, psychological, fluid biomarker, and neuroimaging outcomes following repetitive concussive and subconcussive blast exposures sustained through a military career. Method/Results: A review of the literature was conducted, with 450 manuscripts originally identified and 44 manuscripts ultimately included in the review. The most robust studies investigating how repetitive concussive and subconcussive exposures related to cognitive performance suggest there is no meaningful impact. Although there are minimal studies that suggest some small impacts on neuroimaging and fluid biomarkers, most findings have been in very small samples and fail to replicate. Both repetitive blast mTBI and subconcussive blasts appeared to be associated with increased self-reported symptoms. Many of the studies suffered from small sample size, failure to correct for multiple comparisons, and inappropriate control groups. Conclusions: Overall, there is little evidence to support that repetitive blast mTBIs or subconcussive blast exposures have a lasting impact on cognition, neuroimaging, or fluid biomarkers. In contrast, there does appear to be a relationship between these exposures and self-reported psychological functioning, though it is unclear what mechanism drives this relationship. Small sample size, lack of correction for multiple comparisons, limited control groups, lack of consideration of important covariates, limited diversity of samples, and lack of reliable and valid measures for assessment of blast exposure are major limitations restricting this research. Patients should be encouraged that while research is ongoing, there is little to currently suggest long-term cognitive or neurological damage following repetitive blast exposure.

Long-term effects of concussion on attention, sensory gating and motor learning

The current work aimed to understand the behavioral manifestations that result from disruptions to the selective facilitation of task-relevant sensory information at early cortical processing stages in those with a history of concussion. A total of 40 participants were recruited to participate in this study, with 25 in the concussion history group (Hx) and 15 in the control group (No-Hx). Somatosensory-evoked potentials (SEPs) were elicited via median nerve stimulation while subjects performed a task that manipulated their focus of attention toward or away from proprioceptive cues. Participants also completed an implicit motor sequence learning task relying solely on proprioceptive cues, as well as a visual attentional blink (AB) task to understand the effect of concussion on rapid shifts in attention. The Hx SEP data replicated past work showing an absence of relevancy-based facilitation at early cortical processing stages (N20-P27) that emerged at later processing stages. Our Hx showed evidence of relevancy-based facilitation at either the P50-N70 or the N70-P100. Performance on the learning task was not significantly different between the Hx and No-Hx. Performance on the AB task revealed greater AB magnitude in the Hx compared to the No-Hx. Collectively, these results suggest a compensatory strategy in the Hx that enables them to learn to the same degree as controls. However, when the attentional system is taxed with high temporal demands there are decrements in performance. These results are of particular importance given that these individuals are at an increased risk of sustaining subsequent concussions, and musculoskeletal injuries.

Processing speed and its association with working memory and episodic memory 3-6 months after pediatric mild traumatic brain injury

OBJECTIVE

Following mild traumatic brain injury (mTBI), children show reduced processing speed (PS). Evidence suggests that slowed PS after TBI is associated with working memory deficits. Our aim was to investigate several forms of PS and to examine its impact on working and episodic memory performance in children after mTBI.

METHOD

We included data of 64 children after mTBI and 57 healthy control children aged 8-16 years. PS (Color Naming, Coding, Symbol Search, Alertness) was compared between groups 1 week (T1) and 3-6 months (T2) after the injury; working and episodic memory outcome was compared between groups at T2.

RESULTS

Alertness at T1 and Color Naming at T1 and T2 were significantly reduced following mTBI compared to controls, although most group differences in PS disappeared when patients with previous impairments and mTBI were excluded. PS was predictive for episodic and working memory performance 3-6 months after injury, whereas group was a significant predictor of working memory.

CONCLUSIONS

Compared to healthy controls, children after mTBI showed reduced performance in verbal PS, which was associated with working memory. In children who are symptomatic after mTBI, diagnostic screening of PS could be helpful in identifying patients that could profit from speed-improving strategies.

Disentangling subjective symptom complaints and objective cognitive performance in veterans: Impact of posttraumatic stress disorder and lifetime traumatic brain injury burden

Self-reported histories of mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) symptoms are prevalent among post-9/11 veterans. Both are associated with subjective and often overlapping symptom complaints, but variably with objective neuropsychological test performances. These outcomes are seldom explored in relation to lifetime mTBI burden. This cross-sectional study examined associations of PTSD and lifetime mTBI with subjective (persistent symptoms after concussion and cognitive complaints) and objective (performances across five cognitive domains) measures among 46 veterans. Within this sample, 20 veterans had Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) confirmed PTSD (PTSD+), whereas 26 demographically-similar participants did not meet criteria (PTSD-). The Boston Assessment of Traumatic Brain Injury-Lifetime (BAT-L) yielded total mTBI scores ranging from 0 to 8. Regressions showed PTSD was associated with increased subjective symptoms/cognitive complaints, along with reduced verbal fluency, visuospatial memory, and processing speed performances. Lifetime mTBI burden was associated with subjective symptoms, but not with objective cognitive test performance, after controlling for PTSD. No significant interactions were observed. Exploratory correlations suggested that all PTSD symptom clusters were generally associated with the subjective and objective measures. However, fewer significant associations emerged within the PTSD+/- groups separately, with each group yielding somewhat different patterns of relationships. PTSD and increasing mTBI burden are consistently associated with negative subjective symptoms, including cognitive complaints. Each condition likely explains some degree of unique variance in symptom reporting. PTSD is associated with poorer objective cognition on some tasks, including processing speed, executive functioning, and learning/memory. Implications are explored.

The Interval Between Concussions Does Not Influence Time to Asymptomatic or Return to Play: A CARE Consortium Study

INTRODUCTION

The purpose of this study was to determine if the time interval between two concussive events influences the number of days to asymptomatic status, days to return to play, or performance on common post-concussion assessments following the second concussion.

METHODS

Data from 448 collegiate athletes and service academy cadets with two concussions (time between concussions: median 295.0 days [interquartile range: 125.0-438.2]), 40.0% female) were analyzed from Concussion Assessment Research and Education (CARE) Consortium institutions between 2014 and 2020. Days between concussions was the primary predictor variable. Primary outcome measures included time to asymptomatic and time to return to play following the second concussion. Secondary outcome measures included total number of symptoms, total symptom severity, Balance Error Scoring System total score, and Standardized Assessment of Concussion total score within 48 h of their second concussion.

RESULTS

Time between concussions did not significantly contribute to the multivariate time to asymptomatic (p = 0.390), time to return to play (p = 0.859), or the secondary outcomes (p-range = 0.165-0.477) models. Time to asymptomatic (p = 0.619) or return to play (p = 0.524) did not differ between same-season and different-season concussions. Sex significantly contributed to the return to play (p = 0.005) multivariate model. Delayed symptom onset and immediate removal from play/competition significantly contributed to the total number of symptoms (p = 0.001, p = 0.014) and symptom severity (p = 0.011, p = 0.022) multivariate models.

CONCLUSION

These results suggest that in a population with a large period between injuries, the time between concussions may not be relevant to clinical recovery.

Listening to the Voices of Aboriginal and Torres Strait Islander Women in Regional and Remote Australia About Traumatic Brain Injury From Family Violence: A Qualitative Study

INTRODUCTION

Indigenous women experience high rates of family violence-related head injuries. At present, lived experience accounts from Indigenous women are absent, which results in incomplete understandings and inadequate responses that have detrimental impacts on them and their families. The aim of this study was to gain insight into Indigenous women's personal and family perspectives regarding violence-related traumatic brain injury (TBI), including impacts on life, as well as decision-making processes about healthcare access and engagement.

METHODS

Purposeful sampling was used to complete semi-structured interviews with 18 Indigenous women living in regional and remote Australia who had experienced TBI from family violence. The data from these interviews were augmented by data from interviews and focus groups with 28 community members, including family members or carers of Indigenous women living with TBI from family violence.

RESULTS

Three themes were conceptualised based on the data and research aims: interweaving of the past and the present-ways women experience brain injury; factors that inform decision-making to access healthcare; and managing everyday changes that result from TBI from family violence. Indigenous women described living with a range of symptoms following repeated head injuries including problems with memory, cognition and concentration. A range of strategies to manage long-term symptoms of TBI were used by Indigenous women and when they did seek healthcare, Indigenous women were required to navigate a range of barriers.

CONCLUSIONS

The findings identify a range of gaps in healthcare and housing supports for Indigenous women with TBI from violence, highlighting the significant investment needed to develop responsive and appropriate pathways of care in regional and remote areas. A range of suggestions are discussed including development of a specialised workforce who can provide apppropriate follow-up support, co-designed concussion clinics and educational resources. TBI must also be a key aspect of policy and practice for services working with Indigenous women who have experienced violence to ensure appropriate responses are provided.

PUBLIC OR PATIENT CONTRIBUTION

Indigenous women shared their views and experiences of TBI from family violence as well as decision-making about accessing healthcare and managing TBI symptoms. As such, study participants provided public contributions to the research.

STEP-Home transdiagnostic group reintegration workshop to improve mental health outcomes for post-9/11 Veterans: Design, methods, and rationale for a randomized controlled behavioral trial

BACKGROUND

Many post-9/11 U.S. combat Veterans experience difficulty readjusting to civilian life after military service, including relationship problems, reduced work productivity, substance misuse, and increased anger control problems. Mental health problems are frequently cited as causing these difficulties, driven by unparalleled rates of mild traumatic brain injury, posttraumatic stress, and other co-occurring emotional and physical conditions. Given the high prevalence of multimorbidity in this cohort, acceptable, non-stigmatizing, transdiagnostic interventions targeting reintegration are needed. The STEP-Home reintegration workshop has the potential to significantly improve skills to foster civilian reintegration, increase engagement in VA services, and improve mental health outcomes in Veterans with and without diagnosed clinical conditions.

METHODS/DESIGN

Ongoing from 2019, a prospective, two-site, randomized trial of 206 post-9/11 U.S. military Veterans randomized to receive either 12 sessions of the STEP-Home transdiagnostic reintegration workshop (SH; Active Intervention) or Present Centered Reintegration Group Therapy (PCRGT; Active Control Intervention). Primary outcomes are reintegration, anger, and emotional regulation post-intervention and at 3-months post-intervention. Secondary outcomes include measures of mental health, functional and vocational status, and cognition.

CONCLUSION

This study addresses an important gap in transdiagnostic interventions to improve civilian reintegration in post-9/11 Veterans. STEP-Home is designed to promote treatment engagement and retention, opening the door to critically needed VA care, and ultimately reducing long-term healthcare burden of untreated mental health illness in U.S. Veterans.

TRIAL REGISTRATION

Clinicaltrials.gov: D2907-R.

Cause of Concussion With Persisting Symptoms Is Associated With Long-Term Recovery and Symptom Type, Duration, and Number in a Longitudinal Cohort of 600 Patients

It is important for patients and clinicians to know the potential for recovery from concussion as soon as possible after injury, especially in patients who do not recover completely in the first month and have concussion with persisting concussion symptoms (C+PCS). We assessed the association between the causes of concussion and recovery from C+PCS in a consecutive retrospective and prospective cohort of 600 patients referred to the Canadian Concussion Center (CCC) at Toronto Western Hospital. Data were obtained from clinical records and follow-up questionnaires and not from a standardized database. A novel method was used to assess long-term recovery, and multi-variable Cox proportional hazards models were used to assess relationships between cause of concussion and time to recovery. We examined the subsequent recovery of patients who had not recovered after at least one month from the time of concussion. Patients were grouped into the following four causes: sports and recreation (S&R, n = 312, 52%); motor vehicle collisions (MVC, n = 103, 17%); falls (n = 100, 17%); and being struck by an object including violence (SBOV, n = 85, 14%). The MVC group had the highest percentage of females (75.7%), the oldest participants (median: 40.0 [interquartile range (IQR):30.5-49.0] years), the most symptoms (median:11.0 [IQR:8.5-15.0]), and the longest symptom duration (median: 28.0 [IQR:12.0-56.00] months). In contrast, the S&R group had the highest percentage of males (58.1%), the youngest participants (median:20.0 [IQR:17.0-30.0] years), the best recovery outcome, and shortest symptom duration (median:22.0 [IQR:8.0-49.5] months). Significant differences among the four causes included age (p < 0.001), sex (p < 0.001), number of previous concussions (p < 0.001), history of psychiatric disorders (p = 0.002), and migraine (p = 0.001). Recovery from concussion was categorized into three groups: (1) Complete Recovery occurred in only 60 (10%) patients with median time 8.0 (IQR:3.5-18.0) months and included 42 S&R, 7 MVC, 8 falls, and 3 SBOV; (2) Incomplete Recovery occurred in 408 (68.0%) patients with persisting median symptom time of 5.0 (IQR:2.0-12.0) months; and (3) Unknown Recovery occurred in 132 (22.0%) patients and was because of lack of follow-up. In summary, the cause of C+PCS was associated with the type, number, and duration of symptoms and time required for recovery, although all causes of C+PCS produced prolonged symptoms in a large percentage of patients, which emphasizes the importance of concussions as a public health concern necessitating improved prevention and treatment strategies.

DNALI1 Promotes Neurodegeneration after Traumatic Brain Injury via Inhibition of Autophagosome-Lysosome Fusion

Traumatic brain injury (TBI) leads to progressive neurodegeneration that may be caused by chronic traumatic encephalopathy (CTE). However, the precise mechanism remains unclear. Herein, the study identifies a crucial protein, axonemal dynein light intermediate polypeptide 1 (DNALI1), and elucidated its potential pathogenic role in post-TBI neurodegeneration. The DNALI1 gene is systematically screened through analyses of Aging, Dementia, and TBI studies, confirming its elevated expression both in vitro and in vivo. Moreover, it is observed that altered DNALI1 expression under normal conditions has no discernible effect. However, upon overexpression, DNALI1 inhibits autophagosome-lysosome fusion, reduces autophagic flux, and exacerbates cell death under pathological conditions. DNALI1 silencing significantly enhances autophagic flux and alleviates neurodegeneration in a CTE model. These findings highlight DNALI1 as a potential key target for preventing TBI-related neurodegeneration.

Associations of Prior Head Injury With Mild Behavioral Impairment Domains

OBJECTIVE

This study investigated associations of prior head injury and number of prior head injuries with mild behavioral impairment (MBI) domains.

SETTING

The Atherosclerosis Risk in Communities (ARIC) Study.

PARTICIPANTS

A total of 2534 community-dwelling older adults who took part in the ARIC Neurocognitive Study stage 2 examination were included.

DESIGN

This was a prospective cohort study. Head injury was defined using self-reported and International Classification of Diseases, Ninth Revision ( ICD -9) code data. MBI domains were defined using the Neuropsychiatric Inventory Questionnaire (NPI-Q) via an established algorithm mapping noncognitive neuropsychiatric symptoms to the 6 domains of decreased motivation, affective dysregulation, impulse dyscontrol, social inappropriateness, and abnormal perception/thought content.

MAIN MEASURES

The primary outcome was the presence of impairment in MBI domains.

RESULTS

Participants were a mean age of 76 years, with a median time from first head injury to NPI-Q administration of 32 years. The age-adjusted prevalence of symptoms in any 1+ MBI domains was significantly higher among individuals with versus without prior head injury (31.3% vs 26.0%, P = .027). In adjusted models, a history of 2+ head injuries, but not 1 prior head injury, was associated with increased odds of impairment in affective dysregulation and impulse dyscontrol domains, compared with no history of head injury (odds ratio [OR] = 1.83, 95% CI = 1.13-2.98, and OR = 1.74, 95% CI = 1.08-2.78, respectively). Prior head injury was not associated with symptoms in MBI domains of decreased motivation, social inappropriateness, and abnormal perception/thought content (all P > .05).

CONCLUSION

Prior head injury in older adults was associated with greater MBI domain symptoms, specifically affective dysregulation and impulse dyscontrol. Our results suggest that the construct of MBI can be used to systematically examine the noncognitive neuropsychiatric sequelae of head injury; further studies are needed to examine whether the systematic identification and rapid treatment of neuropsychiatric symptoms after head injury is associated with improved outcomes.

Repetitive Head Injury and Cognitive, Physical, and Emotional Symptoms in Women Survivors of Intimate Partner Violence

Many women survivors of intimate partner violence (IPV) experience repetitive head injuries in their lifetime, but limited research has examined the cumulative effects of multiple head injuries on post-concussion symptom severity in this population. This study examined how number of lifetime head injuries and episodes of loss of consciousness (LOC) due to head injuries were related to current cognitive, physical, and emotional symptoms among women survivors of IPV. Cisgender women from Kentucky were recruited following a protective order against an intimate partner, including 268 women with no reported lifetime head injuries and 250 women with one or more IPV-related head injuries (mean [M] = 17.2 head injuries, standard deviation [SD] = 50.5, median [Mdn] = 4, range = 1-515; M = 1.8 LOC episodes, SD = 4.3, Mdn = 1, range = 0-35, respectively). Participants underwent in-person interviews about lifetime physical and sexual IPV history, head injury history, and current cognitive, physical, and emotional symptoms. Sociodemographic characteristics, physical and sexual IPV severity, and current symptom severity were examined in relation to number of head injuries and LOC episodes. A higher number of head injuries was associated with greater age, White race, less than high school education, unemployment, and rural residence. No sociodemographic variables differed based on number of LOC episodes. Greater number of lifetime head injuries and LOC episodes correlated significantly with physical IPV severity (rho = 0.35, p < 0.001; rho = 0.33, p < 0.001, respectively) and sexual IPV severity (rho = 0.22, p < 0.001; rho = 0.19, p = 0.003). Greater number of head injuries and LOC episodes correlated significantly with greater cognitive (rho = 0.33, p < 0.001; rho = 0.23, p < 0.001, respectively), physical (rho = 0.36, p < 0.001; rho = 0.31, p < 0.001), emotional (rho = 0.36, p < 0.001; rho = 0.18, p = 0.004), and total symptom severity (rho = 0.39, p < 0.001; rho = 0.26, p < 0.001). In group comparisons, participant groups stratified by number of head injuries (i.e., 0, 1-3, 4+) differed in total symptom severity (p < 0.001, η2 = 0.15), with greater symptom burden associated with more head injuries. Participants with and without LOC differed in symptom severity: cognitive (p < 0.001, d = 0.45), physical (p < 0.001, d = 0.60), emotional (p = 0.004, d = 0.37), and total symptom severity (p < 0.001, d = 0.53). Group differences between participants with and without LOC remained significant after controlling for sociodemographic variables and IPV severity. There was no cumulative effect of LOC, in that participants with 1 LOC episode did not differ from participants with 2 + LOC episodes (p > 0.05). Based on hierarchical regression analyses, only physical symptoms were independently related to number of head injuries (p = 0.008, ΔR2 = 0.011) and number of LOC episodes (p = 0.014, ΔR2 = 0.021) after controlling for sociodemographic characteristics and IPV severity. Among women survivors of IPV, cumulative head injuries appear related to greater symptom severity. Greater head injury history was independently related to worse physical symptoms (e.g., headaches, dizziness, sleep problems), whereas cognitive and emotional symptoms were, in part, attributable to cumulative physical and emotional trauma due to IPV. Women survivors of IPV with repetitive head injuries have unmet neurobehavioral health needs that may benefit from targeted interventions.

Traumatic brain injury rehabilitation for warfighters with post-traumatic stress

BACKGROUND

While there is extensive empirical support and clinical guidance for the treatment of mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) individually, less is known about treating the comorbid presentation of both conditions.

OBJECTIVE

The purpose of this review article is to provide information on the mental health treatment needs of service members (SMs) engaged in traumatic brain injury (TBI) rehabilitation. It also aims to offer a framework for an integrated treatment approach to address the cognitive and psychological health needs of warfighters.

METHODS

We review the prevalence and outcomes associated with comorbid TBI and PTSD and present relevant access to care considerations. Additionally, we identify an integrated approach to TBI treatment which takes psychological trauma into consideration. We introduce a trauma-informed care (TIC) model with specified diagnostic and treatment considerations for the service member and veteran (SM/V) communities. TIC is a strengths-based framework that raises the system-wide awareness of treatment facilities to the impact of psychological trauma on behavioral health.

RESULTS

A comprehensive diagnostic approach is recommended with considerations for symptom etiology. Clinical considerations derived from available guidelines are identified to meet critical treatment needs for SM/Vs presenting for TBI treatment with a remote history of mTBI and psychological trauma or known PTSD. Clinical practice guidelines are used to inform an integrated TBI treatment model and maximize rehabilitation efforts for warfighters.

CONCLUSION

Given the prevalence of comorbid TBI and PTSD among SM/Vs and its impact on outcomes, this review presents the integration of appropriate diagnostics and treatment practices, including the incorporation of clinical practice guidelines (CPGs) into TBI rehabilitation.

Prognostic factors for persistent symptoms in adults with mild traumatic brain injury: an overview of systematic reviews

BACKGROUND

Mild traumatic brain injury (mTBI) is an increasing public health problem, because of its persistent symptoms and several functional consequences. Understanding the prognosis of a condition is an important component of clinical decision-making and can help to guide the prevention of persistent symptoms following mTBI. The prognosis of mTBI has stimulated several empirical primary research papers and many systematic reviews leading to the identification of a wide range of factors. We aim to synthesize these factors to get a better understanding of their breadth and scope.

METHODS

We conducted an overview of systematic reviews. We searched in databases systematic reviews synthesizing evidence about the prognosis of persistent symptoms after mTBI in the adult population. Two reviewers independently screened all references and selected eligible reviews based on eligibility criteria. They extracted relevant information using an extraction grid. They also rated independently the risk of bias using the ROBIS tool. We synthesized evidence into a comprehensive conceptual map to facilitate the understanding of prognostic factors that have an impact on persistent post-concussion symptoms.

RESULTS

From the 3857 references retrieved in a database search, we included 25 systematic reviews integrating the results of 312 primary articles published between 1957 and 2019. We examined 35 prognostic factors from the systematics reviews. No single prognostic factor demonstrated convincing and conclusive results. However, age, sex, and multiple concussions showed an affirmatory association with persistent post-concussion outcomes in systematic reviews.

CONCLUSION

We highlighted the need for a comprehensive picture of prognostic factors related to persistent post-concussion symptoms. We believe that these prognostic factors would guide clinical decisions and research related to prevention and intervention regarding persistent post-concussion symptoms.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020176676.

Identifying prioritization criteria for patients with mtbi waiting for multidisciplinary rehabilitation services: A Delphi study

INTRODUCTION

Rehabilitation service providers must take into account prognostic factors when making clinical decisions, which includes using these factors as prioritization criteria. The goal of this study was to establish consensus on patient prioritization criteria based on prognostic factors related to persistent symptoms for patients with mild traumatic brain injury (mTBI) waiting for outpatient specialized rehabilitation services.

MATERIALS AND METHODS

We conducted a Delphi survey involving clinicians, researchers, decision makers, and patients. Before the survey, we presented the results of an overview of systematic reviews summarizing the evidence on prognostic factors related to post-concussion symptoms.

RESULTS

After two rounds, the 17 experts reached consensus on the inclusion of 12 prioritization criteria: acute stress disorder, anxiety and depression, baseline mental and physical health, functional impacts and difficulties in performing daily habits after the trauma, motivation to receive services, multiple concussions, prior neurological problems, PTSD, quality of sleep, return to work failures, somatic complaints, suicidal ideation.

CONCLUSION

Healthcare stakeholders must consider a wide range of factors to guide clinical decision-making, including about access to care and patient prioritization. This study shows that the Delphi technique can be used to reach consensus on such decisions regarding patients with mTBI who are waiting for outpatient specialized rehabilitation services.

The effect of birth order on length of hospitalization for pediatric traumatic brain injury: an analysis of the 1987 Finnish birth cohort

Purpose

This study examines the relationship between birth order and length of hospitalization due to pediatric traumatic brain injury (TBI).

Methods

We prospectively followed 59,469 Finnish newborns from 1987 until age 18 years. Data on first diagnosis of TBI was recorded within the 1987 Finnish Birth Cohort (FBC). Hospitalization period was divided into two categories: 2 days or less and more than 2 days. The latter was considered in this study as longer hospitalization.

Results

Compared with first born siblings, later born siblings had an increased risk of a longer hospitalization for TBI (12.7% of fourth or higher born birth children diagnosed with TBI were hospitalized for 2 or more days, 11.3% of first born, 10.4% of third born and 9.0% of second born). Fourth or higher born children were more likely to experience a repeat TBI; 13.4% of fourth or higher born children diagnosed with TBI had 2–3 TBIs during the study period compared to 9% of third born, 7.8% of second born and 8.8% of the first born. Injuries in the traffic environment and falls were the most common contributors to pediatric TBI and occurred most frequently in the fourth or higher birth category; 29.3% of TBIs among fourth or higher birth order were due to transport accidents and 21% were due to falls.

Conclusions

This study revealed a significant increase in risk for longer hospitalization due to TBI among later born children within the same sibling group. The study provides epidemiological evidence on birth order as it relates to TBI, and its potential to help to explain some of the statistical variability in pediatric TBI hospitalization over time in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-022-00919-x.

Neurodevelopmental Outcomes in Preterm Children with Sickle Cell Disease

OBJECTIVES

To explore the combined effect of pediatric sickle cell disease (SCD) and preterm birth on cognitive functioning.

METHODS

Cognitive functioning was examined in children ages 6-8 with high risk SCD genotypes born preterm (n = 20) and full-term (n = 59) and lower risk SCD genotypes/no SCD born preterm (n = 11) and full-term (n = 99) using tests previously shown to be sensitive to SCD-related neurocognitive deficits. Factorial ANOVAs and log linear analyses were conducted to examine the relationship between SCD risk, preterm birth status, and cognitive outcomes. Continuous scores were examined for specific tests. Children were categorized as having an abnormal screening outcome if at least one cognitive score was ≥1.5 standard deviations below the population mean.

RESULTS

Children with elevated risk due to high risk SCD and preterm birth performed worse than other groups on a test of expressive language but not on tests that emphasize processing speed and working memory. There was a three-way interaction between preterm status, SCD risk, and abnormal screening outcome, which was largely driven by the increased likelihood of abnormal cognitive scores for children with high risk SCD born preterm.

CONCLUSIONS

The combination of SCD and preterm birth may confer increased risk for language deficits and elevated rates of abnormal cognitive screenings. This suggests that neurodevelopmental risk imparted by comorbid SCD and preterm birth may manifest as heterogenous, rather than specific, patterns of cognitive deficits. Future studies are needed to clarify the domains of cognitive functioning most susceptible to disease-related effects of comorbid SCD and preterm birth.

The influence of self-reported history of mild traumatic brain injury on cognitive performance

The long-term cognitive consequences of mild traumatic brain injury (mTBI) are poorly understood. Studies investigating cognitive performance in the chronic stage of injury in both hospital-based and population-based samples have revealed inconsistent findings. Importantly, population-based mTBI samples remain under-studied in the literature. This study investigated cognitive performance among individuals with a history of self-reported mTBI using a battery of cognitively demanding behavioural tasks. Importantly, more than half of the mTBI participants had experienced multiple mild head injuries. Compared to control participants (n = 49), participants with a history of mTBI (n = 30) did not demonstrate deficits in working memory, multitasking ability, cognitive flexibility, visuospatial ability, response inhibition, information processing speed or social cognition. There was moderate evidence that the mTBI group performed better than control participants on the visual working memory measure. Overall, these findings suggest that even multiple instances of mTBI do not necessarily lead to long-term cognitive impairment at the group level. Thus, we provide important evidence of the impact of chronic mTBI across a number of cognitive processes in a population-based sample. Further studies are necessary to determine the impact that individual differences in injury-related variables have on cognitive performance in the chronic stage of injury.

Is sentence ambiguity comprehension affected after mild traumatic brain injury? Results suggest cognitive control is more important than diagnosis

BACKGROUND

Individuals with mild traumatic brain injury (mTBI) may experience chronic cognitive-linguistic impairments that are difficult to evaluate with existing measures. Garden path sentences are linguistically complex sentences that lead readers down a path to an incorrect interpretation. Previous research indicates many individuals, with or without mTBI, may have difficulty fully resolving the ambiguity of garden path sentences, a skill which may require cognitive control. Evidence suggests cognitive control can be impacted by mTBI. Thus, impairments in cognitive control are expected to correlate with interpreting ambiguous sentences.

AIMS

To examine the relationship between cognitive control and the processing of ambiguous garden path sentences in adults with mTBI. We predict individuals with mTBI will perform more poorly on ambiguous sentence tasks compared with a control group. Further, we predict that performance on this task will correlate with measures of cognitive control and working memory.

METHODS & PROCEDURES

A total of 20 adults with mTBI history and 44 adults with no significant neurological history were recruited from the community. Participants completed a computerized, ambiguous sentence measure with carefully designed comprehension questions and an abbreviated neuropsychological battery of cognitive-linguistic tasks.

OUTCOMES & RESULTS

Participants performed similarly on sentence ambiguity resolution measures across groups with a wide range in performance. A comprehension measure aimed at identifying full ambiguity resolution correlated with cognitive control across groups.

CONCLUSIONS & IMPLICATIONS

A link between cognitive control and linguistic ambiguity is confirmed in a comprehension measure by the current findings. mTBI history did not appear to change the nature of the relationship between cognitive control and ambiguity resolution. High individual variability on sentence and cognitive control measures across groups suggest that if an impairment were present, it would affect both types of tasks. Thus, testing cognitive communication following mTBI should specifically examine complex cognitive and linguistic processing.

WHAT THIS PAPER ADDS

What is already known on the subject Cognitive control and ambiguous sentence processing are known to be linked, but the circumstances and individual variability associated with when cognitive control is recruited to support sentence processing are not fully understood. Very little is known about sentence processing following TBI history, despite cognitive control commonly being impaired following mild TBI. Thus, our study was necessary to explore the theoretical and clinical relationships between cognitive control and ambiguous sentence processing in individuals with mild TBI history. What this paper adds to existing knowledge This study adds to our understanding of how cognitive control and ambiguous sentence processing are linked in those with mild TBI history, and similar to the few previous studies, there were no group differences in cognitive or sentence measures. The positive correlation between cognitive control on Stroop and a particular ambiguous sentence comprehension question targeting inhibitory control highlights that any relationship between abilities or assessment tasks must be very specific to tasks with overlapping requirements, such as inhibition. What are the potential or actual clinical implications of this work? The relationship between cognitive and ambiguous sentence measures highlights the need to assess all areas of cognition and communication in those with mild TBI history without assuming that impairments in cognitive performance will relate to communication. The overlap between abilities is highly specific and must be explored on a case-by-case basis in those with mild TBI. Evaluation and treatment should still be individualized based on the functional communication profile of the client.

Associations between Intra-Individual Neurocognitive Variability and Prospective Memory in Veterans with Mild Traumatic Brain Injury History and Posttraumatic Stress Disorder

OBJECTIVE

Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) frequently co-occur and are associated with neurocognitive intra-individual variability (IIV) and difficulty with prospective memory (PM). The current study aimed to examine associations between IIV and PM in this comorbid group.

METHOD

Fifty veterans with a history of blast mTBI and current comorbid PTSD completed a standardized neurocognitive battery to measure IIV, and the Memory for Intentions Screening Test measuring PM.

RESULTS

Adjusting for age, education, and race, higher IIV was associated with poorer time-based PM (p < .001, f2 = .34), but not event-based PM. In a subset of the sample with self-report data, higher IIV was associated with poorer self-reported retrospective memory, but not PM.

CONCLUSIONS

Cognitive variability on a standardized neuropsychological battery was associated with strategically demanding PM, which is an ecologically relevant ability and highlights the possible connection between subtle cognitive difficulties in-clinic and those experienced in daily life.

Depression and Anxiety in Patients With a History of Traumatic Brain Injury: A Case-Control Study

Background

The burden of psychiatric illness following a head injury may have implications on the disease prognosis. The present study evaluated the association of depression and anxiety with traumatic brain injury (TBI).

Methods

A case-control study was conducted in Karachi, Pakistan, from 2nd July 2021 and 30th January 2022, including individuals of age 18 and above of both genders, with or without a mild head trauma history, forming the case and control groups, respectively. Individuals with previous head trauma/congenital neurological dysfunction were excluded. A mental health assessment of the participants was carried out with two scales, the Generalized Anxiety Disorder-7 (GAD-7) scale and the Public Health Questionnaire-9 (PHQ-9) scale. Other parameters like age, gender, socioeconomic status, education status, and comorbidities were also documented.

Results

A total of 62 participants were enrolled with 31 cases and 31 controls. The majority were males aged between 18 and 39 years. About 29% of the patients with a history of mild TBI had moderate to severe depression while only 22.6% of them did not have depression or had minimal depression. We found that about 29.3% of patients with TBI had severe anxiety as compared to the only two healthy controls. The majority of the control group participants did not have anxiety.

Conclusion

Traumatic head injuries and their long-term side effects can predispose patients to a myriad of psychiatric comorbidities. In this study, we found definitive evidence that both anxiety and depression had a significantly higher incidence in cohorts that suffered from mild TBI. However, we recommend large-scale and multicenter studies in the future to explore these relationships more thoroughly and comprehensively.

The 100 Most-Cited and Influential Articles in Collegiate Athletics

Background

Bibliometric citation analyses have been widely used in medicine to help researchers gain foundational knowledge about a topic and identify subtopics of popular interest for further investigations. There is a lack of similar research in collegiate athletics.

Purpose

To identify the 100 most-cited research publications related to collegiate athletics.

Study Design

Cross-sectional study.

Methods

The Clarivate Analytics Web of Knowledge database was used to generate a list of articles relating to collegiate athletics on January 24, 2022. Articles were filtered by the total number of citations, and the 100 most-cited articles were selected. For each article, we identified and analyzed the following: author name, publication year, country of origin, journal name, article type, main research topic area, competitive level, sex of study population, and level of evidence.

Results

Of the top 100 most-cited articles, 63 were related to medicine. In total, 96% of articles were published in the United States, and 80% were published in the year 2000 or later. Of the top 100 articles, 85 were observational; only 5 were experimental. The sport most represented was soccer, followed by football, baseball, and basketball. Of the top 100 articles, 21 were published in a single journal, the American Journal of Sports Medicine. Ten authors published ≥5 of the top 100 most-cited studies.

Conclusion

The majority of top 100 articles were published in the United States after 1999 and primarily focused on medicine-related topics. Soccer was studied by more articles than football, baseball, and basketball. An author's prestige may have influenced the likelihood of citation. The top 100 most-cited studies provide researchers, medical students, residents, and fellows with a foundational list of the most important and influential academic contributions to the literature on collegiate athletics.

Plasma Lipid Profiles Change with Increasing Numbers of Mild Traumatic Brain Injuries in Rats

Mild traumatic brain injury (mTBI) causes structural, cellular and biochemical alterations which are difficult to detect in the brain and may persist chronically following single or repeated injury. Lipids are abundant in the brain and readily cross the blood-brain barrier, suggesting that lipidomic analysis of blood samples may provide valuable insight into the neuropathological state. This study used liquid chromatography-mass spectrometry (LC-MS) to examine plasma lipid concentrations at 11 days following sham (no injury), one (1×) or two (2×) mTBI in rats. Eighteen lipid species were identified that distinguished between sham, 1× and 2× mTBI. Three distinct patterns were found: (1) lipids that were altered significantly in concentration after either 1× or 2× F mTBI: cholesterol ester CE (14:0) (increased), phosphoserine PS (14:0/18:2) and hexosylceramide HCER (d18:0/26:0) (decreased), phosphoinositol PI(16:0/18:2) (increased with 1×, decreased with 2× mTBI); (2) lipids that were altered in response to 1× mTBI only: free fatty acid FFA (18:3 and 20:3) (increased); (3) lipids that were altered in response to 2× mTBI only: HCER (22:0), phosphoethanolamine PE (P-18:1/20:4 and P-18:0/20:1) (increased), lysophosphatidylethanolamine LPE (20:1), phosphocholine PC (20:0/22:4), PI (18:1/18:2 and 20:0/18:2) (decreased). These findings suggest that increasing numbers of mTBI induce a range of changes dependent upon the lipid species, which likely reflect a balance of damage and reparative responses.

Hypertension and advanced age increase the risk of cognitive impairment after mild traumatic brain injury: A registry-based study

OBJECTIVE

As the global population ages, the incidence of traumatic brain injury (TBI) increases. While mild TBI can impair the cognitive function of older adults, the cause and background of mild TBI-induced cognitive impairment remains unclear, and the evaluation of risk factors for cognitive impairment after mild TBI remain open for consideration especially in the current aging society. This study aimed to evaluate the risks associated with cognitive impairment following mild TBI.

METHODS

Between January 2006 and December 2018, 2,209 patients with TBI required hospitalization in Shimane Prefectural Central Hospital. Mild TBI was defined as a Japan coma scale ≤ 10 at admission. The cognitive function of the patients was measured with the Hasegawa Dementia Rating Scale-revised or Mini-mental state examination at least twice during the patients' hospital stays. The odds ratio (OR) and 95% confidence interval (CI) of each considered risk factor was calculated with multivariable logistic regression analysis after univariate analysis.

RESULTS

Among 1,674 patients with mild TBI, 172 patients underwent cognitive function examinations, and 145 patients (84.3%) were found to have cognitive impairment at discharge. Significant risk factors for cognitive impairment included age (P = 0.008) and hypertension (P = 0.013) in univariate analysis; and age (OR 1.04: 95% CI 1.01-1.07) and hypertension (OR 5.81: 95% CI 1.22-27.68) by multivariable analysis.

CONCLUSIONS

Older patients with hypertension displayed significantly higher cognitive impairment risk after even mild TBI. For these patients, we should take carefully management even after mild TBI.

Repeated mild traumatic brain injury impairs fracture healing in male mice

Objectives

The goal of this study was to evaluate the long-term impact of repeated (r) mild traumatic brain injury (mTBI) on the healing of fractures in a mouse model. Ten week-old male mice were subjected to r-mTBI once per day for 4 days followed by closed femoral fracture using a three-point bending technique, 1 week post impact and fracture healing phenotype evaluated at 20 weeks of age.

Results

Micro-CT analysis of the fracture callus region at nine weeks post fracture revealed reduced bone volume (30%, p < 0.05) in the r-mTBI fracture group compared to the control-fracture group. The connectivity density of the fracture callus bone was reduced by 40% (p < 0.01) in the r-mTBI fracture group. Finite element analysis of the fracture callus region showed reduced failure load (p = 0.08) in the r-mTBI group compared to control group. There was no residual cartilage in the fracture callus region of either the r-mTBI or control fracture group. The reduced fracture callus bone volume and mechanical strength of fracture callus in r-mTBI mice 9 weeks post fracture are consistent with negative effects of r-mTBI on fracture healing over a long-term resulting in decreased mechanical strength of the fracture callus.

Preseason Symptom Reporting and Cognition in Middle School Athletes with Past Concussions

This study examined the association between past concussions and current preseason symptom reporting and cognitive performance in 9,257 youth ages 11-13. Participants completed neurocognitive testing prior to participating in a school sports between 2009 and 2019. We stratified the sample by gender and number of prior concussions and assessed group differences on the Post-Concussion Symptom Scale total score and the ImPACT cognitive composite scores. Those with≥2 prior concussions reported more symptoms than those with 0 concussions (d=0.43-0.46). Multiple regressions examining the contribution of concussion history and developmental/health history to symptom reporting showed the most significant predictors of symptoms scores were (in descending order): treatment for a psychiatric condition, treatment for headaches, history of learning disability (in boys only), history of attention-deficit/hyperactivity disorder, and age. Concussion history was the weakest statistically significant predictor in boys and not significant in girls. Cognitively, boys with 1 prior concussion had worse speed those with 0 concussions (d=0.11), and girls with≥2 prior concussions had worse verbal/visual memory than girls with 0 concussions (ds=0.38-0.39). In summary, youth with≥2 prior concussions reported more symptoms than those with no concussions. Boys with multiple concussions performed similarly on cognitive testing, while girls had worse memory scores.

Neurobehavioral Symptoms in U.S. Special Operations Forces in Rehabilitation After Traumatic Brain Injury: A TBI Model Systems Study

INTRODUCTION

Special Operations Forces (SOF) personnel are at increased risk for traumatic brain injury (TBI), when compared with conventional forces (CF). Prior studies of TBI in military samples have not typically investigated SOF vs. CF as specific subgroups, despite documented differences in premorbid resilience and post-injury comorbidity burden. The aim of the current study was to compare SOF vs. CF on the presence of neurobehavioral symptoms after TBI, as well as factors influencing perception of symptom intensity.

MATERIALS AND METHODS

This study conducted an analysis of the prospective veterans affairs (VA) TBI Model Systems Cohort, which includes service members and veterans (SM/V) who received inpatient rehabilitation for TBI at one of the five VA Polytrauma Rehabilitation Centers. Of those with known SOF status (N = 342), 129 participants identified as SOF (average age = 43 years, 98% male) and 213 identified as CF (average age = 38.7 years, 91% male). SOF vs. CF were compared on demographics, injury characteristics, and psychological and behavioral health symptoms. These variables were then used to predict neurobehavioral symptom severity in univariable and multivariable analyses.

RESULTS

SOF personnel reported significantly greater posttraumatic stress disorder (PTSD) symptoms but less alcohol and drug use than the CF. SOF also reported greater neurobehavioral symptoms. When examining those with TBIs of all severities, SOF status was not associated with neurobehavioral symptom severity, while race, mechanism of TBI, and PTSD symptoms were. When examining only those with mTBI, SOF status was associated with lower neurobehavioral symptoms, while PTSD severity, white race, and certain mechanisms of injury were associated with greater neurobehavioral symptoms.

CONCLUSIONS

Among those receiving inpatient treatment for TBI, SOF SM/V reported higher neurobehavioral and symptom severity. PTSD was the strongest predictor of neurobehavioral symptoms and should be considered an important treatment target in both SOF and CF with co-morbid PTSD/TBI. A proactive human performance approach towards identification and treatment of psychological and neurobehavioral symptoms is recommended for SOF.

Altered gray matter structural covariance networks at both acute and chronic stages of mild traumatic brain injury

Cognitive and emotional impairments observed in mild traumatic brain injury (mTBI) patients may reflect variances of brain connectivity within specific networks. Although previous studies found altered functional connectivity (FC) in mTBI patients, the alterations of brain structural properties remain unclear. In the present study, we analyzed structural covariance (SC) for the acute stages of mTBI (amTBI) patients, the chronic stages of mTBI (cmTBI) patients, and healthy controls. We first extracted the mean gray matter volume (GMV) of seed regions that are located in the default-mode network (DMN), executive control network (ECN), salience network (SN), sensorimotor network (SMN), and the visual network (VN). Then we determined and compared the SC for each seed region among the amTBI, the cmTBI and the healthy controls. Compared with healthy controls, the amTBI patients showed lower SC for the ECN, and the cmTBI patients showed higher SC for the both DMN and SN but lower SC for the SMN. The results revealed disrupted ECN in the amTBI patients and disrupted DMN, SN and SMN in the cmTBI patients. These alterations suggest that early disruptions in SC between bilateral insula and the bilateral prefrontal cortices may appear in amTBI and persist into cmTBI, which might be potentially related to the cognitive and emotional impairments.

Link between Mild Traumatic Brain Injury, Poor Sleep, and Magnetic Resonance Imaging: Visible Perivascular Spaces in Veterans

Impaired clearance of perivascular waste in the brain may play a critical role in morbidity after mild traumatic brain injury (mTBI). We aimed to determine the effect of mTBI on the burden of magnetic resonance imaging (MRI)-visible perivascular spaces (PVSs) in a cohort of U.S. military veterans and whether sleep modulates this effect. We also investigated the correlation between PVS burden and severity of persistent post-concussive symptoms. Fifty-six Iraq/Afghanistan veterans received 3 Tesla MRI as part of a prospective cohort study on military blast mTBI. White matter PVS burden (i.e., number and volume) was calculated using an established automated segmentation algorithm. Multi-variate regression was used to establish the association between mTBIs sustained in the military and PVS burden. Covariates included age, blood pressure, number of impact mTBIs outside the military, and blast exposures. Correlation coefficients were calculated between PVS burden and severity of persistent post-concussive symptoms. There was a significant positive relationship between the number of mTBIs sustained in the military and both PVS number and volume (p = 0.04). A significant interaction was found between mTBI and poor sleep on PVS volume (p = 0.04). A correlation was found between PVS number and volume, as well as severity of postconcussive symptoms (p = 0.03). Further analysis revealed a moderate correlation between PVS number and volume, as well as balance problems (p < 0.001). In Iraq/Afghanistan veterans, mTBI is associated with an increase in PVS burden. Further, an interaction exists between mTBI and poor sleep on PVS burden. Increased PVS burden, which may indicate waste clearance dysfunction, is associated with persistent post-concussive symptom severity.

Long-term effects of concussion on relevancy-based modulation of somatosensory-evoked potentials

OBJECTIVE

The purpose of this investigation was to better understand the effects of concussions on the ability to selectively up or down-regulate incoming somatosensory information based on relevance.

METHODS

Median nerve somatosensory-evoked potentials (SEPs) were elicited from electrical stimulation and recorded from scalp electrodes while participants completed tasks that altered the relevance of specific somatosensory information being conveyed along the stimulated nerve.

RESULTS

Within the control group, SEP amplitudes for task-relevant somatosensory information were significantly greater than for non-relevant somatosensory information at the earliest cortical processing potentials (N20-P27). Alternatively, the concussion history group showed similar SEP amplitudes for all conditions at early processing potentials, however a pattern similar to controls emerged later in the processing stream (P100) where both movement-related gating and facilitation of task-relevant information were present.

CONCLUSIONS

Previously concussed participants demonstrated impairments in the ability to up-regulate relevant somatosensory information at early processing stages. These effects appear to be chronic, as this pattern was observed on average several years after participants' most recent concussion.

SIGNIFICANCE

Given the role of the prefrontal cortex in relevancy-based facilitation during movement-related gating, these findings lend support to the notion that this brain area may be particularly vulnerable to concussive forces.

Blood-Brain Barrier Breakdown and Astrocyte Reactivity Evident in the Absence of Behavioral Changes after Repeated Traumatic Brain Injury

Repeated traumatic brain injuries (TBIs) cause debilitating effects. Without understanding the acute effects of repeated TBIs, treatment options to halt further degeneration and damage cannot be developed. This study sought to examine the acute effects of blood-brain barrier (BBB) dysfunction, edema, inflammation and behavioral changes after either a single or double TBI using a C57BL/6 mouse model. We examined the effects of one or two TBIs, of either a mild or moderate severity. Double injuries were spaced 7 days apart, and all analysis was performed 24 h post-injury. To examine edema and inflammation, protein levels of glial fibrillary acidic protein (GFAP), S100 calcium-binding protein B, interleukin-6, and matrix metallopeptidase 9 (MMP9) were analyzed. Aquaporin-4 (AQP4) and zonula occludens-1 (ZO-1) were analyzed to observe BBB dysfunction. Ionized calcium-binding adapter molecule 1 (IBA1) was analyzed to observe microglial activation. Rotarod, beam walking, and grip strength tests were used to measure changes in physical behavior post-injury. A sample size of ≥5 was used for all analysis. Double injuries led to an increase in BBB breakdown, as indicated by altered MMP-9, AQP4, and ZO-1 protein expression. Single injuries showed an increase in microglial activation, astrocyte activation, and BBB breakdown. Behavioral tasks showed no significant differences between injured and control groups. Based on our findings, we suggest that behavioral studies should not be used as the sole clinical indicator on brain tissue recovery. Analysis of markers such as IBA1, GFAP, MMP-9, AQP4, and ZO-1 provide valuable insight on pathophysiological response to injury.

Examining Conners Continuous Performance Test-3 (CPT-3) Embedded Performance Validity Indicators in an Adult Clinical Sample Referred for ADHD Evaluation

This study evaluated multiple previously-identified Continuous Performance Test-Third Edition (CPT-3) scores as embedded validity indicators (EVIs) among 201 adults undergoing neuropsychological evaluation for Attention-Deficit/Hyperactivity Disorder (ADHD) divided into valid (n = 169) and invalid (n = 32) groups based on seven criterion measures. Although 6/10 CPT-3 scores accurately detected invalidity, only two reached minimally acceptable classification accuracy of ≥0.70. The remaining four had unacceptably low accuracy (AUCs = 0.62-0.69) with 0.19-0.41 sensitivity at ≥0.90 specificity. Composite scores did not provide better classification accuracy than individual CPT-3 scores. In sum, CPT-3 individual and composite scores generally are not accurate PVTs among adults undergoing clinical evaluation for ADHD.

Post-exercise cognitive testing to assess persisting alterations in athletes with a history of concussion

Primary Objective: To determine whether a physical exercise protocol could reveal persistent cognitive alterations in university athletes with a history of concussion (HOC). Thirty-four HOC and 34 controls participated in this study.Research Design: Cross-sectional.Methods and Procedures: The exercise protocol consisted of a 20-min bout on a stationary bike at 80% of the theoretical maximal heart rate. Before and after the exercise, participants performed a computerized switch task designed specifically to recruit executive functions. Group × Condition (pre- and post-exercise) repeated measures of ANCOVAs for accuracy, reaction time, and inverse efficiency score on the switch task were conducted. Chi-square tests were run to determine if the proportion of HOC and controls who underperformed (at least 2SD lower than the control group's average score) at rest and post-exercise were similar. Whilst no interaction or main effects were found with ANCOVAs, significantly more HOC athletes (21%) underperformed following exercise than at rest (3%) on the switch task, p = .02. The current results indicate that an acute bout of exercise can reveal persistent alterations that are not present at rest in the protracted phase of concussion. They also highlight the importance of considering inter-individual differences in recovery trajectories.

Long-Term Effects of Repetitive Mild Traumatic Injury on the Visual System in Wild-Type and TDP-43 Transgenic Mice

Little is known about the impairments and pathological changes in the visual system in mild brain trauma, especially repetitive mild traumatic brain injury (mTBI). The goal of this study was to examine and compare the effects of repeated head impacts on the neurodegeneration, axonal integrity, and glial activity in the optic tract (OT), as well as on neuronal preservation, glial responses, and synaptic organization in the lateral geniculate nucleus (LGN) and superior colliculus (SC), in wild-type mice and transgenic animals with overexpression of human TDP-43 mutant protein (TDP-43^G348C) at 6 months after repeated closed head traumas. Animals were also assessed in the Barnes maze (BM) task. Neurodegeneration, axonal injury, and gliosis were detected in the OT of the injured animals of both genotypes. In the traumatized mice, myelination of surviving axons was mostly preserved, and the expression of neurofilament light chain was unaffected. Repetitive mTBI did not induce changes in the LGN and the SC, nor did it affect the performance of the BM task in the traumatized wild-type and TDP-43 transgenic mice. Differences in neuropathological and behavioral assessments between the injured wild-type and TDP-43^G348C mice were not revealed. Results of the current study suggest that repetitive mTBI was associated with chronic damage and inflammation in the OT in wild-type and TDP-43^G348C mice, which were not accompanied with behavioral problems and were not affected by the TDP-43 genotype, while the LGN and the SC remained preserved in the used experimental conditions.

Associations Among Increases in Posttraumatic Stress Symptoms, Neurocognitive Performance, and Long-Term Functional Outcomes in U.S. Iraq War Veterans

Cross-sectional research suggests that posttraumatic stress symptoms (PTSS) among war zone veterans are associated with functional impairment and poor quality of life. Less is known about the long-term functional repercussions of PTSS. This study of Iraq War veterans examined the associations between increases in PTSS and long-term functional outcomes, including the potential contributions of neurocognitive decrements. Service members and veterans (N = 594) completed self-report measures of functioning and PTSS severity before Iraq War deployment and again after their return (M = 9.3 years postdeployment). Some participants (n = 278) also completed neurocognitive testing at both times. Multiple regression analyses with the full sample-adjusted for TBI, demographic characteristics, military variables, and predeployment PTSS and functioning-revealed that increased PTSS severity over time was significantly associated with unemployment, aOR = 1.04, 95% CI [1.03, 1.06]; poorer work performance; and poorer physical, emotional, and cognitive health-related functioning at long-term follow-up, f² s = 0.37-1.79. Among participants who completed neurocognitive testing, a decline in select neurocognitive measures was associated with poorer functioning; however, neurocognitive decrements did not account for associations between increased PTSS and unemployment, aOR = 1.04, 95% CI [1.02, 1.07], with the size and direction upheld after adding neurocognitive variables, or poorer functional outcomes, with small increases after adding neurocognitive measures to the models, f² s = 0.03-0.10. War zone veterans experiencing long-term increased PTSS and/or neurocognitive decrements may be at elevated risk for higher-level functional impairment over time, suggesting that early PTSS management may enhance long-term functioning.

Simultaneous flow cytometric characterization of multiple cell types and metabolic states in the rat brain after repeated mild traumatic brain injury

BACKGROUND

Cellular responses at the sub-acute phase of mild traumatic brain injury (mTBI), and their contribution to ongoing damage, are unclear, complex and require simultaneous assessment of multiple cells to elucidate.

NEW METHOD

An 11-colour flow cytometry method for analysing brain cells was evaluated in a weight-drop rat model of repeated mTBI. Animals received sham, one, two or three mTBI delivered at 24 h intervals (n = 6/group). Cerebrum homogenates were prepared 11 days after first mTBI, in two cohorts of n = 3/group to enable same-day staining of fresh tissue. Percentages of neurons, astrocytes, microglia, mature oligodendrocytes and NeuN + CC1+ cells, neutrophils, macrophages and non-myeloid leukocytes, and their immunoreactivity for cell damage indicators (inducible nitric oxide synthase; iNOS, proliferating cell nuclear antigen; PCNA, 8-Oxo-2'-deoxyguanosine; 8OHDG and 4-hydroxynonenal; HNE), were assessed.

RESULTS

Median fluorescence intensity (MFI) of iNOS in activated microglia increased following two, but not one or three, mTBI (p = 0.04). However, there were differences between processing cohorts in terms of percentages and MFI of some PCNA+, iNOS+, 8OHDG + and HNE + cell populations.

COMPARISON WITH EXISTING METHODS

Previous applications of flow cytometry for rat brain analysis were typically limited to three or four markers. This method uses 11 markers to identify nine cell populations and evaluate their immunoreactivity to four metabolic indicators of cell damage.

CONCLUSIONS

Flow cytometry can be useful for discerning injury-related changes in multiple rat brain cells. However, markers sensitive to subtle changes in experimental conditions must be identified in pilot experiments and subsequently analysed in the same tissue-processing cohort.

Association of Previous Concussion with Hippocampal Volume and Symptoms in Collegiate-Aged Athletes

There is concern that previous concussion and contact-sport exposure may have negative effects on brain structure and function. Accurately quantifying previous concussion is complicated by the fact that multiple definitions exist, with recent definitions allowing for diagnosis based on the presence of symptoms alone (Concussion in Sport Group criteria; CISG) rather than the presence of acute injury characteristics such as alterations in mental status (American Congress of Rehabilitation Medicine criteria; ACRM). The goals of the current work were to determine the effects of previous concussion and contact-sport exposure on gray matter structure and clinical measures in healthy, young-adult athletes and determine the extent to which these associations are influenced by diagnostic criteria used to retrospectively quantify concussions. One-hundred eight collegiate-aged athletes were enrolled; 106 athletes were included in final analyses (age, 21.37 ± 1.69; 33 female). Participants completed a clinical battery of self-report and neurocognitive measures and magnetic resonance imaging to quantify subcortical volumes and cortical thickness. Semistructured interviews were conducted to measure exposure to contact sports and the number of previous concussions based on CISG and ACRM criteria. There was a significant association of concussion-related and psychological symptoms with previous concussions based on ACRM (ps < 0.05), but not CISG, criteria. Hippocampal volume was inversely associated with the number of previous concussions for both criteria (ps < 0.05). Findings provide evidence that previous concussions are associated with smaller hippocampal volumes and greater subjective clinical symptoms in otherwise healthy athletes and highlight the importance of diagnostic criteria used to quantify previous concussion.

A preliminary investigation of corpus callosum subregion white matter vulnerability and relation to chronic outcome in boxers

Microstructural neuropathology occurs in the corpus callosum (CC) after repetitive sports concussion in boxers and can be dose-dependent. However, the specificity and relation of CC changes to boxing exposure extent and post-career psychiatric and neuropsychological outcomes are largely unknown. Using deterministic diffusion tensor imaging (DTI) techniques, boxers and demographically-matched, noncontact sport athletes were compared to address literature gaps. Ten boxers and 9 comparison athletes between 26 and 59 years old (M = 44.63, SD = 9.24) completed neuropsychological testing and MRI. Quantitative DTI metrics were estimated for CC subregions. Group×Region interaction effects were observed on fractional anisotropy (FA; η²_p ≥ .21). Follow-up indicated large effects of group (η²_p ≥ .26) on splenium FA (boxers<comparisons) and genu mean diffusivity (MD; boxers>comparisons), but not radial diffusivity (RD). The group of boxers had moderately elevated number of psychiatric symptoms and reduced neuropsychological scores relative to the comparison group. In boxers, years sparring, professional bouts, and knockout history correlated strongly (r > |.40|) with DTI metrics and fine motor dexterity. In the comparison group, splenium FA correlated positively with psychiatric symptoms. In the boxer group, neuropsychological scores correlated with DTI metrics in all CC subregions. Results suggested relative vulnerability of the splenium and, to a lesser extent, the genu to chronic, repetitive head injury from boxing. Dose-dependent associations of professional boxing history extent with DTI white matter structure indices as well as fine motor dexterity were supported. Results indicated that symptoms of depression and executive dysfunction may provide the strongest indicators of global CC disruption from boxing.

A Genome-wide Association Study for Concussion Risk

PURPOSE

This study aimed to screen the entire genome for genetic markers associated with risk for concussion.

METHODS

A genome-wide association analyses was performed using data from the Kaiser Permanente Research Bank and the UK Biobank. Concussion cases were identified based on electronic health records from the Kaiser Permanente Research Bank and the UK Biobank from individuals of European ancestry. Genome-wide association analyses from both cohorts were tested for concussion using a logistic regression model adjusting for sex, height, weight, and race/ethnicity using allele counts for single nucleotide polymorphisms. Previously identified genes within the literature were also tested for association with concussion.

RESULTS

There were a total of 4064 cases of concussion and 291,472 controls within the databases, with two single nucleotide polymorphisms demonstrating a genome-wide significant association with concussion. The first polymorphism, rs144663795 (P = 9.7 × 10-11; OR = 2.91 per allele copy), is located within the intron of SPATA5. Strong, deleterious mutations in SPATA5 cause intellectual disability, hearing loss, and vision loss. The second polymorphism, rs117985931 (P = 3.97 × 10-9; OR = 3.59 per allele copy), is located within PLXNA4. PLXNA4 plays a key role is axon outgrowth during neural development, and DNA variants in PLXNA4 are associated with risk for Alzheimer's disease. Previous investigations have identified five candidate genes that may be associated with concussion, but none showed a significant association in the current model (P < 0.05).

CONCLUSION

Two genetic markers were identified as potential risk factors for concussion and deserve further validation and investigation of molecular mechanisms.

The power of appraisals in predicting PTSD symptom improvement following cognitive rehabilitation: A randomized clinical trial

BACKGROUND

Patients with PTSD often voice concern over their perceived change in cognitive functioning. However, these negative appraisals do not always align with objective neuropsychological performance, yet are strongly predictive of PTSD symptom severity and self-reported functional impairment.

METHODS

The present study involves a secondary analysis examining the role of appraisals of a subsample of 81 adults with full or subthreshold PTSD on treatment outcomes in a randomized controlled trial investigating the effectiveness of a cognitive rehabilitation treatment, Strategic Memory and Reasoning Training (n = 38), compared to a psychoeducation control arm, the Brain Health Workshop (n = 43). Neither condition addressed PTSD symptoms, focusing instead on cognitive skills training and psychoeducation about the brain.

RESULTS

Intent-to-treat models showed statistically significant improvements for both groups on composite scores of executive functioning and memory. Additionally, both groups experienced clinically significant reductions in PTSD symptoms (assessed via the Clinician-Administered PTSD Interview) and the SMART group showed fewer negative appraisals about cognitive functioning following training. Change in appraisals of cognitive functioning was associated with change in PTSD as well as change in quality of life, with no differential associations based on group status. In contrast, neurocognitive test score changes were not associated with change in symptoms or functional outcomes.

LIMITATIONS

We did not collect data on other appraisals (e.g., self-efficacy), which could have further elucidated pathways of change.

CONCLUSIONS

Our findings suggest that interventions that do not directly target PTSD symptoms can lead to PTSD symptom change via change in appraisals of functioning.

Epigenetic Blockade of Hippocampal SOD2 Via DNMT3b-Mediated DNA Methylation: Implications in Mild Traumatic Brain Injury-Induced Persistent Oxidative Damage

The recurrent events of mild trauma exacerbate the vulnerability for post-traumatic stress disorder; however, the underlying molecular mechanisms are scarcely known. The repeated mild traumatic brain injury (rMTBI) perturbs redox homeostasis which is primarily managed by superoxide dismutase 2 (SOD2). The current study investigates the role of DNA methylation in SOD2 gene regulation and its involvement in rMTBI-induced persistent neuropathology inflicted by weight drop injury paradigm. The oxidative damage, neurodegenerative indicators, and SOD2 function and its regulation in the hippocampus were analyzed after 48 h and 30 days of rMTBI. The temporal and episodic increase in ROS levels (oxidative stress) heightened 8-hydroxyguanosine levels indicating oxidative damage after rMTBI that was concomitant with decline in SOD2 function. In parallel, occupancy of DNMT3b at SOD2 promoter was higher post 30 days of the first episode of rMTBI causing hypermethylation at SOD2 promoter. This epigenetic silencing of SOD2 promoter was sustained after the second episode of rMTBI causing permanent blockade in SOD2 response. The resultant oxidative stress further culminated into the increasing number of degenerating neurons. The treatment with 5-azacytidine, a pan DNMT inhibitor, normalized DNA methylation levels and revived SOD2 function after the second episode of rMTBI. The release of blockade in SOD2 expression by DNMT inhibition also normalized the post-traumatic oxidative consequences and relieved the neurodegeneration and deficits in learning and memory as measured by novel object recognition test. In conclusion, DNMT3b-mediated DNA methylation plays a critical role in SOD2 gene regulation in the hippocampus, and the perturbations therein post rMTBI are detrimental to redox homeostasis manifesting into neurological consequences.

Use of Medical Cannabis to Treat Traumatic Brain Injury

There is not a single pharmacological agent with demonstrated therapeutic efficacy for traumatic brain injury (TBI). With recent legalization efforts and the growing popularity of medical cannabis, patients with TBI will inevitably consider medical cannabis as a treatment option. Pre-clinical TBI research suggests that cannabinoids have neuroprotective and psychotherapeutic properties. In contrast, recreational cannabis use has consistently shown to have detrimental effects. Our review identified a paucity of high-quality studies examining the beneficial and adverse effects of medical cannabis on TBI, with only a single phase III randomized control trial. However, observational studies demonstrate that TBI patients are using medical and recreational cannabis to treat their symptoms, highlighting inconsistencies between public policy, perception of potential efficacy, and the dearth of empirical evidence. We conclude that randomized controlled trials and prospective studies with appropriate control groups are necessary to fully understand the efficacy and potential adverse effects of medical cannabis for TBI.

Factors Associated with Symptom Reporting in U.S. Service Academy Cadets and NCAA Student Athletes without Concussion: Findings from the CARE Consortium

BACKGROUND

Symptom resolution is a key marker in determining fitness for return to activity following concussion, but in some cases, distinguishing persistent symptoms due to concussion versus symptoms related to other factors can be challenging.

OBJECTIVE

To determine base rates of postconcussional syndrome (PCS) diagnostic categorization in healthy cadets and student athletes with no recent concussion.

METHODS

13,009 cadets and 21,006 student athletes completed baseline preseason testing. After inclusion/exclusion criteria were applied, the final sample included 12,039 cadets [9123 men (75.8%); 2916 women (24.2%)] and 18,548 student athletes [10,192 men (54.9%); 8356 women (45.1%)]. Participants completed the Sport Concussion Assessment Tool-3rd Edition (SCAT3) symptom evaluation as part of baseline preseason testing. The PCS diagnostic categorization was classified by the International Classification of Diseases, 10th Revision (ICD-10) symptom criteria for PCS.

RESULTS

In the absence of recent concussion, subgroups of cadets (17.8% of men; 27.6% of women) and student athletes (11.4% of men; 20.0% of women) reported a cluster of symptoms that would meet the ICD-10 symptom criteria for PCS. Participants with insufficient sleep and/or preexisting conditions (e.g., mental health problems), freshmen cadets, and cadets at the U.S. Coast Guard Academy and at the U.S. Air Force Academy (freshmen were tested during basic cadet training) were more likely to report a cluster of symptoms that would meet the ICD-10 symptom criteria for PCS.

CONCLUSION

The ICD-10 symptom criteria for PCS can be mimicked by preexisting conditions, insufficient sleep, and/or stress. Findings support person-specific assessment and management of symptoms following concussion.

Neurocognitive effects of Moyamoya disease and concomitant epilepsy

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Results of neurocognitive evaluation in Moyamoya disease revealed a prominent executive burden.

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This dysexecutive pattern likely accounts for demonstrated difficulties with verbal memory.

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This case links a vascular dysexecutive pattern to verbal and visual memory in Moyamoya.

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The patient's seizures may contribute to his otherwise higher than expected affective symptoms.

Objective

Moyamoya disease (MMD) is a rare degenerative cerebrovascular disorder that leads to recurrent strokes and cerebral hypoperfusion. Seizures are not uncommon in MMD especially following surgical treatment for the disease. Cognitive changes that are largely executive in nature have been documented following MMD and surgical treatment, although research is limited in adults.

Methods

The present case report details the comprehensive neurocognitive evaluation of a patient with MMD and concomitant epilepsy.

Results

Neurocognitive findings revealed a prominent dysexecutive pattern and atypically poor performance in areas such as visual and verbal memory. The patient reported significant affective symptoms and functional decline.

Conclusions

This case offers insight into unique neurocognitive results that may present in adult MMD cases and underscores the importance of interpreting results in the context of neurological comorbidities in this rare disease.

Self-perceived irritability among OEF/OIF/OND veterans with a history of deployment-related mTBI: Associations with prospective memory and quality of life

OBJECTIVE

Examine relationships between self-perceived irritability, prospective memory, and quality of life (QOL) following mild traumatic brain injury (mTBI). Methods: 75 OEF/OIF/OND-era Veterans (56 deployment-related mTBI; 19 no history of TBI), were administered a battery of neuropsychological tests and self-report measures of mood and QOL. Self-perceived irritability was measured using the Neurobehavioral Symptom Inventory. Prospective memory (PM) was measured using the Memory for Intentions Test (MIST). Results: Self-perceived irritability was significantly higher for Veterans with, versus without, a history of deployment-related mTBI. Among Veterans with a history of mTBI, self-perceived irritability was inversely associated with PM performance, even after adjusting for PTSD severity. Greater self-perceived irritability was also associated with higher depressive symptoms and reduced QOL for perceived physical health, psychological health, social support, and environmental factors; however, only social support remained significant after adjusting for PTSD severity. Depression symptom severity was not significantly associated with PM, suggesting that PM may be uniquely related to self-perceived irritability rather than mood dysregulation more generally. Conclusions: Findings provide preliminary evidence of a relationship between PM and self-perceived irritability in Veterans with a history of mTBI. PM and irritability may be related via their mutual reliance on high-level cognitive control. Results illustrate possible cognitive and affective factors contributing to psychological and interpersonal challenges for this population. Future investigations with larger and more diverse samples are needed to replicate findings and explore potential mechanisms linking irritability and PM following mTBI.

Neurocognitive performance and mental health of retired female football players compared to non-contact sport athletes

Background

Adverse long-term effects of playing football due to repetitive head impact exposure on neurocognition and mental health are controversial. To date, no studies have evaluated such effects in women.

Aims

To (1) compare neurocognitive performance, cognitive symptoms and mental health in retired elite female football players (FB) with retired elite female non-contact sport athletes (CON), and to (2) assess whether findings are related to history of concussion and/or heading exposure in FB.

Methods

Neurocognitive performance, mental health and cognitive symptoms were assessed using computerised tests (CNS-vital signs), paper pen tests (Category fluency, Trail-Making Test, Digit Span, Paced Auditory Serial Addition Test), questionnaires (Hospital Anxiety and Depression Scale, SF-36v2 Health Survey) and a symptom checklist. Heading exposure and concussion history were self-reported in an online survey and in a clinical interview, respectively. Linear regression was used to analyse the effect of football, concussion and heading exposure on outcomes adjusted for confounders.

Results

FB (n=66) performed similar to CON (n=45) on neurocognitive tests, except for significantly lower scores on verbal memory (mean difference (MD)=−7.038, 95% CI −12.98 to –0.08, p=0.038) and verbal fluency tests (MD=−7.534, 95% CI –13.75 to –0.46, p=0.016). Among FB weaker verbal fluency performance was significantly associated with ≥2 concussions (MD=−10.36, 95% CI –18.48 to –2.83, p=0.017), and weaker verbal memory performance with frequent heading (MD=−9.166, 95% CI –17.59 to –0.123, p=0.041). The depression score differed significantly between study populations, and was significantly associated with frequent heading but not with history of concussion in FB.

Conclusion

Further studies should investigate the clinical relevance of our findings and whether the observed associations point to a causal link between repetitive head impacts and verbal memory/fluency or mental health.