Barry D. Jordan

Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012

This paper is a revision and update of the recommendations developed following the 1st (Vienna 2001), 2nd (Prague 2004) and 3rd (Zurich 2008) International Consensus Conferences on Concussion in Sport and is based on the deliberations at the 4th International Conference on Concussion in Sport held in Zurich, November 2012.1–3 The new 2012 Zurich Consensus statement is designed to build on the principles outlined in the previous documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the Background section. This document is developed primarily for use by physicians and healthcare professionals who are involved in the care of injured athletes, whether at the recreational, elite or professional level. While agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving, and therefore management and return to play (RTP) decisions remain in the realm of clinical judgement on an individualised basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document, the Concussion Recognition Tool (CRT), the Sports Concussion Assessment Tool V.3 (SCAT3) and/or the Child SCAT3 card and none are subject to any restrictions, provided they are not altered in any way or converted to a digital format. The authors request that the document and/or the accompanying tools be distributed in their full and complete format. This consensus paper is broken into a number of sections 1. A summary of concussion and its management, with updates from the previous meetings; 2. Background information about the consensus meeting process; 3. A summary of the specific consensus questions discussed at this meeting; 4. The Consensus paper should be read in conjunction with the SCAT3 assessment tool, the Child SCAT3 and the CRT …

Vacuolar Myelopathy Pathologically Resembling Subacute Combined Degeneration in Patients with the Acquired Immunodeficiency Syndrome

Twenty of 89 consecutive patients with the acquired immunodeficiency syndrome (AIDS) in whom autopsies were performed over a 3 1/2-year period had a vacuolar myelopathy that was most severe in the lateral and posterior columns of the thoracic cord. Light and electron microscopy showed that vacuoles were surrounded by a thin myelin sheath and appeared to arise from swelling within myelin sheaths. Signs and symptoms referable to the spinal-cord lesions, including paraparesis, often accompanied by spasticity or ataxia (or both), were present in all five patients with marked pathological changes, in five of seven patients with moderate changes, and in two of eight patients with mild changes. Fourteen patients were demented. The clinical presentation was sufficiently distinctive to provide a guide for antemortem diagnosis. Possible causes of the vacuolar changes include uncharacterized viral infection or a metabolic derangement related to selective nutritional deficiency.

Prolonged effects of concussion in high school athletes.

OBJECTIVE:To identify enduring prolonged neuropsychological effects of cerebral concussion in high school youth athletes. METHODS:High school athletes (n = 223) underwent baseline neuropsychological evaluation between 1999 and 2000, assigned to independent groups on the basis of concussion history: athletes with no concussion history or present medical and/or neuropsychological complaints (n = 82), symptom-free athletes who experienced one (n = 56) or two or more (n = 45) concussions (not in the prior 6 mo), and those who experienced a concussion 1 week before testing (n = 40). Main outcome measures included a structured clinical interview, demographic form, symptom checklist, the Repeatable Battery for the Assessment of Neuropsychological Status, and the Trail Making Tests A and B. Analyses of variance were used to determine between-group differences. RESULTS:Athletes with recent concussions performed significantly worse on measures of attention and concentration than youth athletes with no concussion history. Symptom-free athletes with a history of two or more concussions performed similar on testing to youth athletes who had just experienced a recent concussion. Similarly, cumulative academic grade point averages were significantly lower not only for youth athletes with two or more previous concussion groups, but for youth athletes who experienced recent concussions, suggesting that athletes with lower grade point averages may be more prone to concussion. CONCLUSION:There seem to be subtle yet significant prolonged neuropsychological effects in youth athletes with a history of two or more previous concussions.

Consensus statement on concussion in sport: the 4th international conference on concussion in sport, Zurich, november 2012

Paul McCrory, MBBS, PhD*; Willem H. Meeuwisse, MD, PhD†; Mark Aubry, MD‡; Robert C. Cantu, MD§; Jiři Dvořak, MD||; Ruben J. Echemendia, PhD¶; Lars Engebretsen, MD, PhD#; Karen Johnston, MD, PhD**; Jeffrey S. Kutcher, MD††; Martin Raftery, MBBS‡‡; Allen Sills, MD§§; Brian W. Benson, MD, PhD||||; Gavin A. Davis, MBBS¶¶; Richard Ellenbogen, MD##; Kevin M. Guskiewicz, PhD***; Stanley A. Herring, MD†††; Grant L. Iverson, PhD‡‡‡; Barry D. Jordan, MD§§§; James Kissick, MD||||||; Michael McCrea, PhD¶¶¶; Andrew S. McIntosh, PhD###; David Maddocks, LLB, PhD****; Michael Makdissi, MBBS, PhD††††; Laura Purcell, MD‡‡‡‡; Margot Putukian, MD§§§§; Kathryn Schneider, PhD||||||||; Charles H. Tator, MD, PhD¶¶¶¶; Michael Turner, MD####

The cumulative effect of repetitive concussion in sports

The increased popularity of contact sports world-wide exposes a large number of participants to both acute and chronic traumatic brain injury. Chronic traumatic brain injury (CTBI) represents the cumulative, long-term neurological consequences of repetitive concussive and subconcussive blows to the brain. Although this condition has been described primarily in boxing, it may be anticipated in other contact sports such as soccer, football, ice hockey, and the martial arts. Since treatment options in CTBI are relatively limited, the prevention of CTBI is of paramount importance. Minimizing the frequency and severity of acute brain injury in sport will be instrumental in accomplishing this goal. The prevention of CTBI will need to be sport specific and will undoubtedly rely on limiting the exposure of high-risk athletes, utilizing of protective equipment, enforcing strict rule adherence, training and supervising athletes, and increasing medical surveillance.

The clinical spectrum of sport-related traumatic brain injury

Acute and chronic sports-related traumatic brain injuries (TBIs) are a substantial public health concern. Various types of acute TBI can occur in sport, but detection and management of cerebral concussion is of greatest importance as mismanagement of this syndrome can lead to persistent or chronic postconcussion syndrome (CPCS) or diffuse cerebral swelling. Chronic TBI encompasses a spectrum of disorders that are associated with long-term consequences of brain injury, including chronic traumatic encephalopathy (CTE), dementia pugilistica, post-traumatic parkinsonism, post-traumatic dementia and CPCS. CTE is the prototype of chronic TBI, but can only be definitively diagnosed at autopsy as no reliable biomarkers of this disorder are available. Whether CTE shares neuropathological features with CPCS is unknown. Evidence suggests that participation in contact–collision sports may increase the risk of neurodegenerative disorders such as Alzheimer disease, but the data are conflicting. In this Review, the spectrum of acute and chronic sport-related TBI is discussed, highlighting how examination of athletes involved in high-impact sports has advanced our understanding of pathology of brain injury and enabled improvements in detection and diagnosis of sport-related TBI.

Lower Cognitive Performance of Older Football Players Possessing Apolipoprotein E ε4

OBJECTIVETo determine whether the cognitive status of professional football players varies as a function of age and apolipoprotein E (APOE) genotype. METHODSFifty-three active players underwent APOE and neuropsychological assessments. Players were grouped according to age (proxy indicator of high/low exposure to contact) and the presence/absence of at least one copy of the &egr;4 allele. Outcome measures were overall cognitive performance and scores in cognitive domains. RESULTSAs a group, older players possessing APOE &egr;4 exhibited significantly lower cognitive test scores than did all other players studied, including non-&egr;4-possessing players and younger &egr;4-carriers. Measures of general cognitive functioning, information-processing speed and accuracy, and attention were related to poorer performance among the &egr;4-carrying players. In an analysis of variance model, the interaction between APOE genotype and age was significant (P = 0.004). As determined using linear regression, age accounted for 34% of the variance in the memory index among APOE &egr;4-possessing players but did not contribute significantly to variance among the non-&egr;4-possessing players. Older APOE &egr;4-carriers were significantly overrepresented among players whose scores indicated possible cognitive impairment, with the criterion of performing two or more standard deviations below the general normal values in a summary index of general cognitive functioning. CONCLUSIONOlder professional football players who possessed the APOE &egr;4 allele scored lower on cognitive tests than did players without this allele or less experienced players of any genotype. The cognitive status of professional athletes with repeated exposure to head trauma may therefore be influenced by age, inherited factors such as APOE genotype, and cumulative exposure to contact.

Genetic Influences on Outcome Following Traumatic Brain Injury

Several genes have been implicated as influencing the outcome following traumatic brain injury (TBI). Currently the most extensively studied gene has been APOE. APOE can influence overall and rehabilitation outcome, coma recovery, risk of posttraumatic seizures, as well as cognitive and behavioral functions following TBI. Pathologically, APOE is associated with increased amyloid deposition, amyloid angiopathy, larger intracranial hematomas and more severe contusional injury. The proposed mechanism by which APOE affects the clinciopathological consequences of TBI is multifactorial and includes amyloid deposition, disruption of cytoskeletal stability, cholinergic dysfunction, oxidative stress, neuroprotection and central nervous system plasticity in response to injury. Other putative genes have been less extensively studied and require replication of the clinical findings. The COMT and DRD2 genes may influence dopamine dependent cognitive processes such as executive/frontal lobe functions. Inflammation which is a prominent component in the pathophysiological cascade initiated by TBI, is in part is mediated by the interleukin genes, while apoptosis that occurs as a consequence of TBI may be modulated by polymorphisms of the p53 gene. The ACE gene may affect TBI outcome via mechanisms of cerebral blood flow and/or autoregulation and the CACNA1A gene may exert an influence via the calcium channel and its effect on delayed cerebral edema. Although several potential genes that may influence outcome following TBI have been identified, future investigations are needed to validate these genetic studies and identify new genes that might influence outcome following TBI.

What is the evidence for chronic concussion-related changes in retired athletes: behavioural, pathological and clinical outcomes?

Objective The purpose of this paper was to review the current state of evidence for chronic traumatic encephalopathy (CTE) in retired athletes and to consider the potential differential diagnoses that require consideration when retired athletes present with cognitive and psychiatric problems. Data sources MEDLINE, CINAHL, EMBASE, Mosbys Index, PsycEXTRA, PsycINFO and Scopus. Key words included CTE, dementia pugilistica, punch drunk syndrome, traumatic encephalopathy, CTE, repetitive head injury, sports concussion, multiple concussions, chronic concussions, subconcussive blow and sports-related traumatic brain injury. Results At present, there are no published epidemiological, cross-sectional or prospective studies relating to modern CTE. Owing to the nature of the published studies, being case reports or pathological case series, it is not possible to determine the causality or risk factors with any certainty. As such, the speculation that repeated concussion or subconcussive impacts cause CTE remains unproven. The extent to which age-related changes, psychiatric or mental health illness, alcohol/drug use or coexisting dementing illnesses contribute to this process is largely unaccounted for in the published literature. Conclusions At present, the interpretation of causation in the modern CTE case studies should proceed cautiously. The causal assumptions require further prospective or longitudinal studies on the topic.

Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study

To investigate and localize cerebral abnormalities in professional boxers with no history of moderate or severe head trauma.