Boxing and the brain

Preliminary Development of a Brainwave Model for K1 Kickboxers Using Quantitative Electroencephalography (QEEG) with Open Eyes

K1 kickboxing fighting is characterised by high injury rates due to the low restrictions of fighting rules. In recent years, much attention has been paid to research on changes in brain function among athletes, including those in combat sports. One of the tools that are likely to help diagnose and assess brain function is quantitative electroencephalography (QEEG). Therefore, the aim of the present study was an attempt to develop a brainwave model using quantitative electroencephalography in competitive K1 kickboxers. A total of thirty-six male individuals were purposefully selected and then comparatively divided into two groups. The first group consisted of specialised K1 kickboxing athletes exhibiting a high level of sports performance (experimental group, n = 18, mean age: 29.83 ± 3.43), while the second group comprised healthy individuals not training competitively (control group, n = 18, mean age: 26.72 ± 1.77). Body composition assessment was performed in all participants before the main measurement process. Measurements were taken for kickboxers during the de-training period, after the sports competition phase. Quantitative electroencephalography of Delta, Theta, Alpha, sensimotor rhytm (SMR), Beta1 and Beta2 waves was performed using electrodes placed on nine measurement points (frontal: FzF3F4, central: CzC3C4, and parietal: PzP3P4) with open eyes. In the course of the analyses, it was found that the level of brain activity among the study population significantly differentiated the K1 formula competitors compared with the reference standards and the control group in selected measurement areas. For kickboxers, all results of the Delta amplitude activity in the area of the frontal lobe were significantly above the normative values for this wave. The highest value was recorded for the average value of the F3 electrode (left frontal lobe), exceeding the norm by 95.65%, for F4 by 74.45% and Fz by 50.6%, respectively. In addition, the Alpha wave standard value for the F4 electrode was exceeded by 14.6%. Normative values were found for the remaining wave amplitudes. Statistically significant differentiation of results, with a strong effect (d = 1.52-8.41), was shown for the activity of Delta waves of the frontal area and the central part of the parietal area (Fz,F3,F4,Cz-p < 0.001), Theta for the frontal area as well as the central and left parietal lobes (Fz,F3,F4-p < 0.001, Cz-p = 0.001, C3-p = 0.018; d = 1.05-3.18), Alpha for the frontal, parietal and occipital areas (for: Fz,F3-p < 0.001, F4-p = 0.036, Cz-p < 0.001, C3-p = 0.001, C4-p = 0.025, Pz-p = 0.010, P3-p < 0.001, P4-p = 0.038; d = 0.90-1.66), SMR for the central parietal and left occipital lobes (Cz-p = 0.043; d = 0.69, P3-p < 0.001; d = 1.62), Beta for the frontal area, occipital and central lobes and left parietal segment (Fz,F3-p < 0.001, F4-p = 0.008, Cz, C3, Pz, P3,P4-p < 0.001; d = 1.27-2.85) and Beta 2 for all measurement areas (Fz, F3, F4, Cz, C3, C4, Pz, P3, P4-p < 0.001; d = 1.90-3.35) among the study groups. Significantly higher results were shown in the kickboxer group compared to the control. In addition to problems with concentration or over-stimulation of neural structures, high Delta waves, with elevated Alpha, Theta and Beta 2 waves, can cause disorders in the limbic system and problems in the cerebral cortex.

Comparison of Head Strike Incidence under K1 Rules of Kickboxing with and without Helmet Protection-A Pilot Study

BACKGROUND

Kickboxing is a combat sport that encompasses various forms of competition. K1 kickboxing is conducted without any restrictions on the force of strikes, and the bout can end prematurely through a knockout. Headgear has been introduced in amateur kickboxing to safeguard the head. However, scientific studies have shown that despite their use, serious head injuries can still occur. The aim of this study was to evaluate the temporal structure of the bout by calculating the number of head strikes in K1 kickboxing bouts with and without headgear.

METHODS

Thirty K1 kickboxing bouts were analyzed, with 30 participants included in the study. The fights were conducted according to the World Association Kickboxing Organization (WAKO) rules. The bouts consisted of three rounds of 2 min each, with a 1 min break between rounds. Sparring pairs were arranged according to weight categories. The first bouts were conducted without headgear, and two weeks later, the fights were repeated with WAKO-approved headgear. The number of head strikes was assessed retrospectively by analyzing video recordings of the bouts, categorizing strikes as hand or foot strikes, and differentiating between strikes that hit the head directly or indirectly.

RESULTS

The results showed statistically significant differences between bouts with and without headgear in terms of the number of strikes to the head (p = 0.002), strikes directly to the head (p < 0.001), all hand strikes to the head (p = 0.001), hand strikes directly to the head (p = 0.003), and foot strikes directly to the head (p = 0.03). Higher values were observed in bouts with headgear.

CONCLUSIONS

Headgear increases the probability of direct strikes to the head. Therefore, it is important to familiarize kickboxers with the use of headgear in their sport to minimize head injuries.

Cumulative Effect of Head Injuries on Nonmotor Outcomes in Parkinson's Disease

OBJECTIVE

Parkinson's disease (PD) is a neurodegenerative movement disorder that is a result of dopamine depletion in the basal ganglia. Individuals with a PD diagnosis experience motor symptoms (e.g., tremors) and nonmotor symptoms (e.g., cognitive decline). Previous studies suggest that progression of cognitive dysfunction in other neurologic populations can be predicted by cumulative head injuries. The study examined the association between lifelong number of head injuries and nonmotor outcomes (cognitive complaints, depression, and quality of life).

METHODS

Participants consisted of 3,483 individuals with PD diagnoses who were enrolled in the Fox Insight study. Participants completed a self-report questionnaire to quantify the number of head injuries experienced throughout life. Participants also completed measures of nonmotor outcomes (cognitive complaints, depression, and quality of life) every 6 months over a 3-year period.

RESULTS

Cognitive complaints were more common among those experiencing more head injuries. Further, more severe depression and greater difficulties in quality of life were reported among individuals experiencing a greater number of head injuries. Additional analyses revealed the effect between cognitive complaints and number of head injuries was driven by individuals who experienced five or more head injuries in their lifetime.

CONCLUSIONS

Among individuals with PD, a patient report of past head injuries may have prognostic implications for important nonmotor outcomes. Report of multiple head injuries may be particularly concerning.

The synapse in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and is a risk factor for dementia later in life. Research into the pathophysiology of TBI has focused on the impact of injury on the neuron. However, recent advances have shown that TBI has a major impact on synapse structure and function through a combination of the immediate mechanical insult and the ensuing secondary injury processes, leading to synapse loss. In this review, we highlight the role of the synapse in TBI pathophysiology with a focus on the confluence of multiple secondary injury processes including excitotoxicity, inflammation and oxidative stress. The primary insult triggers a cascade of events in each of these secondary processes and we discuss the complex interplay that occurs at the synapse. We also examine how the synapse is impacted by traumatic axonal injury and the role it may play in the spread of tau after TBI. We propose that astrocytes play a crucial role by mediating both synapse loss and recovery. Finally, we highlight recent developments in the field including synapse molecular imaging, fluid biomarkers and therapeutics. In particular, we discuss advances in our understanding of synapse diversity and suggest that the new technology of synaptome mapping may prove useful in identifying synapses that are vulnerable or resistant to TBI.

Life Expectancy of White and Non-White Elite Heavyweight Boxers

BACKGROUND

In post-industrial countries, ethnic minorities suffer poorer health and premature deaths. The present study examined ethnic differences in life expectancy and related features among elite heavyweight boxers.

METHODS

Dates of birth and death, anthropometry, and championship years were gathered from media archives for champions and challengers (never been a champion) between years 1889 and 2019. Cox regression adjusted for age at contest, nationality, BMI, champion/challenger status, and number of contests was used to assess survival.

RESULTS

All 237 boxers, 83 champions (37.3% whites) and 154 challengers (61.0% whites), who contested for heavyweight championships were identified. By 2019, 110 (75 whites, 34 non-whites) were known to have died. Non-white boxers died at an earlier age than whites boxers (mean ± SD = 59.8 ± 14.2 years versus 67.3 ± 16.4 years, p = 0.018) and had shorter survival: HR = 2.13 (95% CI = 1.4-3.3). Among non-white boxers, deaths were higher from neurological disorders: OR = 8.2 (95% CI = 1.3-13.5) and accidents: OR = 15.1 (95% CI = 2.3-98.2), while death from natural causes was lower: OR = 0.2 (95% CI = 0.03-0.8). After boxing careers, fewer non-white boxers had non-manual jobs (34.4% versus 71.8%) than manual (34.4% versus 19.7%) or were unemployed (28.1% versus 2.8%). Reported substance abuse was similar across ethnicity (8.0% versus 8.8%) but conviction rates were higher among non-white boxers (17.6%) than white (1.3%).

CONCLUSIONS

Compared with white boxers, non-white boxers tend to die younger with excess neurological and accidental deaths, and they have lower social positions in later life. Sporting authorities should reappraise the wisdom of permitting head injuries in sport and monitor and support the health and wellbeing of sports men and women after retirement.

Psychiatric sequelae of acquired brain injury

Improvements over recent decades in acute care of the brain-injured now ensure that all but the most severely injured survive. The legacy of that survival is an increasing number of people with enduring organic mental disorders. Here, I will focus upon the psychiatric sequelae of five types of severe single-insult brain injury: head trauma, subarachnoid haemorrhage, and hypoxic, hypoglycaemic and postencephalitic injury. Thrombotic stroke is a common and important cause of brain injury but the psychiatric consequences have been more extensively studied and are fairly well-known (Robinson & Price, 1982; Starkstein et al, 1987). Damage due to alcohol and associated malnutrition is also well-documented (Jacobson & Lishman, 1987, 1990). Neither will be specifically addressed here, though some of the consequences of brain injury are similar, regardless of cause.

Plasma creatine kinase B correlates with injury severity and symptoms in professional boxers

INTRODUCTION

Each year in the United States, approximately 1.7 million people sustain a traumatic brain injury (TBI). Of these TBI events, about 75 percent are characterized as being mild brain injuries. Immediately following TBI, a secondary brain damage persists for hours, days, and even months. Previously, detection of neuronal and glial biomarkers have proven to be useful to predict neurological outcomes. Here, we hypothesized that creatine kinase, brain (CKBB) is a sensitive biomarker for acute secondary brain injury in professional boxers.

METHODS

Blood (8cc) was collected from the boxing athletes (n=18) prior to and after competition (∼30min). The plasma levels of CKBB were measured using the Meso Scale Diagnostic (MSD) electrochemiluminescence (ECL) array-based multiplex format. Additional data such as number of blows to the head and symptom score (Rivermead Post Concussion Symptoms Questionnaire) were collected.

RESULTS

At approximately 30min after the competition, the plasma levels of CKBB were significantly elevated in concussed professional boxers and correlated with the number of blows to the head and symptom scores. Additionally, receiver operating curve (ROC) analysis yielded a 77.8% sensitivity and a specificity of 82.4% with an area under the curve (AUC) of 90% for CKBB as an identifier of secondary brain injury within this population.

CONCLUSION

This study describes the detection of CKBB as a brain biomarker to detect secondary brain injury in professional athletes that have experienced multiple high impact blows to the head. This acute biomarker may prove useful in monitoring secondary brain injury after injury.

Update on fluid biomarkers for concussion

Concussions are difficult to diagnose and symptoms may not appear immediately. As an accurate initial diagnosis has profound implications for the clinical management, there is an unmet need for better diagnostic tools. Fluid biomarkers for CNS injury may represent such tools. These markers are often proteins, peptides or other molecules with selective or high expression in the brain, which can be measured in the cerebrospinal fluid or blood as they leak out or get secreted into the biofluid in response to the injury. Here, we review the literature on fluid markers of neuronal, axonal and astroglial injury and response mechanisms to diagnose CNS injury upon head impact and to determine when the injurious process has resolved.

Head trauma in sport and neurodegenerative disease: an issue whose time has come?

A number of small studies and anecdotal reports have been suggested that sports involving repeated head trauma may have long-term risks of neurodegenerative disease. There are now plausible mechanisms for these effects, and a recognition that these problems do not just occur in former boxers, but in a variety of sports involving repeated concussions, and possibly also in sports in which low-level head trauma is common. These neurodegenerative effects potentially include increased risks of impaired cognitive function and dementia, Parkinson's disease, and amyotrophic lateral sclerosis. Many would argue for taking a precautionary approach and immediately banning or restricting sports such as boxing. However, there are important public health issues in terms of how wide the net should be cast in terms of other sports, and what remedial measures could be taken? This in turn requires a major research effort involving both clinical and basic research to understand the underlying mechanisms, leading from head trauma to neurodegenerative disease and epidemiologic studies to assess the long-term consequences.

Chronic traumatic encephalopathy: clinical-biomarker correlations and current concepts in pathogenesis

Background

Chronic traumatic encephalopathy (CTE) is a recently revived term used to describe a neurodegenerative process that occurs as a long term complication of repetitive mild traumatic brain injury (TBI). Corsellis provided one of the classic descriptions of CTE in boxers under the name “dementia pugilistica” (DP). Much recent attention has been drawn to the apparent association of CTE with contact sports (football, soccer, hockey) and with frequent battlefield exposure to blast waves generated by improvised explosive devices (IEDs). Recently, a promising serum biomarker has been identified by measurement of serum levels of the neuronal microtubule associated protein tau. New positron emission tomography (PET) ligands (e.g., [¹⁸ F] T807) that identify brain tauopathy have been successfully deployed for the in vitro and in vivo detection of presumptive tauopathy in the brains of subjects with clinically probable CTE.

Methods

Major academic and lay publications on DP/CTE were reviewed beginning with the 1928 paper describing the initial use of the term CTE by Martland.

Results

The major current concepts in the neurological, psychiatric, neuropsychological, neuroimaging, and body fluid biomarker science of DP/CTE have been summarized. Newer achievements, such as serum tau and [¹⁸ F] T807 tauopathy imaging, are also introduced and their significance has been explained.

Conclusion

Recent advances in the science of DP/CTE hold promise for elucidating a long sought accurate determination of the true prevalence of CTE. This information holds potentially important public health implications for estimating the risk of contact sports in inflicting permanent and/or progressive brain damage on children, adolescents, and adults.

Clinical comparison of 99mTc exametazime and 123I Ioflupane SPECT in patients with chronic mild traumatic brain injury

Background

This study evaluated the clinical interpretations of single photon emission computed tomography (SPECT) using a cerebral blood flow and a dopamine transporter tracer in patients with chronic mild traumatic brain injury (TBI). The goal was to determine how these two different scan might be used and compared to each other in this patient population.

Methods and Findings

Twenty-five patients with persistent symptoms after a mild TBI underwent SPECT with both ^99mTc exametazime to measure cerebral blood flow (CBF) and ¹²³I ioflupane to measure dopamine transporter (DAT) binding. The scans were interpreted by two expert readers blinded to any case information and were assessed for abnormal findings in comparison to 10 controls for each type of scan. Qualitative CBF scores for each cortical and subcortical region along with DAT binding scores for the striatum were compared to each other across subjects and to controls. In addition, symptoms were compared to brain scan findings. TBI patients had an average of 6 brain regions with abnormal perfusion compared to controls who had an average of 2 abnormal regions (p<0.001). Patient with headaches had lower CBF in the right frontal lobe, and higher CBF in the left parietal lobe compared to patients without headaches. Lower CBF in the right temporal lobe correlated with poorer reported physical health. Higher DAT binding was associated with more depressive symptoms and overall poorer reported mental health. There was no clear association between CBF and DAT binding in these patients.

Conclusions

Overall, both scans detected abnormalities in brain function, but appear to reflect different types of physiological processes associated with chronic mild TBI symptoms. Both types of scans might have distinct uses in the evaluation of chronic TBI patients depending on the clinical scenario.

Acute and chronic traumatic encephalopathies: pathogenesis and biomarkers

Over the past decade, public awareness of the long-term pathological consequences of traumatic brain injury (TBI) has increased. Such awareness has been stimulated mainly by reports of progressive neurological dysfunction in athletes exposed to repetitive concussions in high-impact sports such as boxing and American football, and by the rising number of TBIs in war veterans who are now more likely to survive explosive blasts owing to improved treatment. Moreover, the entity of chronic traumatic encephalopathy (CTE)--which is marked by prominent neuropsychiatric features including dementia, parkinsonism, depression, agitation, psychosis, and aggression--has become increasingly recognized as a potential late outcome of repetitive TBI. Annually, about 1% of the population in developed countries experiences a clinically relevant TBI. The goal of this Review is to provide an overview of the latest understanding of CTE pathophysiology, and to delineate the key issues that are challenging clinical and research communities, such as accurate quantification of the risk of CTE, and development of reliable biomarkers for single-incident TBI and CTE.

From Concussion to Chronic Traumatic Encephalopathy: A Review

Sports-related activities account for an estimated 10% of head and spinal cord injuries. In recent years, concussion in particular has garnered more interest in the medical field as well as the media. Reports of athletes suffering from long-term cognitive deficits and Parkinsonian symptoms have sparked concern in a disease process that has often been underestimated or ignored. As more reports surface, the desperate need for a better understanding of the neuropathology has been made clear. In addition to the concern for acute injury, long-term sequelae such as chronic traumatic encephalopathy (CTE) are feared consequences of concussive injuries. Research studies have shown significant overlap in the neuropathology between CTE and chronic neurodegenerative processes such as Alzheimer’s disease (AD). In particular, tau protein deposition has been found to be present in both disease processes and may play an important part in the clinical findings observed. The present review discusses concussion and our current understanding of pathological findings that may underlie the clinical features associated with concussive injuries and resulting chronic traumatic encephalopathy.

Frontal cortex neuropathology in dementia pugilistica

Dementia pugilistica (DP) is associated with chronic traumatic brain injury (CTBI), and leads to a "punch drunk" syndrome characterized by impairments in memory and executive function, behavioral changes, and motor signs. Microscopic features include the accumulation of neurofibrillary tangles (NFTs), beta-amyloid (Aβ), and TAR DNA binding protein 43 (TDP-43) pathology. Here we describe detailed clinical and neuropathological data about a 55-year-old retired boxer (ApoE3/4), who presented with executive dysfunction and behavioral impairments. At autopsy, significant Aβ pathology was seen, primarily in the form of diffuse plaques. Tau pathology was extensive and was determined to be of Braak and Braak stage VI. Frontal white matter showed evidence of glial tau inclusions (astrocytes and oligodendroglia). Cerebrovascular pathology was minimal with patchy amyloid angiopathy. Inflammation was another key feature, including microglial activation and significant C1q labeling of neurons, along with NFTs. TDP-43-positive pathology was also observed. Inflammation may be a key inciting as well as propagating feature of DP neuropathology.

Inhibition of JNK by a peptide inhibitor reduces traumatic brain injury-induced tauopathy in transgenic mice

Traumatic brain injury (TBI) is a major environmental risk factor for subsequent development of Alzheimer disease (AD). Pathological features that are common to AD and many tauopathies are neurofibrillary tangles (NFTs) and neuropil threads composed of hyperphosphorylated tau. Axonal accumulations of total and phospho-tau have been observed within hours to weeks, and intracytoplasmic NFTs have been documented years after severe TBI in humans. We previously reported that controlled cortical impact TBI accelerated tau pathology in young 3xTg-AD mice. Here, we used this TBI mouse model to investigate mechanisms responsible for increased tau phosphorylation and accumulation after brain trauma. We found that TBI resulted in abnormal axonal accumulation of several kinases that phosphorylate tau. Notably, c-Jun N-terminal kinase (JNK) was markedly activated in injured axons and colocalized with phospho-tau. We found that moderate reduction of JNK activity (40%) by a peptide inhibitor, D-JNKi1, was sufficient to reduce total and phospho-tau accumulations in axons of these mice with TBI. Longer-term studies will be required to determine whether reducing acute tau pathology proves beneficial in brain trauma.

Controlled cortical impact traumatic brain injury in 3xTg-AD mice causes acute intra-axonal amyloid-β accumulation and independently accelerates the development of tau abnormalities

Alzheimer's disease (AD) is a neurodegenerative disorder characterized pathologically by progressive neuronal loss, extracellular plaques containing the amyloid-β (Aβ) peptides, and neurofibrillary tangles composed of hyperphosphorylated tau proteins. Aβ is thought to act upstream of tau, affecting its phosphorylation and therefore aggregation state. One of the major risk factors for AD is traumatic brain injury (TBI). Acute intra-axonal Aβ and diffuse extracellular plaques occur in ∼30% of human subjects after severe TBI. Intra-axonal accumulations of tau but not tangle-like pathologies have also been found in these patients. Whether and how these acute accumulations contribute to subsequent AD development is not known, and the interaction between Aβ and tau in the setting of TBI has not been investigated. Here, we report that controlled cortical impact TBI in 3xTg-AD mice resulted in intra-axonal Aβ accumulations and increased phospho-tau immunoreactivity at 24 h and up to 7 d after TBI. Given these findings, we investigated the relationship between Aβ and tau pathologies after trauma in this model by systemic treatment of Compound E to inhibit γ-secretase activity, a proteolytic process required for Aβ production. Compound E treatment successfully blocked posttraumatic Aβ accumulation in these injured mice at both time points. However, tau pathology was not affected. Our data support a causal role for TBI in acceleration of AD-related pathologies and suggest that TBI may independently affect Aβ and tau abnormalities. Future studies will be required to assess the behavioral and long-term neurodegenerative consequences of these pathologies.

Neurofibrillary tangle pathology and Braak staging in chronic epilepsy in relation to traumatic brain injury and hippocampal sclerosis: a post-mortem study

The long-term pathological effects of chronic epilepsy on normal brain ageing are unknown. Previous clinical and epidemiological studies show progressive cognitive decline in subsets of patients and an increased prevalence of Alzheimer's disease in epilepsy. In a post-mortem series of 138 patients with long-term, mainly drug-resistant epilepsy, we carried out Braak staging for Alzheimer's disease neurofibrillary pathology using tau protein immunohistochemistry. The stages were compared with clinicopathological factors, including seizure history and presence of old traumatic brain injury. Overall, 31% of cases were Braak Stage 0, 36% Stage I/II, 31% Stage III/IV and 2% Stage V/VI. The mean age at death was 56.5 years and correlated with Braak stage (P < 0.001). Analysis of Braak stages within age groups showed a significant increase in mid-Braak stages (III/IV), in middle age (40-65 years) compared with data from an ageing non-epilepsy series (P < 0.01). There was no clear relationship between seizure type (generalized or complex partial), seizure frequency, age of onset and duration of epilepsy with Braak stage although higher Braak stages were noted with focal more than with generalized epilepsy syndromes (P < 0.01). In 30% of patients, there was pathological evidence of traumatic brain injury that was significantly associated with higher Braak stages (P < 0.001). Cerebrovascular disease present in 40.3% and cortical malformations in 11.3% were not significantly associated with Braak stage. Astrocytic-tau protein correlated with the presence of both traumatic brain injury (P < 0.01) and high Braak stage (P < 0.001). Hippocampal sclerosis, identified in 40% (bilateral in 48%), was not associated with higher Braak stages, but asymmetrical patterns of tau protein accumulation within the sclerotic hippocampus were noted. In over half of patients with cognitive decline, the Braak stage was low indicating causes other than Alzheimer's disease pathology. In summary, there is evidence of accelerated brain ageing in severe chronic epilepsy although progression to high Braak stages was infrequent. Traumatic brain injury, but not seizures, was associated with tau protein accumulation in this series. It is likely that Alzheimer's disease pathology is not the sole explanation for cognitive decline associated with epilepsy.

Sports concussion and the risk of chronic neurological impairment

Intense recent media focus on long-term outcomes from sports concussion has highlighted concerns on both cognitive deterioration and mental health issues, such as depression and suicide. At this time, the scientific evidence to support these views is limited, with only a handful of cases thus far reported. Based on the literature on this topic that extends back over 50 years, it is clear that only a small percentage of athletes suffer such sequelae presumably due to recurrent concussive or subconcussive head impacts. At this stage, determining which athletes are at future risk is not possible; however, following existing concussion guidelines (eg, Zurich guidelines) is likely to be the safest option based on current evidence.

Cerebral microhemorrhages detected by susceptibility-weighted imaging in amateur boxers

BACKGROUND AND PURPOSE

SWI is a new technique for evaluating diffuse axonal injury associated with punctate hemorrhages. The aim of our study was to determine the prevalence of cerebral microhemorrhages in amateur boxers compared with nonboxers by using SWI and to evaluate the sensitivity of SWI compared with T2 FSE and T2*GE sequences.

MATERIALS AND METHODS

We performed cranial MR imaging with a 1.5T scanner in 21 amateur boxers and 21 control subjects. The study protocol included conventional MR images, T2 FSE, T2*GE, and SWI sequences. The proportions of boxers and controls having CSP, DPVS, cerebral atrophy, cerebellar atrophy, ventricular dilation, PSWMD, and microhemorrhages were computed and were compared by using the χ(2) test of proportions. The relationship between microhemorrhages and boxing-related covariates was assessed by using the Wilcoxon rank sum test. The association between the categories was tested by using the Fisher exact test.

RESULTS

Using SWI, microhemorrhages were found in 2 (9.52%) of 21 boxers. The microhemorrhages were not visible on T2 FSE or T2*GE images. The proportion of subjects with microhemorrhages did not differ significantly between the boxers and control subjects (χ(2) = 0.525, df = 1, P = .4688). The prevalence of CSP and DPVS was significantly higher in the boxers than in the control subjects.

CONCLUSIONS

More microhemorrhages were detected in amateur boxers than in controls, but this difference was not statistically significant.

Neuropathology of epilepsy and psychosis: the contributions of J.A.N. Corsellis

Professor J.A.N. Corsellis, whose life and work is recalled here, gained great insight into the meaning of morphological cerebral aberrations found in neuropsychiatric disease through exact neuropathological investigations of tissue specimens obtained from patients with distinct syndromes. He was a leading authority in the field. We have searched and compiled resources relating to J.A.N. Corsellis' life and work, including personal memories from colleagues and data from scientific publications. J.A.N. Corsellis made seminal contributions to the understanding of neuropsychiatric disease; his works substantially added to the understanding of the dementias, schizophrenia and the psychoses, and morphological sequelae of boxing. In seizure disorders, his name is linked to the first description of focal cortical dysplasia and limbic encephalitis, the pathology of status epilepticus and Ammon's horn sclerosis, and the systematic investigation of epilepsy surgery specimens in general. Both his life and work are closely linked to Runwell Hospital, Wickford, Essex and the Maudsley Hospital. During his professional life he established a large brain bank, now known as the Corsellis Collection. J.A.N. Corsellis had significant impact on neuroscience; many of his observations were groundbreaking and are still valid.

Abnormal TDP-43 expression is identified in the neocortex in cases of dementia pugilistica, but is mainly confined to the limbic system when identified in high and moderate stages of Alzheimer's disease

The transactive response (TAR) DNA binding protein TDP-43 has been discovered to be a major ubiquitinated protein in frontotemporal lobar degeneration with ubiquitinated tau-negative inclusions (FTLD-U), which consequently has been renamed FTLD-TDP. However, TDP-43 has since been detected in conditions such as Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) but is often confined to the limbic region rather than the more widespread pattern seen in FTLD-TDP. Previous work has suggested some relationship between hippocampal sclerosis and TDP-43 expression. A number of AD cases of both moderate and high stage were examined to determine whether the pattern of TDP-43 immunohistochemical expression differed and whether any relationship to hippocampal sclerosis could be detected. Cases of hippocampal sclerosis from surgical epilepsy specimens were examined to determine whether hippocampal sclerosis alone could cause abnormal TDP-43 expression. To establish whether abnormal TDP-43 expression in other neurodegenerative diseases resembled the pattern and distribution in FTLD-TDP we examined multiple blocks from a variety of neurodegenerative conditions. In 75% of cases of high-stage AD there was abnormal TDP-43 positivity compared to 57% of moderate-stage AD. While the abnormal TDP-43 positivity was confined to the limbic regions in the moderate stages, occasional cases in the high stages showed neocortical positivity. Also amygdala and/or entorhinal positivity appeared to precede positivity in the dentate gyrus. No relationship could be established between abnormal TDP-43 expression and degree of hippocampal sclerosis either in the surgical or autopsy cases. The pattern of distribution of TDP-43 inclusions from cases of dementia pugilistica most closely resembled that in FTLD-TDP. This raises the question as to whether there may be some shared pathogenic mechanisms between the two conditions.

The Evidence for Chronic Traumatic Encephalopathy in Boxing

The sport of boxing has been the source of much debate, with concerns about the neurological risks of participating having led to many calls to ban the sport. This review seeks to establish an evidence base for the development of boxing-related chronic traumatic encephalopathy (CTE) and to determine the relevance of this information to the modern day sport.The clinical features of CTE include various symptoms affecting the pyramidal and extrapyramidal systems, which manifest most often as disturbed gait and coordination, slurred speech and tremors, as well as cerebral dysfunction causing cognitive impairments and neurobehavioural disturbances. Both amateur and professional boxers are potentially at risk of developing CTE. No current epidemiological evidence exists to determine the prevalence of this condition in modern day boxing, despite 17% of professional boxers in Britain with careers in the 1930-50s having clinical evidence of CTE. As medical presence within the sport increases and with modern boxers likely to have shorter careers, a reduced exposure to repetitive head trauma, and improved treatment and understanding of the development of CTE will occur. This should lead to the incidence of CTE diminishing in boxing populations.

Diffusion anisotropy changes in the brains of professional boxers

BACKGROUND AND PURPOSE

Professional boxing may result in brain injury. We hypothesize that quantitative MR diffusion imaging may be useful in determining early white matter changes.

METHODS

Forty-nine professional boxers (age 30 +/- 4.5 years) and 19 healthy control subjects (age 32 +/- 9.5 years) were imaged on a clinical 1.5T scanner. None of the subjects had neurologic disorder or deficit. The average diffusion constant (D(av)) and diffusion anisotropy (FA) were determined pixel by pixel. Regional diffusion measurements were done in the corpus callosum (CC) and internal capsule (IC). The whole brain diffusion constant (BD(av)) was also determined. Student t test was used to analyze the diffusion difference between boxers and the healthy control subjects. P < .05 was considered statistically significant.

RESULTS

Of the 49 professional boxers, 42 had normal conventional MRIs. The remaining 7 boxers had abnormal MR imaging findings dominated by nonspecific white matter disease. There was a significant difference in diffusion and anisotropy measurements in all the boxers compared with the healthy control subjects. In the boxer group, BD(av) increased and FA decreased significantly in the CC and posterior limb of IC. The measured FA and D(av) inversely correlated in regions of CC and IC in boxers but not in healthy control subjects. BD(av) also robustly correlated with both FA and D(av) in the splenium of CC in boxers.

CONCLUSION

Increased BD(av) and the decreased FA in the CC and IC may represent preclinical signs of subtle brain injury in professional boxers.

Concussion in professional football: comparison with boxing head impacts--part 10

OBJECTIVE

This study addresses impact biomechanics from boxing punches causing translational and rotational head acceleration. Olympic boxers threw four different punches at an instrumented Hybrid III dummy and responses were compared with laboratory-reconstructed NFL concussions.

METHODS

Eleven Olympic boxers weighing 51 to 130 kg (112-285 lb) delivered 78 blows to the head of the Hybrid III dummy, including hooks, uppercuts and straight punches to the forehead and jaw. Instrumentation included translational and rotational head acceleration and neck loads in the dummy. Biaxial acceleration was measured in the boxer's hand to determine punch force. High-speed video recorded each blow. Hybrid III head responses and finite element (FE) brain modeling were compared to similarly determined responses from reconstructed NFL concussions.

RESULTS

The hook produced the highest change in hand velocity (11.0 +/- 3.4 m/s) and greatest punch force (4405 +/- 2318 N) with average neck load of 855 +/- 537 N. It caused head translational and rotational accelerations of 71.2 +/- 32.2 g and 9306 +/- 4485 r/s. These levels are consistent with those causing concussion in NFL impacts. However, the head injury criterion (HIC) for boxing punches was lower than for NFL concussions because of shorter duration acceleration. Boxers deliver punches with proportionately more rotational than translational acceleration than in football concussion. Boxing punches have a 65 mm effective radius from the head cg, which is almost double the 34 mm in football. A smaller radius in football prevents the helmets from sliding off each other in a tackle.

CONCLUSION

Olympic boxers deliver punches with high impact velocity but lower HIC and translational acceleration than in football impacts because of a lower effective punch mass. They cause proportionately more rotational acceleration than in football. Modeling shows that the greatest strain is in the midbrain late in the exposure, after the primary impact acceleration in boxing and football.

The septum pellucidum and its variants. An MRI study

PURPOSE

Increased prevalence of cavum septi pellucidi (CSP) in schizophrenic patients in comparison to healthy subjects was reported previously. Our purpose was to evaluate the prevalence of variants of the septum pellucidum in healthy subjects in three different age groups.

METHODS

151 healthy subjects, including 46 children (age 6 +/- 4 years), 72 young adults (age 31 +/- 8 years) and 33 elderly adults (age 59 +/- 7 years) were examined with high-resolution MRI. Three observers analysed the images using a standardised protocol. We evaluated the incidences of CSP, cavum vergae (CV) and their length.

RESULTS

CSP was detected in 80% of the cases in the paediatric group and 68% of young adults and in 72% of the elderly adults. A cavum vergae (CV) was noted in 22% of the children, in 39% of the young adults and in 36% of the elderly subjects. There was no significant difference between the age-related groups.

CONCLUSION

We detected a high prevalence of cavum septi pellucidi without a significant age dependence. Enlarged cava septi pellucidi are rare in healthy subjects.

Long term neuropsychological outcome after head injury: relation to APOE genotype

BACKGROUND

Existing evidence suggests that some patients who sustain a head injury suffer cognitive decline many years later, and that head injury and possession of the APOE epsilon 4 allele are each risk factors for Alzheimer's disease.

OBJECTIVE

To determine whether late cognitive decline after head injury is more prevalent among carriers of APOE epsilon 4.

METHODS

A database of head injured patients was used. Initial assessment was at the time of their injury, between 1968 and 1985, and outcome data at six months were available. Their ages at the time of injury ranged between 2 and 70 years. A cohort of 396 subjects was reassessed at a mean of 18 years later, with determination of APOE genotype and detailed neuropsychological testing.

RESULTS

Judging by the Glasgow outcome scale, twice as many patients had deteriorated as improved between six months after injury and the late assessment; 22.2% of APOE epsilon 4 carriers had a good late outcome compared with 30.5% of non-carriers (95% confidence interval for the difference, -0.7% to 17.2%; p = 0.084). There were no clear differences between epsilon 4 carriers and non-carriers in detailed neuropsychological assessments.

CONCLUSIONS

Although this study provides additional evidence that a late decline may occur after head injury, there was no clear relation to APOE genotype. Despite the follow up interval of 15 to 25 years, the cohort is still too young (mean age 42.1 years) to assess the risk of Alzheimer's disease.

Increased diffusion in the brain of professional boxers: a preclinical sign of traumatic brain injury?

BACKGROUND AND PURPOSE

Professional boxing is associated with chronic, repetitive head blows that may cause brain injuries. Diffusion-weighted imaging is sensitive to microscopic changes and may be a useful tool to quantify the microstructural integrity of the brain. In this study, we sought to quantify microscopic alterations associated with chronic traumatic brain injury in professional boxers.

METHODS

MR and diffusion-weighted imaging were performed in 24 boxers and in 14 age- and sex-matched control subjects with no history of head trauma. Using distribution analysis, the average diffusion constant of the entire brain (BD(av)) and diffusion distribution width (sigma) were calculated for each subject; findings in professional boxers were compared with those of control subjects. In the boxer group, correlations between diffusion changes and boxing history and diffusion changes and MR imaging findings were assessed.

RESULTS

The measured diffusion values in the boxer group were significantly higher than those measured in the control group (BD(av), P <.0001; sigma, P <.01). In the boxer group, a robust correlation was found between increased BD(av) and frequency of hospitalization for boxing injuries (r = 0.654, P <.05). The most common MR finding in the boxer group was volume loss inappropriate to age followed by cavum septum pellucidum, subcortical white matter disease, and periventricular white matter disease.

CONCLUSION

Boxers had higher diffusion constants than those in control subjects. Our data suggest that microstructural damage of the brain associated with chronic traumatic brain injury may elevate whole-brain diffusion. This global elevation can exist even when routine MR findings are normal.

Pathology of head trauma

This article reviews the essential primary and secondary injuries attributable to traumatic brain injury (TBI) which causes one third of all injury deaths in the United States. Motor vehicle crashes, falls, assaults, guns, sports, and recreational activities are the major causes of TBI. Secondary peak incidences of TBI occur in infants and children and the elderly. Conditions that increase risk for accidents include alcoholism, prior head injury, prior meningitis, seizure disorders, mental retardation, and psychiatric disorders. However, gunshot wounds to the head are steadily increasing and since 1990 have caused more deaths each year than motor vehicle accidents. The incidence, severity, etiology, and specific types of injuries have been assessed in clinicopathologic studies of head injuries. The pathologic features of both the primary and secondary lesions attributed to TBI should be understood by anyone caring for head-injured patients. The computed tomography (CT) and magnetic resonance (MR) images mirror the pathologic abnormalities found in head trauma. Radiologists must accurately interpret the CT and MR images of injured patients. Forensic pathologists have long appreciated the characteristic focal lesions, such as coup and contracoup contusions, that occur in falls or vehicle accidents, but the understanding of diffuse injuries has been more elusive. Understanding the nature of the focal and diffuse injuries is critical to understanding the morbidity and mortality of brain injury.

Recent advances in neurotrauma

The frequency of and outcome from acute traumatic brain injury (TBI) in humans are detailed together with a classification of the principal focal and diffuse pathologies, and their mechanisms in extract laboratory models are outlined. Particular emphasis is given to diffuse axonal injury, which is a major determinant of outcome. Cellular and molecular cascades triggered by injury are described with reference to the induction of axolemmal and cytoskeletal abnormalities, necrotic and apoptotic cell death, the role of Ca2+, cytokines and free radicals, and damage to DNA. It is concluded that TBI in humans is heterogeneous, reflecting various pathologies in differing proportions in patients whose genetic background (APOE gene polymorphisms) contributes to the outcome at 6 months. Although considerable progress has been made in the understanding of TBI, much remains to be determined. However, a deeper understanding of the pathophysiological events may lead to the possibility of improving outcome from rational targeted therapy.

Sport psychiatry

OBJECTIVE

The aim of this article is to provide an overview of the literature on psychiatry for elite athletes.

METHOD

Relevant literature was presented to the general psychiatrist.

RESULTS

The prevalence of drug misuse, eating disorders and brain injury in elite and professional athletes is stressed. The uniquely troublesome adverse effects of psychopharmacology in this group of subjects is commented upon.

CONCLUSIONS

Elite athletes may require competent and informed psychiatric opinion and management.

Dementia pugilistica in an alcoholic achondroplastic dwarf

Dementia pugilistica is classically seen in boxers. We describe the case of a 33-yr-old achondroplastic dwarf who developed the pathological hallmarks of the condition, probably as a result of chronic occupational trauma. Dementia pugilistica has not been previously described in achondroplasia.

The neuropsychiatric aspects of boxing

OBJECTIVE

To review the neuropsychiatry of boxing.

METHOD

This update considers the clinical, neuropsychological, diagnostic, neurobiological, and management aspects of boxing-related brain injury.

RESULTS

Professional boxers with multiple bouts and repeated head blows are prone to chronic traumatic encephalopathy (CTE). Repeated head blows produce rotational acceleration of the brain, diffuse axonal injury, and other neuropathological features. CTE includes motor changes such as tremor, dysarthria, and parkinsonism; cognitive changes such as mental slowing and memory deficits; and psychiatric changes such as explosive behavior, morbid jealousy, pathological intoxication, and paranoia. Screening with neuropsychological tests and neuroimaging may help predict those boxers at risk for CTE.

CONCLUSIONS

Boxing results in a spectrum of CTE ranging from mild, nonprogressive motor changes to dementia pugilistica. Recent emphasis on safety in the ring, rehabilitation techniques, and other interventions do not eliminate the risk for CTE. For this reason, there is an active movement to ban boxing.

Neuropsychological investigation of amateur boxers

Amateur boxing is faced with criticism over the potential damage the sport inflicts on those who participate. The most sensitive measure of early neurological dysfunction is neuropsychological investigation. Ten studies employing such assessments on 289 amateur boxers are reviewed. The forms of analysis undertaken include controlled comparison with other sportsmen, of both active and former boxers, detailed pre- and post-bout analysis, analysis of the influence of within-boxing variables, length of career, level of competition and prospective longitudinal investigation. Amateur boxers were found to exhibit no signs of neuropsychological dysfunction in any analysis. However some trends emerged suggesting a long career in amateur boxing might reduce fine motor reactions, although such findings are within the normal range and do not represent central neuropsychological functioning. Thus amateur boxing does not appear to expose individuals to neurological dysfunction.

A prospective controlled investigation of the cognitive effects of amateur boxing

Eighty six amateur boxers underwent a series of neuropsychological assessments on three occasions--pre bout, immediate post bout and follow up within two years; 31 water polo players and 47 rugby union players acted as controls. The neuropsychological tests were selected as being sensitive to subtle cognitive dysfunction and formed part of a battery of other neurological and ophthalmic assessments. No evidence of neuropsychological dysfunction due to boxing was found, either following a bout or a series of bouts at follow up. None of a range of parameters including number of previous contests, recovery from an earlier bout, number of head blows received during a bout and number of bouts between initial assessment and follow up, were found to be related to changes in cognitive functioning.

Does amateur boxing lead to chronic brain damage? A review of some recent investigations

Fifty former amateur boxers were examined and compared with two control groups of soccer players and track and field athletes. All subjects were interviewed regarding their sports career, medical history, and social variables. They underwent a physical and a neurologic examination. Personality traits were investigated and related to the platelet monoamine oxidase activity. Cerebral morphologic changes were evaluated using computed tomography and magnetic resonance imaging. Further, clinical neurophysiologic tests were made as well as neuropsychologic tests. No significant differences were found between the groups in any of the physical or neurologic examinations or in platelet monoamine oxidase activity. Socially, the boxers had a lower degree of education and had chosen less intellectual professions, but they were less impulsive and more socialized. The computed tomography images and magnetic resonance imaging studies showed no significant differences between the groups. There was a significantly higher incidence of slight or moderate electroencephalography deviations among the boxers. Neuropsychologically, the boxers had an inferior finger-tapping performance. Thus, no signs of serious chronic brain damage were found among any of the groups studied. However, the electroencephalography and finger-tapping differences between the groups might indicate slight brain dysfunction in some of the amateur boxers.

Does Swedish amateur boxing lead to chronic brain damage? 3. A retrospective clinical neurophysiological study

The aim of the present study was to investigate possible chronic brain damage due to Swedish amateur boxing. Forty seven former amateur boxers, 22 with many (HM = high-matched) and 25 with few matches (LM = low-matched) during their career were examined and compared with two control groups of 25 soccer players and 25 track and field athletes in the same age-range. No severe EEG abnormality was found. There was a somewhat higher incidence of slight or moderate EEG deviations among HM-(32%, 7/22) and LM-(36%, 9/25) boxers than among soccer players (20%, 5/25) and track and field athletes (12%, 3/25). Brain electric activity mapping (BEAM), brainstem auditory evoked potential (BAEP) and auditory evoked P 300 potential (P 300) did not differ significantly between the groups. No neurophysiological variable was correlated to the number of bouts, number of lost fights or length of boxing career. Thus, no signs of serious chronic brain damage was found among the amateur boxers or the soccer players and the track and field athletes. However, it cannot be excluded that the EEG differences between the groups may be a sign of slight brain dysfunction in some of the amateur boxers.