[Cerebral lesions of concussion and survival in a person suffering from concussion].
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Blast Injuries↗
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Decompression in percussion concussion: effects on "concussive response" in rabbits.
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Animals↗
[Specific difficulties principally affecting certain aspects of language following simple concussions in the child. Short- and long-term psychometric study of 20 cases of concussion in subjects between 4 and one-half and 11-years-old].
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Brain Concussion↗
Concussions among university football and soccer players.
OBJECTIVE: A study to examine the incidence and characteristics of concussions among Canadian university athletes during 1 full year of football and soccer participation. DESIGN: Retrospective survey. PARTICIPANTS: Three hundred eighty Canadian university football and 240 Canadian university soccer players reporting to 1999 fall training camp. Of these, 328 football and 201 soccer players returned a completed questionnaire. MAIN OUTCOME MEASURES: Based on self-reported symptoms, calculations were made to determine the number of concussions experienced during the previous full year of football or soccer participation, the duration of symptoms, the time for return to play, and any associated risk factors for concussions. RESULTS: Of all the athletes who returned completed questionnaires, 70.4% of the football players and 62.7% of the soccer players had experienced symptoms of a concussion during the previous year. Only 23.4% of the concussed football players and 19.8% of the concussed soccer players realized they had suffered a concussion. More than one concussion was experienced by 84.6% of the concussed football players and 81.7% of the concussed soccer players. Examining symptom duration, 27.6% of all concussed football players and 18.8% of all concussed soccer players experienced symptoms for at least 1 day or longer. Tight end and defensive lineman were the positions most commonly affected in football, while goalies were the players most commonly affected in soccer. Variables that increased the odds of suffering a concussion during the previous year for football players included a history of a traumatic loss of consciousness or a recognized concussion in the past. Variables that increased the odds of suffering a concussion during the previous year for soccer players included a past history of a recognized concussion while playing soccer and being female. CONCLUSIONS: University football and soccer players seem to be experiencing a significant amount of concussions while participating in their respective sports. Variables that seem to increase the odds of suffering a concussion during the previous year for football and soccer players include a history of a recognized concussion. Despite being relatively common, symptoms of concussion may not be recognized by many players.
Adult↗
Cumulative effects of concussion in high school athletes.
OBJECTIVE: A common assumption in sports medicine is that a history of concussion is predictive of a lower threshold for, as well as a worse outcome after, subsequent concussive injury. The current study was conducted to investigate the relationship between concussion history in high school athletes and the on-field presentation of symptoms after subsequent concussion. METHODS: One hundred seventy-three athletes who experienced sports-related concussion composed the initial study group. Binary groups were subsequently created on the basis of concussion history. Sixty athletes with no concussion history were compared with 28 athletes with a history of three or more concussions. The groups were compared in terms of the on-field presentation of symptoms after an in-study concussion. Dependent variables included the postinjury presence of loss of consciousness, anterograde amnesia, retrograde amnesia, and confusion. RESULTS: Athletes with three or more prior concussions were more likely to experience on-field positive loss of consciousness (chi(2) = 8.0, P = 0.005), anterograde amnesia (chi(2) = 5.5, P = 0.019), and confusion (chi(2) = 5.1, P = 0.024) after a subsequent cerebral concussion. An odds ratio revealed that athletes with a history of three concussions were 9.3 times more likely than athletes with no history of concussion to demonstrate three to four abnormal on-field markers of concussion severity. CONCLUSION: This study is the first to suggest a cumulative effect of concussion in high school athletes. A more severe on-field presentation of concussion markers is evidenced in high school athletes with a pronounced history of concussion. This study's findings highlight the need for more long-term outcome studies in high school athletes who sustain sports-related concussions.
Adolescent↗
Concussions among university football and soccer players: a pilot study.
OBJECTIVE: A pilot study to examine the incidence and characteristics of concussions for one season of university football and soccer. DESIGN: Retrospective survey. PARTICIPANTS: 60 football and 70 soccer players reporting to 1998 fall training camp. Of these, 44 football and 52 soccer players returned a completed questionnaire. MAIN OUTCOME MEASURES: Based on self-reported symptoms, calculations were made to determine the number of concussions experienced during the previous season, the duration of symptoms, the time for return to play and any associated risk factors for concussions. RESULTS: Of all the athletes who returned completed questionnaires, 34.1% of the football players and 46.2% of the soccer players had experienced symptoms of a concussion during the previous season. Only 16.7% of the concussed football players and 29.2% of the concussed soccer players realized they had suffered a concussion. All of the concussed football players and 75.0% of the concussed soccer players experienced more than one concussion during the season. The symptoms from the concussion lasted for at least 1 day in 28.6% of the football players and 18.1% of the soccer players. Variables that increased the odds of suffering a concussion during the previous season for football and soccer players included a past history of a recognized concussion. CONCLUSION: More university soccer players than football players may be experiencing sport related concussions. Variables that seem to increase the odds of suffering a concussion during the previous season for football and soccer players include a history of a recognized concussion. Despite being relatively common, many players may not recognize the symptoms of a concussion.
Adult↗
Unreported concussion in high school football players: implications for prevention.
OBJECTIVE: To investigate the frequency of unreported concussion and estimate more accurately the overall rate of concussion in high school football players. DESIGN: Retrospective, confidential survey completed by all subjects at the end of the football season. SETTING AND PARTICIPANTS: A total of 1,532 varsity football players from 20 high schools in the Milwaukee, Wisconsin, area were surveyed. MAIN OUTCOME MEASUREMENTS: The structured survey assessed (1) number of concussions before the current season, (2) number of concussions sustained during the current season, (3) whether concussion during the current season was reported, (4) to whom concussion was reported, and (5) reasons for not reporting concussion. RESULTS: Of respondents, 29.9% reported a previous history of concussion, and 15.3% reported sustaining a concussion during the current football season; of those, 47.3% reported their injury. Concussions were reported most frequently to a certified athletic trainer (76.7% of reported injuries). The most common reasons for concussion not being reported included a player not thinking the injury was serious enough to warrant medical attention (66.4% of unreported injuries), motivation not to be withheld from competition (41.0%), and lack of awareness of probable concussion (36.1%). CONCLUSIONS: These findings reflect a higher prevalence of concussion in high school football players than previously reported in the literature. The ultimate concern associated with unreported concussion is an athlete's increased risk of cumulative or catastrophic effects from recurrent injury. Future prevention initiatives should focus on education to improve athlete awareness of the signs of concussion and potential risks of unreported injury.
Adolescent↗
Concussion among Swedish elite ice hockey players.
OBJECTIVE: To evaluate the frequency of concussion in Swedish ice hockey and to establish a uniform grading and treatment model for concussions of different severity. METHODS: Frequency of concussion was investigated in two studies, one retrospective and one prospective. In the retrospective study, all Swedish elite ice hockey players (n = 265) were asked to answer a questionnaire on the number and treatment of previous concussions. Only concussions diagnosed by a doctor were recorded. The questionnaire was completed by 227 players (86%). In the prospective study, all injuries including concussions occurring during game and practice in the Swedish Elite League (n = 12 teams) were recorded during four years. The causes of injury, referees judgements, diagnosis, treatment, and time absent from ice hockey were registered on special cards. RESULTS: In the retrospective study, 51 out of 227 players (22%) in the Swedish Elite League reported at least one concussion. In the prospective study, 52 concussions were reported. The incidence of a concussion is at least one concussion every year/team or a yearly risk of about 5% for a player to sustain a concussion. Most concussions occurred during league play (81%). Body contact (checking or boarding) was the most common cause of concussions. The players were absent from full training and play on a mean of 6 d. CONCLUSIONS: As this injury is potentially dangerous it must be treated seriously according to a simple treatment model presented. In cases of repeated concussions during the same season, a longer period of time away from play is suggested. In players who have sustained several concussions over the years a thorough medical examination including EEG, CT/MRI, and neuropsychological tests should be performed. If any of these is pathological the player should be advised to give up ice hockey.
Absenteeism↗
Enduring effects of concussion in youth athletes.
The purpose of this study was to explore the mild, enduring effects of concussion in otherwise healthy youth athletes. Reported history of concussion and cognitive functioning was examined in an initial sample of 35 youth athletes, 21 of whom were considered healthy volunteers (No Recent Concussion within the past 6 months) with no identified medical or neuropsychological difficulties related to concussion. The remaining 14 volunteers had each sustained a concussion within 1 week of testing (Recent Concussion). Significant differences in performances on a general cognitive measure, and specifically in the area of attention, were found as a function of number of concussions reported by the No Recent Concussion athletes. Furthermore, on some of the measures, No Recent Concussion athletes with a history of two or more concussions appeared to resemble Recent Concussion athletes more so than No Recent Concussion athletes with a history of one or no concussion. The importance of assessment of youth concussion and the use of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) for this purpose are discussed.
Journal Article↗
Concussions during the 1997 Canadian Football League season.
OBJECTIVE: To examine the incidence and characteristics of concussions for one season in the Canadian Football League (CFL). DESIGN: Retrospective survey. PARTICIPANTS: 289 players reporting to CFL training camp. Of these, 154 players had played in the CFL during the 1997 season. MAIN OUTCOME MEASURES: Based on self-reported symptoms, calculations were made to determine the number of concussions experienced during the previous season, the duration of symptoms, the time for return to play after concussion, and any associated risk factors for concussions. RESULTS: Of all the athletes who played during the 1997 season, 44.8% experienced symptoms of a concussion. Only 18.8% of these concussed players recognized they had suffered a concussion. 69.6% of all concussed players experienced more than one episode. Symptoms lasted at least 1 day in 25.8% of cases. The odds of experiencing a concussion increased 13% with each game played. A past history of a loss of consciousness while playing football and a recognized concussion while playing football were both associated with increased odds of experiencing a concussion during the 1997 season. CONCLUSION: Many players experienced a concussion during the 1997 CFL season, but the majority of these players may not have recognized that fact. Players need to be better informed about the symptoms and effects of concussions.
Adult↗
Temporal window of vulnerability to repetitive experimental concussive brain injury.
OBJECTIVE: Repetitive concussive brain injury (CBI) is associated with cognitive alterations and increased risk of neurodegenerative disease. METHODS: To evaluate the temporal window during which the concussed brain remains vulnerable to a second concussion, anesthetized mice were subjected to either sham injury or single or repetitive CBI (either 3, 5, or 7 days apart) using a clinically relevant model of CBI. Cognitive, vestibular, and sensorimotor function (balance and coordination) were evaluated, and postmortem histological analyses were performed to detect neuronal degeneration, cytoskeletal proteolysis, and axonal injury. RESULTS: No cognitive deficits were observed in sham-injured animals or those concussed once. Mice subjected to a second concussion within 3 or 5 days exhibited significantly impaired cognitive function compared with either sham-injured animals (P < 0.05) or mice receiving a single concussion (P < 0.01). No cognitive deficits were observed when the interconcussion interval was extended to 7 days, suggestive of a transient vulnerability of the brain during the first 5 days after an initial concussion. Although all concussed mice showed transient motor deficits, vestibulomotor dysfunction was more pronounced in the group that sustained two concussions 3 days apart (P < 0.01 compared with all other groups). Although scattered degenerating neurons, evidence of cytoskeletal damage, and axonal injury were detected in selective brain regions between 72 hours and 1 week after injury in all animals sustaining a single concussion, the occurrence of a second concussion 3 days later resulted in significantly greater traumatic axonal injury (P < 0.05) than that resulting from a single CBI. CONCLUSION: These data suggest that a single concussion is associated with behavioral dysfunction and subcellular alterations that may contribute to a transiently vulnerable state during which a second concussion within 3 to 5 days can lead to exacerbated and more prolonged axonal damage and greater behavioral dysfunction.
Animals↗
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.
Adolescent↗
Relationship between concussion and neuropsychological performance in college football players.
CONTEXT: Despite the high prevalence and potentially serious outcomes associated with concussion in athletes, there is little systematic research examining risk factors and short- and long-term outcomes. OBJECTIVES: To assess the relationship between concussion history and learning disability (LD) and the association of these variables with neuropsychological performance and to evaluate postconcussion recovery in a sample of college football players. DESIGN, SETTING, AND PARTICIPANTS: A total of 393 athletes from 4 university football programs across the United States received preseason baseline evaluations between May 1997 and February 1999. Subjects who had subsequent football-related acute concussions (n = 16) underwent neuropsychological comparison with matched control athletes from within the sample (n = 10). MAIN OUTCOME MEASURES: Clinical interview, 8 neuropsychological measures, and concussion symptom scale ratings at baseline and after concussion. RESULTS: Of the 393 players, 129 (34%) had experienced 1 previous concussion and 79 (20%) had experienced 2 or more concussions. Multivariate analysis of variance yielded significant main effects for both LD (P<.001) and concussion history (P=.009), resulting in lowered baseline neuropsychological performance. A significant interaction was found between LD and history of multiple concussions and LD on 2 neuropsychological measures (Trail-Making Test, Form B [P=.007] and Symbol Digit Modalities Test [P=.009]), indicating poorer performance for the group with LD and multiple concussions compared with other groups. A discriminant function analysis using neuropsychological testing of athletes 24 hours after acute in-season concussion compared with controls resulted in an overall 89.5% correct classification rate. CONCLUSIONS: Our study suggests that neuropsychological assessment is a useful indicator of cognitive functioning in athletes and that both history of multiple concussions and LD are associated with reduced cognitive performance. These variables may be detrimentally synergistic and should receive further study.
Adolescent↗
The neurophysiology of concussion.
Cerebral concussion is both the most common and most puzzling type of traumatic brain injury (TBI). It is normally produced by acceleration (or deceleration) of the head and is characterized by a sudden brief impairment of consciousness, paralysis of reflex activity and loss of memory. It has long been acknowledged that one of the most worthwhile techniques for studying the acute pathophysiology of concussion is by the recording of neurophysiological activity such as the electroencephalogram (EEG) and sensory evoked potentials (EPs) from experimental animals. In the first parts of this review, the majority of such studies conducted during the past half century are critically reviewed. When potential methodological flaws and limitations such as anesthetic protocols, infliction of multiple blows and delay in onset of recordings were taken into account, two general principles could be adduced. First, the immediate post-concussive EEG was excitatory or epileptiform in nature. Second, the cortical EP waveform was totally lost during this period. In the second parts of this review, five theories of concussion which have been prominent during the past century are summarized and supportive evidence assessed. These are the vascular, reticular, centripetal, pontine cholinergic and convulsive hypotheses. It is concluded that only the convulsive theory is readily compatible with the neurophysiological data and can provide a totally viable explanation for concussion. The chief tenet of the convulsive theory is that since the symptoms of concussion bear a strong resemblance to those of a generalized epileptic seizure, then it is a reasonable assumption that similar pathobiological processes underlie them both. Further, it is demonstrated that EPs and EEGs recorded acutely following concussive trauma are indeed the same or similar to those obtained following the induction of a state of generalized seizure activity (GSA). According to the present incarnation of the convulsive theory, the energy imparted to the brain by the sudden mechanical loading of the head may generate turbulent rotatory and other movements of the cerebral hemispheres and so increase the chances of a tissue-deforming collision or impact between the cortex and the boney walls of the skull. In this conception, loss of consciousness is not orchestrated by disruption or interference with the function of the brainstem reticular activating system. Rather, it is due to functional deafferentation of the cortex as a consequence of diffuse mechanically-induced depolarization and synchronized discharge of cortical neurons. A convulsive theory can also explain traumatic amnesia, autonomic disturbances and the miscellaneous collection of symptoms of the post-concussion syndrome more adequately than any of its rivals. In addition, the symptoms of minor concussion (a.k.a. being stunned, dinged, or dazed) are often strikingly similar to minor epilepsy such as petit mal. The relevance of the convulsive theory to a number of associated problems is also discussed. These include the relationship between concussion and more serious types of closed head injury, the utility of animal models of severe brain trauma, the etiology of the cognitive deficits which may linger long after a concussive injury, the use of concussive (captive bolt) techniques to stun farm animals prior to slaughter and the question of why some animals (such as the woodpecker) can tolerate massive accelerative forces without being knocked out.
Animals↗
Concussion in professional football: repeat injuries--part 4.
OBJECTIVE: A 6-year study was conducted to determine the signs, symptoms, and management of repeat concussion in National Football League players. METHODS: From 1996 to 2001, concussions were reported by 30 National Football League teams using a standardized reporting form filled out by team physicians with input from athletic trainers. Signs and symptoms were grouped by general symptoms, somatic complaints, cranial nerve effects, cognition problems, memory problems, and unconsciousness. Medical actions taken and management were recorded. RESULTS: Data were captured for 887 concussions in practices and games involving 650 players. A total of 160 players experienced repeat injury, with 51 having three or more concussions during the study period. The median time between injuries was 374.5 days, with only six concussions occurring within 2 weeks of the initial injury. Repeat concussions were more prevalent in the secondary (16.9%), the kick unit on special teams (16.3%), and wide receivers (12.5%). The ball return carrier on special teams (odds ratio [OR] = 2.08, P = not significant) and quarterbacks (OR = 1.92, P < 0.1) had elevated odds for repeat injury, followed by the tight end (OR = 1.24, P = not significant) and linebackers (OR = 1.22, P = not significant). There were similar signs and symptoms with single and repeat concussion, except for a higher prevalence of somatic complaints in players on their repeat concussions compared with their first concussion (27.5% versus 18.8%, P < 0.05). More than 90% of players were managed by rest, and 57.5% of those with second injuries returned to play within a day. Players with three or more concussions had signs, symptoms, and treatment similar to those with only a single injury. CONCLUSION: The most vulnerable players for repeat concussion in professional football are the ball return carrier on special teams and quarterbacks. Single and repeat concussions are managed conservatively with rest, and most players return quickly to play.
Athletic Injuries↗
[Early pathophysiological findings in experimental concussion in rabbits].
Early neurophysiological changes and pathological findings were studied following experimental cerebral concussion in rabbits. The animals were lightly anesthetized and subjected to occipital trauma with a pendulum impactor. Experimental concussion was defined as fulfillment of at least two of the three following criteria: apnea for more than 10 seconds, absence of the light reflex for more than 10 seconds, and bradycardia or tachycardia (less than 50% or more than 10% of the preimpact rate, respectively). There were 13 cases of lethal concussion, 16 of nonlethal concussion, and 15 of nonconcussion. The resultant head acceleration ranged from 250 to 1660 G and its duration was 0.8 to 5.5 msec. During the first 30 seconds after impact, electroencephalographic activity showed little change even in cases of lethal concussion, but slowed over the next several minutes due to respiratory suppression. The duration of apnea in cases of nonconcussion was under 9 seconds and, in cases of nonlethal concussion, averaged 21 seconds. Five of the rabbits with lethal concussion were apneic throughout the observation period, and the remaining eight exhibited apnea for an average of 46 seconds after impact. The light reflex was absent for less than 9 seconds in nonconcussion cases and for an average of 71 seconds in cases of nonlethal concussion. One animal with lethal concussion exhibited absence of the light reflex throughout, and the remaining 12 animals for an average of 39 seconds. Bradycardia was seen in 15 cases of nonlethal and two cases of lethal concussion. Six rabbits with lethal concussion had tachycardia. Two animals without concussion showed bradycardia and the remainder showed no change.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Cumulative effects of concussion in amateur athletes.
PRIMARY OBJECTIVE: To examine the possibility that athletes with multiple concussions show cumulative effects of injury. METHODS AND PROCEDURES: Amateur athletes with a history of three or more concussions were carefully matched (gender, age, education and sport) with athletes with no prior concussions. All completed a computerized neuropsychological test battery at preseason (ImPACT) and then within 5 days of sustaining a concussion (mean = 1.7 days). MAIN OUTCOMES AND RESULTS: There were differences between groups in symptom reporting and memory performance. At baseline (i.e. preseason), athletes with multiple concussions reported more symptoms than athletes with no history of concussion. At approximately 2 days post-injury, athletes with multiple concussions scored significantly lower on memory testing than athletes with a single concussion. Athletes with multiple concussions were 7.7 times more likely to demonstrate a major drop in memory perfomance than athletes with no previous concussions. CONCLUSIONS: This study provides preliminary evidence to suggest that athletes with multiple concussions might have cumulative effects.
Adolescent↗
Sensitivity and specificity of the ImPACT Test Battery for concussion in athletes.
This study explored the diagnostic utility of the composite scores of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) and Post Concussion Symptom Scale scores (PCSS). Recently concussed high school athletes (N=72) were tested within 72 h of sustaining a concussion, and data were compared to non-concussed high school athletes with no history of concussion (N=66). Between-groups MANOVA revealed a significant multivariate effect of concussion on test performance (p<.001); univariate ANOVAS revealed all six measures contributed to the between-groups differences. A discriminant function analyses was conducted to measure the ability of the five ImPACT composite scores, as well as the PCSS to classify concussion status. One discriminant function was identified that consisted of the Visual Memory, Processing Speed, and Impulse Control composite scores PCSS, which correctly classified 85.5% of the cases. Approximately 82% of participants in the concussion group and 89% of participants in the control group were correctly classified. Using these data, the sensitivity of ImPACT was 81.9%, and the specificity was 89.4%. As part of a formal concussion management program, ImPACT is a useful tool for the assessment of the neurocognitive and neurobehavioral sequelae of concussion, and can also provide post-injury cognitive and symptom data that can assist a practitioner in making safer return to play decisions.
Adolescent↗