Traumatic brain injury and chronic traumatic encephalopathy: a forensic neuropsychiatric perspective

Unusual combinations of neurodegenerative pathologies with chronic traumatic encephalopathy (CTE) complicates clinical prediction of CTE

BACKGROUND AND PURPOSE

Chronic traumatic encephalopathy (CTE) has gained widespread attention due to its association with multiple concussions and contact sports. However, CTE remains a postmortem diagnosis, and the link between clinical symptoms and CTE pathology is poorly understood. This study aimed to investigate the presence of copathologies and their impact on symptoms in former contact sports athletes.

METHODS

This was a retrospective case series design of 12 consecutive cases of former contact sports athletes referred for autopsy. Analyses are descriptive and include clinical history as well as the pathological findings of the autopsied brains.

RESULTS

All participants had a history of multiple concussions, and all but one had documented progressive cognitive, psychiatric, and/or motor symptoms. The results showed that 11 of the 12 participants had evidence of CTE in the brain, but also other copathologies, including different combinations of tauopathies, and other rare entities.

CONCLUSIONS

The heterogeneity of symptoms after repetitive head injuries and the diverse pathological combinations accompanying CTE complicate the prediction of CTE in clinical practice. It is prudent to consider the possibility of multiple copathologies when clinically assessing patients with repetitive head injuries, especially as they age, and attributing neurological or cognitive symptoms solely to presumptive CTE in elderly patients should be discouraged.

Functional Neurological Disorder Presenting After Concussion: A Retrospective Case Series

OBJECTIVE

Although a majority of individuals recover from a concussion within weeks of the index injury, a substantial minority of patients report persistent postconcussion symptoms. Some of these symptoms may reflect a diagnosis of functional neurological disorder (FND). The authors evaluated the relationship between persistent postconcussion symptoms and FND symptoms.

METHODS

In this retrospective chart review, the authors characterized demographic and clinical information from 50 patients with a confirmed diagnosis of FND whose functional neurological symptoms started after a concussion.

RESULTS

Patients who developed FND after a concussion had high rates of baseline risk factors for both persistent postconcussion symptoms and FND. After the concussive event, functional neurological symptoms presented abruptly or developed insidiously over time. Functional neurological symptoms ranged widely and included gait symptoms, seizures, speech and language symptoms, weakness, sensory symptoms, tremors, and vision and oculomotor symptoms.

CONCLUSIONS

Functional neurological symptoms can arise after a concussion. FND should be considered in the differential diagnosis of individuals presenting with neurological symptoms beginning after a concussion. By failing to recognize functional symptoms, clinicians may inadvertently reinforce negative health-related beliefs regarding a patient's injured brain.

Differential Vulnerability of Hippocampal Subfields in Primary Age-Related Tauopathy and Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a tauopathy associated with repetitive mild head impacts characterized by perivascular hyperphosphorylated tau (p-tau) in neurofibrillary tangles (NFTs) and neurites in the depths of the neocortical sulci. In moderate to advanced CTE, NFTs accumulate in the hippocampus, potentially overlapping neuroanatomically with primary age-related tauopathy (PART), an age-related tauopathy characterized by Alzheimer disease-like tau pathology in the hippocampus devoid of amyloid plaques. We measured p-tau burden using positive-pixel counts on immunohistochemically stained and neuroanatomically segmented hippocampal tissue. Subjects with CTE had a higher total p-tau burden than PART subjects in all sectors (p = 0.005). Within groups, PART had significantly higher total p-tau burden in CA1/subiculum compared to CA3 (p = 0.02) and CA4 (p = 0.01) and total p-tau burden in CA2 trended higher than CA4 (p = 0.06). In CTE, total p-tau burden in CA1/subiculum was significantly higher than in the dentate gyrus; and CA2 also trended higher than dentate gyrus (p = 0.01, p = 0.06). When controlling for p-tau burden across the entire hippocampus, CA3 and CA4 had significantly higher p-tau burden in CTE than PART (p < 0.0001). These data demonstrate differences in hippocampal p-tau burden and regional distribution in CTE compared to PART that might be helpful in differential diagnosis and reveal insights into disease pathogenesis.

The Biological Basis of Chronic Traumatic Encephalopathy following Blast Injury: A Literature Review

The United States Department of Defense Blast Injury Research Program Coordinating Office organized the 2015 International State-of-the-Science meeting to explore links between blast-related head injury and the development of chronic traumatic encephalopathy (CTE). Before the meeting, the planning committee examined articles published between 2005 and October 2015 and prepared this literature review, which summarized broadly CTE research and addressed questions about the pathophysiological basis of CTE and its relationship to blast- and nonblast-related head injury. It served to inform participants objectively and help focus meeting discussion on identifying knowledge gaps and priority research areas. CTE is described generally as a progressive neurodegenerative disorder affecting persons exposed to head injury. Affected individuals have been participants primarily in contact sports and military personnel, some of whom were exposed to blast. The symptomatology of CTE overlaps with Alzheimer's disease and includes neurological and cognitive deficits, psychiatric and behavioral problems, and dementia. There are no validated diagnostic criteria, and neuropathological evidence of CTE has come exclusively from autopsy examination of subjects with histories of exposure to head injury. The perivascular accumulation of hyperphosphorylated tau (p-tau) at the depths of cortical sulci is thought to be unique to CTE and has been proposed as a diagnostic requirement, although the contribution of p-tau and other reported pathologies to the development of clinical symptoms of CTE are unknown. The literature on CTE is limited and is focused predominantly on head injuries unrelated to blast exposure (e.g., football players and boxers). In addition, comparative analyses of clinical case reports has been challenging because of small case numbers, selection biases, methodological differences, and lack of matched controls, particularly for blast-exposed individuals. Consequently, the existing literature is not sufficient to determine whether the development of CTE is associated with head injury frequency (e.g., single vs. multiple exposures) or head injury type (e.g., impact, nonimpact, blast-related). Moreover, the incidence and prevalence of CTE in at-risk populations is unknown. Future research priorities should include identifying additional risk factors, pursuing population-based longitudinal studies, and developing the ability to detect and diagnose CTE in living persons using validated criteria.

Diagnosis makes a difference: Perceptions of older persons with dementia symptoms

Background/Study Context: Employing the stereotype content model and terror management theory, we examined whether stereotypes and feelings about persons with dementia vary depending on the type of dementia diagnosis and purported causes of the dementia.

METHODS

Participants were randomly assigned to read one of four vignettes that depicted a man who consulted his doctor because of memory problems. All vignettes described the same symptoms and diagnostic tests, but each of four groups read a different result: all tests normal (Normal); Alzheimer's disease (AD); Wernicke-Korsakoff Syndrome (WKS) associated with alcohol abuse; and chronic traumatic encephalopathy (CTE) associated with head injuries from playing football in high school and college. Measures included a word fragment completion task, a stereotype content scale, and an emotions scale.

RESULTS

Results showed no differences in the number of death-related words generated in the word fragment completion task and no differences in assessment of competence across the four groups. Those in the Normal, AD, and CTE groups evaluated the man as warmer than those in the WKS group. Participants in the AD condition showed more empathy than those in the WKS group. There were no differences in pity or fear but the CTE condition produced more envy and admiration and the WKS condition produced more contempt.

CONCLUSION

These results suggest that different forms of dementia elicit varying emotional and cognitive responses.

Psychiatric phenotypes in chronic traumatic encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder involving cognitive, motor, and psychiatrically-relevant symptoms resulting from repetitive head impacts. Psychiatric phenotypes of CTE, including depression and suicidality, present particular challenges for CTE research, given that the diagnosis requires postmortem neuropathological examination. The pathognomonic lesion of CTE is the perivascular accumulation of hyperphosphorylated tau (ptau) protein at the depths of cortical sulci. These lesions are found in the earliest disease stages, and with advancing pathological severity, ptau deposition occurs in widespread brain regions in a four-stage scheme of severity. We review the psychiatric phenotypes of individuals neuropathologically diagnosed with CTE, and suggest that earlier CTE stages hold particular interest for psychiatric CTE research. In the early CTE stages, there is ptau pathology in frontal cortex and axonal loss in the frontal white matter, followed by progressive ptau neurofibrillary degeneration in the amygdala and hippocampus. Neuropathological changes in the frontal and medial temporal lobes may underlie psychiatric phenotypes. Additional insight into the association between CTE pathology and psychiatric sequelae may come from advancements in in vivo methods of CTE detection. Further epidemiological, clinical, and postmortem studies are needed to validate the nature of psychiatric sequelae in CTE.

Veteran treatment courts: A promising solution

The high prevalence of substance use, traumatic brain injury, post-traumatic stress disorder, and other mental illness in the veteran population presents unique public health and social justice challenges. Veteran involvement in the justice system has been identified as a national concern. Criminal justice involvement compounds pre-existing socioeconomic stressors and further strains support systems. The point of contact with the criminal justice system, however, presents an opportunity to establish mental health treatment. This is consistent with the concept of the sequential intercept model that seeks to divert offenders with mental illness from the criminal justice system into treatment. In recent years, many jurisdictions have established veterans treatment courts (VTCs), a type of problem-solving court serving this diversion function for military veterans. This article presents an overview of the problem, the ethical basis for their development, a brief history of the courts, and their potential for success. The Harris County Veterans Court is presented as an example.

A systematic review of potential long-term effects of sport-related concussion

Objective

Systematic review of possible long-term effects of sports-related concussion in retired athletes.

Data sources

Ten electronic databases.

Study selection

Original research; incidence, risk factors or causation related to long-term mental health or neurological problems; individuals who have suffered a concussion; retired athletes as the subjects and possible long-term sequelae defined as >10 years after the injury.

Data extraction

Study population, exposure/outcome measures, clinical data, neurological examination findings, cognitive assessment, neuroimaging findings and neuropathology results. Risk of bias and level of evidence were evaluated by two authors.

Results

Following review of 3819 studies, 47 met inclusion criteria. Some former athletes have depression and cognitive deficits later in life, and there is an association between these deficits and multiple prior concussions. Former athletes are not at increased risk for death by suicide (two studies). Former high school American football players do not appear to be at increased risk for later life neurodegenerative diseases (two studies). Some retired professional American football players may be at increased risk for diminishment in cognitive functioning or mild cognitive impairment (several studies), and neurodegenerative diseases (one study). Neuroimaging studies show modest evidence of macrostructural, microstructural, functional and neurochemical changes in some athletes.

Conclusion

Multiple concussions appear to be a risk factor for cognitive impairment and mental health problems in some individuals. More research is needed to better understand the prevalence of chronic traumatic encephalopathy and other neurological conditions and diseases, and the extent to which they are related to concussions and/or repetitive neurotrauma sustained in sports.

Neuropsychiatric aspects of concussion: acute and chronic sequelae

Concussion – also known as mild traumatic brain injury – is a transient disturbance of neurological function resulting from traumatic forces imparted to the brain that often produce cognitive, behavioral and systemic symptoms. In this review of the literature, we discuss the pathophysiology of both acute and chronic neuropsychiatric sequelae of concussions, followed by a brief overview of evaluation and management of these sequelae.

Suicide Mortality Among Retired National Football League Players Who Played 5 or More Seasons

BACKGROUND

There is current disagreement in the scientific literature about the relationship between playing football and suicide risk, particularly among professional players in the National Football League (NFL). While some research indicates players are at high risk of football-related concussions, which may lead to chronic traumatic encephalopathy and suicide, other research finds such a connection to be speculative and unsupported by methodologically sound research.

PURPOSE

To compare the suicide mortality of a cohort of NFL players to what would be expected in the general population of the United States.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A cohort of 3439 NFL players with at least 5 credited playing seasons between 1959 and 1988 was assembled for statistical analysis. The vital status for this cohort was updated through 2013. Standardized mortality ratios (SMRs), the ratio of observed deaths to expected deaths, and 95% CIs were computed for the cohort; 95% CIs that excluded unity were considered statistically significant. For internal comparison purposes, standardized rate ratios were calculated to compare mortality results between players stratified into speed and nonspeed position types.

RESULTS

Suicide among this cohort of professional football players was significantly less than would be expected in comparison with the United States population (SMR = 0.47; 95% CI, 0.24-0.82). There were no significant differences in suicide mortality between speed and nonspeed position players.

CONCLUSION

There is no indication of elevated suicide risk in this cohort of professional football players with 5 or more credited seasons of play. Because of the unique nature of this cohort, these study results may not be applicable to professional football players who played fewer than 5 years or to college or high school players.

Retirement and Activity Restrictions Following Concussion

Sport-related concussion is prevalent at all levels of play. Increased attention from sports media and scientific and medical communities has prompted players and physicians to explore the long-term effects of concussion and ask the questions of when and how players should begin to mitigate their concussion risk. The authors evaluate their risks from the perspective of epidemiology, symptomatology, neuropsychological performance, and biomechanics. The authors propose that there is not a set number of concussions that necessitates retirement in athletes and, aside from a few absolute contraindications to return to collision sport, return to play should be an individualized process.

Elevated C-reactive protein levels may be a predictor of persistent unfavourable symptoms in patients with mild traumatic brain injury: a preliminary study

The pathogenesis of persistent unfavourable outcomes following mild traumatic brain injury (mTBI) are not fully understood. Low-grade systemic inflammation might contribute to the development of persistent unfavourable outcomes in patients with mTBI. We used plasma high-sensitivity C-reactive protein (CRP) levels as the biomarker of systemic inflammation to investigate whether elevated CRP levels were associated with persistent adverse outcomes in these patients. A total of 213 consecutive patients with mTBI were identified in our study. Plasma high-sensitivity CRP levels were measured at baseline, 1month, 2months and 3months after initial traumatic brain injury. The study endpoints included persistent postconcussion syndrome (PCS), persistent psychological problems (depression and anxiety), persistent physiological problems (frequent headache, nausea, insomnia, dizziness and fatigue) and persistent cognitive impairment, which were screened by International Classification of Diseases (ICD-10), diagnostic and statistical manual of mental disorders (DSM-IV), Beck anxiety inventory (BAI), Beck depression inventory (BDI) and montreal cognitive assessment (MoCA) 3months post-injury. The associations between baseline CRP levels and persistent unfavourable outcomes were estimated from multiple regression models adjusting for various confounding covariates. Elevated baseline CRP levels were associated with a significant increase in the incidence of persistent PCS (odds ratio [OR], 2.719; 95% confidence interval [CI], 1.609-4.594; p=0.000), persistent psychological problems (OR, 1.535; 95% CI, 1.063-2.216; p=0.022), and persistent cognitive impairment (OR, 1.687; 95% CI, 1.135-2.507; p=0.010). However, elevated CRP levels were not associated with persistent physiological problems (OR, 1.330; 95% CI, 0.905-1.956; p=0.146). Furthermore, three adjusted models did not essentially affect the OR of elevated CRP levels for these persistent unfavourable outcomes. Among patients with mTBI, baseline elevated CRP levels may be an independent predictor of persistent persistent PCS, psychological problems and cognitive impairment.

Chronic traumatic encephalopathy and other neurodegenerative proteinopathies

"Chronic traumatic encephalopathy" (CTE) is described as a slowly progressive neurodegenerative disease believed to result from multiple concussions. Traditionally, concussions were considered benign events and although most people recover fully, about 10% develop a post-concussive syndrome with persisting neurological, cognitive and neuropsychiatric symptoms. CTE was once thought to be unique to boxers, but it has now been observed in many different athletes having suffered multiple concussions as well as in military personal after repeated blast injuries. Much remains unknown about the development of CTE but its pathological substrate is usually tau, similar to that seen in Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD). The aim of this "perspective" is to compare and contrast clinical and pathological CTE with the other neurodegenerative proteinopathies and highlight that there is an urgent need for understanding the relationship between concussion and the development of CTE as it may provide a window into the development of a proteinopathy and thus new avenues for treatment.

Chronic traumatic encephalopathy and suicide: a systematic review

Traumatic brain injury (TBI) is a global health concern, and the recent literature reports that a single mild TBI can result in chronic traumatic encephalopathy (CTE). It has been suggested that CTE may lead to death by suicide, raising important prevention, treatment, and policy implications. Thus, we conducted a systematic review of the medical literature to answer the key question: What is the existing evidence in support of a relationship between CTE and suicide? Systematic searches of CTE and suicide yielded 85 unique abstracts. Seven articles were identified for full text review. Only two case series met inclusion criteria and included autopsies from 17 unique cases, 5 of whom died by suicide. Neither studies used blinding, control cases, or systematic data collection regarding TBI exposure and/or medical/neuropsychiatric history. The identified CTE literature revealed divergent opinions regarding neuropathological elements of CTE and heterogeneity regarding clinical manifestations. Overall quality of evidence regarding a relationship between CTE and suicide was rated as very low using Grading of Recommendations Assessment, Development and Evaluation Working Group (GRADE) criteria. Further studies of higher quality and methodological rigor are needed to determine the existence and nature of any relationship between CTE and suicide.