Sensory Sensitivity in TBI: Implications for Chronic Disability.

PURPOSE OF REVIEW: This review investigates the relationship between sensory sensitivity and traumatic brain injury (TBI), and the role sensory sensitivity plays in chronic disability. RECENT FINDINGS: TBI is a significant cause of disability with a range of physical, cognitive, and mental health consequences. Sensory sensitivities (e.g., noise and light) are among the most frequently reported, yet least outwardly recognizable symptoms following TBI. Clinicians and scientists alike have yet to identify consistent nomenclature for defining noise and light sensitivity, making it difficult to accurately and reliably assess their influence. Noise and light sensitivity can profoundly affect critical aspects of independent function including communication, productivity, socialization, cognition, sleep, and mental health. Research examining the prevalence of sensory sensitivity and evidence for the association of sensory sensitivity with TBI is inconclusive. Evidence-based interventions for sensory sensitivity, particularly following TBI, are lacking.

Pain and chronic mild traumatic brain injury in the US military population: a Chronic Effects of Neurotrauma Consortium study.

PRIMARY OBJECTIVES: To describe the association between mild traumatic brain injury (mTBI) and pain intensity and pain interference outcomes while accounting for potential confounders and mediators including environmental factors and comorbidities in a cohort of US Veterans of the Iraq and Afghanistan wars. RESEARCH DESIGN: Cross-sectional snapshot of baseline data from a prospective, longitudinal study. METHODS: Effects of mTBI on pain intensity and pain interference were compared between participants with or without mTBI exposure. Data were analysed using covariate-adjusted regression analyses as well as structural equation modelling (SEM) methods to assess the robustness of findings across different modelling assumptions. As results of the two approaches were consistent with respect to the overall association between mTBI exposure and pain, the results focus primarily on the SEM findings. RESULTS: The mTBI exposed group reported significantly greater indices of post-traumatic stress disorder (PTSD), depression, anxiety and sleep disturbance. After accounting for other factors, mTBI exposure was significantly, but indirectly associated with the pain interference and pain intensity outcomes. CONCLUSIONS: mTBI is strongly associated with pain intensity and pain interference in this sample. However, the effect appears to be mediated by other common mTBI comorbidities: PTSD, depression, anxiety and sleep disturbance.

Suicide and Chronic Traumatic Encephalopathy.

For nearly 80 years, suicidality was not considered to be a core clinical feature of chronic traumatic encephalopathy (CTE). In recent years, suicide has been widely cited as being associated with CTE, and now depression has been proposed to be one of three core diagnostic features alongside cognitive impairment and anger control problems. This evolution of the clinical features has been reinforced by thousands of media stories reporting a connection between mental health problems in former athletes and military veterans, repetitive neurotrauma, and CTE. At present, the science underlying the causal assumption between repetitive neurotrauma, depression, suicide, and the neuropathology believed to be unique to CTE is inconclusive. Epidemiological evidence indicates that former National Football League players, for example, are at lower, not greater, risk for suicide than men in the general population. This article aims to discuss the critical issues and literature relating to these possible relationships.

Beta-amyloid deposition in chronic traumatic encephalopathy.

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with repetitive mild traumatic brain injury. It is defined pathologically by the abnormal accumulation of tau in a unique pattern that is distinct from other tauopathies, including Alzheimer's disease (AD). Although trauma has been suggested to increase amyloid ß peptide (Aß) levels, the extent of Aß deposition in CTE has not been thoroughly characterized. We studied a heterogeneous cohort of deceased athletes and military veterans with neuropathologically diagnosed CTE (n = 114, mean age at death = 60) to test the hypothesis that Aß deposition is altered in CTE and associated with more severe pathology and worse clinical outcomes. We found that Aß deposition, either as diffuse or neuritic plaques, was present in 52 % of CTE subjects. Moreover, Aß deposition in CTE occurred at an accelerated rate and with altered dynamics in CTE compared to a normal aging population (OR = 3.8, p < 0.001). We also found a clear pathological and clinical dichotomy between those CTE cases with Aß plaques and those without. Aß deposition was significantly associated with the presence of the APOE ε4 allele (p = 0.035), older age at symptom onset (p < 0.001), and older age at death (p < 0.001). In addition, when controlling for age, neuritic plaques were significantly associated with increased CTE tauopathy stage (ß = 2.43, p = 0.018), co-morbid Lewy body disease (OR = 5.01, p = 0.009), and dementia (OR = 4.45, p = 0.012). A subset of subjects met the diagnostic criteria for both CTE and AD, and in these subjects both Aß plaques and total levels of Aß1-40 were increased at the depths of the cortical sulcus compared to the gyral crests. Overall, these findings suggest that Aß deposition is altered and accelerated in a cohort of CTE subjects compared to normal aging and that Aß is associated with both pathological and clinical progression of CTE independent of age.

Chronic traumatic encephalopathy in professional sports: retrospective and prospective views.

PRIMARY OBJECTIVE: The purposes of this paper are to review: (1) the history of chronic traumatic encephalopathy (CTE) in sports, (2) the similarities and differences between historic and current definitions of CTE, (3) recent epidemiology and cohort studies of CTE and (4) controversies regarding the current CTE positions. RESEARCH DESIGN: Not applicable. METHODS AND PROCEDURES: Selective review of published articles relevant to CTE. MAIN OUTCOME AND RESULTS: The current definitions of CTE have evolved from its original definition and now rely heavily on the post-mortem detection of hyperphosphorylated tau for diagnosis. As of 2013, there is a blended cohort of 110 professional athletes diagnosed with CTE. It is being assumed that concussions and/or sub-concussive impacts in contact sports are the sole cause of CTE. CONCLUSIONS: There are multiple causes of abnormal tau protein deposition in the human brain and the pathogenesis of CTE may not be related solely to concussion and/or sub-concussive injury. In all likelihood, the causes of CTE are a multivariate, as opposed to a univariate, phenomenon.

Talking with parents of high school football players about chronic traumatic encephalopathy: a concise summary.

Over the past decade, athletic-related chronic traumatic encephalopathy (CTE) has garnered a great deal of attention in the popular press and, more recently, in the scientific press. With increasing frequency, sports medicine practitioners and providers are faced with questions from the parents of high school football players about CTE and the risk posed to children who participate in this or other contact or collision sports. The purpose of this review was to summarize the research on CTE in an attempt to provide some evidence-based answers to frequently asked questions in clinics from parents. Addressed are (1) the definitions of CTE and its symptoms, (2) the evidence for CTE in football, (3) abnormal tau protein, (4) the use of neuroimaging in CTE diagnosis, (5) risk for CTE, (6) CTE diagnosis in youth, (7) CTE and its relationship to suicide, and (8) contact and collision sports as a risk factor for permanent brain injury or death.

Chronic traumatic encephalopathy and the availability cascade.

Chronic traumatic encephalopathy (CTE) in sports has been known for > 85 years, and has experienced a resurgence of interest over the past decade, both in the media and in the scientific community. However, there appears to be a disconnection between the public's perception of CTE and the currently available scientific data. The cognitive bias known as the "availability cascade" has been suggested as a reason to explain this rift in knowledge. This review summarizes and updates the history of CTE in sports, discusses recent epidemiological and autopsy studies, summarizes the evidence base related to CTE in sports, and offers recommendations for future directions.

Military traumatic brain injury: a review.

Military mild traumatic brain injury (mTBI) differs from civilian injury in important ways. Although mTBI sustained in both military and civilian settings are likely to be underreported, the combat theater presents additional obstacles to reporting and accessing care. The impact of blast forces on the nervous system may differ from nonblast mechanisms, mTBI although studies comparing the neurologic and cognitive sequelae in mTBI survivors have not provided such evidence. However, emotional distress appears to figure prominently in symptoms following military mTBI. This review evaluates the extant literature with an eye towards future research directions.

Modern chronic traumatic encephalopathy in retired athletes: what is the evidence?

It has been theorized that a career in contact sports may be associated with long-term neurodegenerative changes. This idea dates as far back as the 1920s, was initially reported in boxers, colloquially termed 'punch drunk,' later more formally termed dementia pugilistica (DP), and now coined chronic traumatic encephalopathy (CTE). Despite considerable ongoing interest on this topic, there is so far only limited evidence showing an association between sport-related concussion (SRC) and increased risk for late-life cognitive and neuropsychiatric impairment, with no causality or risk factors yet determined. The modern CTE description is nevertheless proposed as a unique tauopathy with characteristic pathological stages occurring in retired athletes who have experienced previous repetitive brain trauma. This review highlights the principal issues that so far preclude firm conclusions about the association of athletic head trauma and neurodegenerative diseases of any type. We consider alternative interpretations that may contribute to the clinical progressive neurological findings in some athletes and recommend carefully-controlled epidemiological work to overcome current limitations in this area of research and stimulate future research.

Chronic traumatic encephalopathy: where are we and where are we going?

Chronic traumatic encephalopathy (CTE, previously called punch drunk and dementia pugilistica) has a rich history in the medical literature in association with boxing, but has only recently been recognized with other contact sports, such as football and ice hockey, as well as with military blast injuries. CTE is thought to be a neurodegenerative disease associated with repeated concussive and subconcussive blows to the head. There is characteristic gross and microscopic pathology found in the brain, including frontal and temporal atrophy, axonal degeneration, and hyperphosphorylated tau and TAR DNA-binding protein 43 pathology. Clinically, there are characteristic progressive deficits in cognition (memory, executive dysfunction), behavior (explosivity, aggression), mood (depression, suicidality), and motor function (parkinsonism), which correlate with the anatomic distribution of brain pathology. While CTE shares clinical and neuropathological traits with other neurodegenerative diseases, the clinical syndrome and the neuropathology as a whole are distinct from other neurodegenerative diseases. Here we review the CTE literature to date. We also draw on the literature from mild traumatic brain injury and other neurodegenerative dementias, particularly when these studies provide guidance for future CTE research. We conclude by suggesting seven essential areas for future CTE research.

The National Football League and chronic traumatic encephalopathy: legal implications.

The growing awareness of chronic traumatic encephalopathy (CTE) has the potential to change the public perception and on-field rules of the National Football League (NFL). More than 3,000 ex-NFL players or their relatives are engaged in litigation alleging that the NFL failed to acknowledge and address the neuropsychiatric risks associated with brain injuries that result from playing in the NFL. This article explores the intersection between the medical and legal aspects of CTE in the NFL from a forensic psychiatry perspective.

Heart rate variability biofeedback, executive functioning and chronic brain injury.

PRIMARY OBJECTIVE: To determine if individuals with brain injury can modify heart rate variability (HRV) through biofeedback and, if so, enhance its pattern to improve emotional regulation and problem-solving ability. DESIGN: A quasi-experimental design with repeated measures was employed. Thirteen individuals aged 23-63 years with severe brain injury (13-40 years post-onset) participating in a community-based programme were enrolled. MAIN OUTCOMES: Response-to-treatment was measured with HRV indices, Behavior Rating Inventory of Executive Function (BRIEF-A-Informant) and attention/problem-solving tests. RESULTS: At post-treatment, HRV indices (Low Frequency/High Frequency [LF/HF] and coherence ratio) increased significantly. Increased LF/HF values during the second-half of a 10-minute session were associated with higher attention scores. Participants who scored better (by scoring lower) in informant ratings at pre-treatment had highest HRV scores at post-treatment. Accordingly, at post-treatment, families' ratings of participants' emotional control correlated with HRV indices; staffs' ratings of participants' working memory correlated with participants' HRV indices. Self-ratings of the BRIEF-A Task Monitoring scale at post-treatment correlated with family ratings at pre-treatment and post-treatment. CONCLUSIONS: Results demonstrate an association between regulation of emotions/cognition and HRV training. Individuals with severe, chronic brain injury can modify HRV through biofeedback. Future research should evaluate the efficacy of this approach for modifying behavioural problems.

Policy statement­Boxing participation by children and adolescents.

Thousands of boys and girls younger than 19 years participate in boxing in North America. Although boxing provides benefits for participants, including exercise, self-discipline, and self-confidence, the sport of boxing encourages and rewards deliberate blows to the head and face. Participants in boxing are at risk of head, face, and neck injuries, including chronic and even fatal neurologic injuries. Concussions are one of the most common injuries that occur with boxing. Because of the risk of head and facial injuries, the American Academy of Pediatrics and the Canadian Paediatric Society oppose boxing as a sport for children and adolescents. These organizations recommend that physicians vigorously oppose boxing in youth and encourage patients to participate in alternative sports in which intentional head blows are not central to the sport.

Cumulative head impact burden in high school football.

Impacts to the head are common in collision sports such as football. Emerging research has begun to elucidate concussion tolerance levels, but sub-concussive impacts that do not result in clinical signs or symptoms of concussion are much more common, and are speculated to lead to alterations in cerebral structure and function later in life. We investigated the cumulative number of head impacts and their associated acceleration burden in 95 high school football players across four seasons of play using the Head Impact Telemetry System (HITS). The 4-year investigation resulted in 101,994 impacts collected across 190 practice sessions and 50 games. The number of impacts per 14-week season varied by playing position and starting status, with the average player sustaining 652 impacts. Linemen sustained the highest number of impacts per season (868); followed by tight ends, running backs, and linebackers (619); then quarterbacks (467); and receivers, cornerbacks, and safeties (372). Post-impact accelerations of the head also varied by playing position and starting status, with a seasonal linear acceleration burden of 16,746.1g, while the rotational acceleration and HIT severity profile burdens were 1,090,697.7 rad/sec(2) and 10,021, respectively. The adolescent athletes in this study clearly sustained a large number of impacts to the head, with an impressive associated acceleration burden as a direct result of football participation. These findings raise concern about the relationship between sub-concussive head impacts incurred during football participation and late-life cerebral pathogenesis, and justify consideration of ways to best minimize impacts and mitigate cognitive declines.

Increased risk of schizophrenia following traumatic brain injury: a 5-year follow-up study in Taiwan.

BACKGROUND: Whether traumatic brain injury (TBI) is an independent risk factor for the subsequent development of schizophrenia has evoked considerable controversy. No evidence has been previously reported from Asia. This study estimated the risk of schizophrenia during a 5-year period following hospital admission for TBI relative to a comparison group of non-TBI patients during the same period in Taiwan. METHOD: Two datasets were linked: the Traumatic Brain Injury Registry and the Taiwan National Health Insurance Research Dataset. A total of 3495 patients hospitalized with a diagnosis of TBI from 2001 to 2002 were included, together with 17 475 non-TBI patients as the comparison group, matched on sex, age, and year of TBI hospitalization. Each individual was followed for 5 years to identify any later diagnosis of schizophrenia. Cox proportional hazard regressions were performed for analysis. RESULTS: During the 5-year follow-up period, patients who had suffered TBI were independently associated with a 1.99-fold (95% confidence interval 1.28-3.08) increased risk of subsequent schizophrenia, after adjusting for monthly income and residential geographical location. The severity and type of TBI was not associated with the subsequent development of schizophrenia. CONCLUSIONS: Our findings add important evidence from Asia and suggest a potential link between TBI and schizophrenia. Our study suggests that clinicians and family members should be alert to possible neuropsychiatric conditions following TBI.