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Cumulative effects of concussion in amateur athletes


Abstract and Figures

To examine the possibility that athletes with multiple concussions show cumulative effects of injury. 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). 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. This study provides preliminary evidence to suggest that athletes with multiple concussions might have cumulative effects.
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BRAIN INJURY, VOL. 18, NO.5(MAY 2004), 433443
Cumulative effects of concussion in
amateur athletes
yUniversity of British Columbia, Vancouver, BC, Canada
zUniversity of Pittsburgh Medical Center, Pittsburgh, PA, USA
(Received 17 December 2003; accepted 20 June 2003)
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 ¼ 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
performance than athletes with no previous concussions.
Conclusions: This study provides preliminary evidence to suggest that athletes with multiple concussions
might have cumulative effects.
Children and adolescents frequently experience concussion in sports or other physi-
cal activities. Of particular concern is competition at the high school level, where
at least 1.25 million athletes compete in contact sports. An estimated 62 816 cases
of concussion occur annually at the high school level, with American football
accounting for about 63% of cases [1]. It is well known that many people who
sustain concussions experience post-concussion symptoms and decrements on neuro-
psychological testing during the first week post-injury [2–5]. Fortunately, the vast
majority of people who sustain a single concussion recover relatively quickly and
fully. Recovery has been demonstrated in trauma patients [5, 6], athletes [4],
children [7], and the elderly [8,9]. Although the vast majority of people who
sustain concussions eventually recover, concussions can be significant injuries that
Brain Injury ISSN 0269–9052 print/ISSN 1362–301X online # 2004 Taylor & Francis Ltd
DOI: 10.1080/02699050310001617352
Correspondence to: Grant Iverson, PhD, Department of Psychiatry, 2255 Wesbrook Mall,
University of British Columbia, Vancouver, BC, Canada V6T 2B4. e-mail: giverson@interchange.
result in distressing symptoms and clear declines in measured cognitive abilities.
Concussions should not be dismissed lightly, and young people with ongoing
symptoms (e.g. headaches or feeling ‘foggy’) should be managed conservatively.
Unfortunately, there is very little research on concussions in high school athletes.
This lack of research is alarming for several reasons. First, based on participation
levels, the largest group of at-risk athletes is at the high school level or below.
Second, at least 17 deaths related to second impact syndrome (which results from
a second concussive insult closely following the first) were reported in the literature
between 1992 and 1997 [10], and periodic cases continue to be reported. The
majority of victims have been high school athletes between the ages of 13 and
18 years, suggesting the possibility of greater vulnerability to severe injury in
children and adolescents versus adults. However, this vulnerability has yet to be
established empirically. It is important to be aware of second impact syndrome,
while keeping in mind that it is an extremely rare phenomenon. The vast majority
of amateur athletes who sustain light concussions recover quickly and fully, typically
within 3–10 days [4, 11–13].
In sport, the risk for long-term problems is rarely, if ever, associated with a single
concussion. Rather, long-term problems are believed to be associated with multiple
concussions. Awareness of the detrimental effects of repetitive concussions has
existed in modern-era sports medicine for decades both anecdotally and in the
clinical literature. Early examples from boxing include Martland’s [14] work on
dementia pugilistica (punch-drunk syndrome) and later chronic [15] and traumatic
boxer’s encephalopathy [16]. More recently, concussion in sport, and the aftermath
of multiple concussions, has been witnessed by the masses as numerous professional
athletes have had their careers prematurely ended due to these injuries.
Sports involving impact to the head such as American football, boxing and ice
hockey provide an opportunity to explore the effects of multiple concussions.
Peerless and Rewcastle [17] noted that boxers appear to make a rapid and full
recovery from a single slight concussion, but after repeated episodes, there is a
gradual appearance of permanent sequelae. The risk of sustaining a concussion in
American football has been reported to be four-to-six times greater if the player has
already sustained a concussion [18]. Permanent brain injuries due to multiple
concussions have been reported in ice hockey players [19]. In a study employing
neuropsychological testing, researchers suggested that cumulative effects of concus-
sion might be detectable in amateur soccer (i.e. Association football) players [20];
however, other researchers have reported no adverse effects associated with partic-
ipation in competitive soccer [21]. In a large study involving college American
football players, athletes with a history of two or more concussions reported
more preseason (i.e. baseline) symptoms, and they performed more poorly on
two tests designed to measure information processing speed than athletes with no
previous concussions [11]. In the most frequently cited study, Gronwall and
Wrightson [22] reported that trauma patients, some with multiple concussions,
scored significantly lower on an auditory processing task than patients with only
one concussion. In addition, a recent study demonstrated statistical differences in
post-concussion symptoms and cognitive event-related potentials at baseline for
young amateur hockey players with zero versus three or more concussions [23].
Animal models of neurotrauma suggest that limited but significant damage to
neurons can result from a single concussion (although the animal research typically
involved much more serious traumatic brain injuries than the concussions sustained
434 G. L. Iverson et al.
in sports). The notion of a continuum of injury [17, 24] implies that as acceleration/
deceleration forces increase, the number of cells damaged will increase and that
damage will progressively occur in deeper structures. Gennarelli [25] described
a continuum of injury with four stages based on increasingly severe strains on
nodal and paranodal regions of axons. Stage 2 damage (axonal ‘stretch’ from 5 to
10%) resulted primarily in transient cellular dysfunction and marked the initiation of
limited cell death.
Different types of neurons appear to be susceptible to acceleration/deceleration
forces, that are largely dependent on the amount of force and the direction of
movement of the head. In addition, neurons may be differentially susceptible to
acceleration/deceleration forces. For instance, when axons change direction to
accommodate the presence of a blood vessel, enter target nuclei (e.g. the grey/
white interface), decussate, or are of large calibre, they may be more susceptible to
injury [26–29]. Although researchers who employ animal models have demon-
strated the effects of single injuries on subsequent brain functions and structure,
little evidence is available on the effects of multiple concussions. Early studies
employing animal models designed to contrast repetitive versus single impact of
concussive and subconcussive injuries suggested that after a single subconcussive
impact, no change was observed in animal behaviour or histology. In contrast,
repetitive subconcussive episodes between 5 and 20-s intervals often resulted in
permanent injury [30, 31]. Obviously, it is very difficult to extrapolate from animal
research to concussions sustained by humans in sport. Nonetheless, a basic science
foundation for possible cumulative effects is apparent.
The purpose of this study was to replicate and extend the results of previous
studies that reported increased post-concussion symptoms at baseline for amateur
athletes who sustained multiple concussions versus those who had not sustained
a concussion. In addition, the severity of on-field markers and symptoms following
a subsequent concussion were examined to determine whether athletes with a history
of multiple concussions experience more severe symptoms and greater measured
neuropsychological decrements than athletes with no prior concussions.
All subjects participated in the University of Pittsburgh Medical Center Sports
Concussion Program. The programme uses preseason and post-injury neuropsycho-
logical testing protocols to help determine return to play in athletes sustaining
concussions. Immediate Post Concussion Assessment and Cognitive Testing
(ImPACT), a computer-based demographic, symptom and neuropsychological
test program, was used at baseline and at each post-concussion follow-up assessment.
Amateur athletes with three or more concussions were selected from a large
database of players who took part in the programme. Only subjects with complete
data at baseline and at 1–2 day follow-up were included. A sample of 19 athletes,
11 high school and eight college, were identified. A sample of athletes who were
matched on age, education, level (high school or college), gender, sport, and days
post-injury was then carefully selected. The results of this matching are presented in
table 1. Therefore, the total sample consisted of 38 players, 19 with a history of
three or more concussions and 19 with no prior concussions. Because of the careful
Cumulative effects of concussion in amateur athletes 435
matching, there obviously were no statistically significant differences between
groups on the demographic variables.
ImPACT is a computer-administered neuropsychological test battery that consists of
seven individual test modules that measure aspects of cognitive functioning includ-
ing attention, memory, reaction time and processing speed. It also contains a post-
concussion symptom scale.
The memory index is comprised of five subtest scores measuring different aspects
of memory including verbal (word) learning and recognition memory, visual associa-
tive memory, visual working memory, and letter memory. This composite index
represents the average per cent correct score for these five scores. The test battery
is designed to minimize practise effects by randomizing the stimuli. With the excep-
tion of the recognition word memory test, presentation of all stimuli is varied auto-
matically for each examination. For example, for each administration of the symbol
match, three letter memory, and visual memory tasks (X’s and O’s), the computer
automatically randomizes the stimuli presented to minimize memorization of the
presented sequences across multiple evaluations. The word memory module has five
separate forms. To make up the five word lists, the words were randomly selected
from a group of single syllable nouns. In addition to the 12 target words, each word is
paired with a similar but not identical word (e.g. ‘snow or ice’, ‘doctor or nurse’).
Table 1. Demographic information, preseason testing, post-concussion testing, and on-field injury severity
markers by group
Variable No previous concussions Three or more concussions
Age (years) 17.9 (median ¼ 17, SD ¼ 2.7) 17.8 (17, 2.5)
Education-years 11.8 (median ¼ 11, SD ¼ 2.5) 11.9 (11, 2.5)
Gender 18 male 17 male
Education level 11 high school, 8 college 12 high school, 7 college
Sport 15 American football,
3 football, 1 baseball
14 American football, 2 football,
2 basketball, 1 lacrosse
Days post-injury 1.8 (median ¼ 1, SD ¼ 1.3) 1.6 (1, 1.5)
Number of athletes 19 19
Subjective symptoms 5.6 (SD ¼ 8.1) 14.1 (15.8)
Reaction time 0.57 (SD ¼ 0.09) 0.55 (0.06)
Processing speed 35.7 (SD ¼ 8.1) 34.4 (10.1)
Memory 89.1 (SD ¼ 6.5) 84.7 (12.0)
Subjective symptoms 21.5 (SD ¼ 23.4) 31.3 (26.4)
Reaction time 0.57 (SD ¼ 0.11) 0.56 (0.10)
Processing speed 36.6 (SD ¼ 8.0) 35.6 (7.8)
Memory 84.7 (SD ¼ 12.0) 74.5 (12.7)
On-field markers
Loss of consciousness 0 2
Retrograde amnesia 3 3
Post-traumatic amnesia 1 7
Disorientation 5 12
Five or more min of
mental status change
436 G. L. Iverson et al.
The module yields per cent correct recognition scores for both learning (per cent
correct recognition after two presentations) and delayed recognition (per cent correct
recognition approximately 15 min after the initial presentation).
The reaction time index represents the average time (s) to respond. All stimuli
are randomized to minimize practise effects. Three scores are used in the calculation
of the composite index. First, the distractor task for the X’s and O’s test module
(choice reaction time) requires the athlete to mouse click the left button if a blue
square appears on the screen and alternatively to right mouse click if a red circle
appears. The second score is the average correct reaction time score from the
colour-match module. For this test module, the athlete is presented with three
words (red, green, or blue) presented either in the same colour ink of the work
(e.g. the word ‘blue’ presented in blue ink) or in a different colour ink (‘red’ in
blue or green ink). Therefore, this task requires the athlete to respond rapidly while
inhibiting the impulse to respond to non-target words. Third, the average correct
reaction time score from the symbol match module consists of the average time to
respond to this task, which requires the athlete to mouse click on a given number,
when a specific symbol appears on the screen. The average correct reaction time is
divided by three to produce a score proportional to the other two scores. This final
score represents the reaction time composite index.
The visual–motor speed composite index consists of the average of two scores.
First the total number of blue squares or red circles correctly clicked during the
previously described X’s and O’s distractor task is divided by four. Second, the
distractor task from the three letters module is calculated and multiplied by three.
The three-letters module is a verbal working memory test that measures the ability
of the athlete to remember a series of three consonants that are immediately
followed by a distractor task that requires the athlete to click a randomly displayed
array of numbers in backward order from 25 to one. Therefore, the distractor task
provides a measure of visual search and visual–motor speed. The weighting of the
two scores that make up the visual processing composite index produces results in
a similar numeric range for both scores.
The post-concussion symptom scale has 21 symptoms (graded 0–6 in terms of
severity) commonly associated with concussion (e.g. headache, photosensitivity,
feeling slow, etc.). This scale was originally developed for use with the Pittsburgh
Steelers (a professional American football team) and is now used throughout profes-
sional and amateur sports [32, 33]. The athlete is asked to choose (via a mouse click)
the point on the scale that most accurately reflects his/her status with regard to each
symptom at that time.
Athletes underwent a baseline evaluation and were administered the computerized
test battery before the 2000 and 2001 athletic seasons. ImPACT consists of a
detailed symptom and demographic questionnaire (e.g. relevant sport/medical/
concussion history information), as well as seven individual test modules that mea-
sure aspects of cognitive functioning.
A standardized concussion history questionnaire contained within the ImPACT
test battery was administered with the supervision of the test administrator. Before
athletes completing this section, test administrators communicated to them that they
were to document each prior episode of cerebral concussion that was formally
Cumulative effects of concussion in amateur athletes 437
diagnosed by a team physician or certified athletic trainer. Athletes also documented
any prior concussion that resulted in loss of playing time. Test administrators were
trained to define concussion as a ‘traumatically induced alteration in mental status
that may or may not be accompanied by a loss of consciousness’. Non sports-related
concussions were also included in the tally only if diagnosed by a physician. Based
on these criteria, athletes, under the supervision of the test administrator, entered in
the total number of concussions experienced in their history.
Administration of the computerized neuropsychological test battery was super-
vised by a team of clinical neuropsychologists, certified athletic trainers, or physi-
cians who were thoroughly trained in the administration of the measures. Given
that ImPACT is a self-administered test battery, all information is gathered in a
standardized manner.
All athletes were re-administered the computerized battery within 5 days of
injury (mean ¼ 1.7 days). In-study concussions were characterized by the on-field
presentation of one or more of the following symptoms after a blow to the head
or body: (1) any observable alteration in mental status or consciousness; (2) a con-
stellation of self-reported symptoms, such as post-traumatic headache, ‘fogginess’,
nausea/vomiting, dizziness, etc.; and/or (3) the presence of loss of consciousness,
disorientation, post-traumatic amnesia (PTA) or retrograde amnesia (RTA) as iden-
tified by on-field examination. Sports medicine practitioners present on the sideline
at the time of injury made the diagnosis of concussion.
Sports medicine practitioners carefully documented information pertaining to
markers of injury severity. On-field disorientation was assessed by questioning the
athlete’s post-injury awareness and orientation to surroundings (e.g. name the cur-
rent stadium, city, opposing team, current month/day). On-field PTA was assessed
through immediate and delayed (e.g. 0, 5, 15 min) memory for three words (e.g.
girl, dog, green). PTA was further documented at the post-injury follow-up eval-
uation by assessing the athlete’s ability to recall all information after trauma. Any
loss of memory in this latter regard indicated positive presence of PTA. On-field
retrograde amnesia was assessed by having the athlete recall events that occurring
just before their injury (e.g. events in the first quarter, memory for play preceding
trauma, score of the game). Retrograde amnesia was further documented at the
post-injury evaluation by assessing the athlete’s ability to recall information just
before trauma. Any loss of memory in this latter regard indicated positive presence
of retrograde amnesia. Loss of consciousness was documented when an athlete was
unresponsive to external stimuli as documented by on-field evaluation by team
medical personnel. By definition, athletes experiencing loss of consciousness
(LOC) also experienced a concomitant PTA. For the purposes of the present
study, athletes with any degree of LOC were categorized in the positive LOC
group rather than the PTA or retrograde amnesia group.
A mixed-model 2 2 ANOVA was used to determine if there were between- and
within-group effects on each of the dependent variables (i.e. total symptoms, reac-
tion time, processing speed, and memory). For the total symptoms score, there was
a significant main effect for time; F(1, 36) ¼ 29.4, p < 0.00001, "
¼ 0.45. This is a
large effect size; approximately 45% of the variability in symptom scores was related
to the differences in performance across the two time intervals. There was not a
438 G. L. Iverson et al.
statistically significant group effect, although the observed power in this analysis was
very low (i.e. 0.35). In other words, there was only a 35% chance of correctly
rejecting a false null hypothesis. However, exploratory independent t-tests revealed
a significant difference between groups at preseason, with the athletes who had
multiple concussions reporting more symptoms ( p < 0.05, observed power ¼ 0.53,
d ¼ 0.71, large effect). The groups did not differ in total symptoms during the
post-injury follow-up assessment ( p ¼ 0.24; observed power ¼ 0.22, d ¼ 0.39,
small–medium effect). Again, however, low power could have affected this finding.
There was a trend toward an effect (table 1 and figure 1) and as demonstrated in the
effect size of 0.39. Specifically, the two groups differed by more than one-third of a
pooled standard deviation unit.
For the reaction time and processing speed composite scores, there were no
significant between- or within-group effects. Moreover, exploratory analyses
revealed no trends toward differences between groups.
For the memory composite score, there was a significant main effect for time;
F(1, 36) ¼ 13.1, p ¼ 0.001, "
¼ 0.27. This is a medium-to-large effect size; approxi-
mately 27% of the variability in memory scores was related to the differences in
performance across the two time intervals. There was also a group effect, with the
multiply concussed athletes showing greater decrements in memory functioning
than the mildly concussed subjects (F(1, 36) ¼ 7.0; p ¼ 0.012, "
¼ 0.16, observed
power ¼ 0.73). There was a clear trend toward lower memory performance in
the multiply concussed group at preseason ( p ¼ 0.08, two-tailed test, observed
power ¼ 0.42, d ¼ 0.59, medium effect size). These results are presented in table 1
and figure 2. If the effect size between groups remained constant and the
sample size in each group was increased from 19 to 25, then the two-tailed
p would be 0.04. The athletes with multiple concussions obtained significantly
lower memory composite scores during the post-injury assessment ( p ¼ 0.015,
observed power ¼ 0.70, d ¼ 0.83, large effect).
A 14-point drop in memory performance represents a major decline in function
between preseason and immediate follow-up (i.e. greater than 1.5 pooled SD
decline in performance). The 38 subjects were divided into two groups based
on whether they demonstrated this major decline in memory performance
Baseline 1-2 Days Post Injury
No Concussions Multiple Concussions
Figure 1. ImPACT symptom scores for the two groups.
Cumulative effects of concussion in amateur athletes 439
(i.e. 11 subjects demonstrated a major decline). A significantly greater proportion of
the athletes with multiple concussions (47.4%) versus no previous concussions
(10.5%) demonstrated a major decline in memory performance,
(1, 38) ¼ 6.3,
p < 0.013. The athletes with multiple concussions were 7.7 times more likely to
demonstrate a major drop in memory performance than the athletes with no
previous concussions (95% CI ¼ 1.442.7).
In terms of on-field markers, the groups did not differ in their experience of
LOC, retrograde amnesia or disorientation (table 1). Importantly, there was very low
power in all of these
analyses due to small sample sizes and some missing data.
There was a prominent trend toward a difference in post-traumatic amnesia
( p ¼ 0.08; odds ratio ¼ 6.4, 95% CI ¼ 0.761.2). The athletes with multiple con-
cussions were six times more likely to experience sideline-assessed post-traumatic
amnesia. Moreover, the athletes with a history of multiple concussions were signifi-
cantly more likely to evidence 5 or more min of sideline-assessed, broadly defined,
mental status disturbance ( p ¼ 0.036; odds ratio ¼ 8.3, 95% CI ¼ 0.977.6).
The main findings of the current study were that young athletes who sustain mul-
tiple concussions reported significantly more symptoms and demonstrated a clear
trend toward lower memory scores at baseline. Given the closely matched samples,
the preseason symptom and memory findings were interpreted to be suggestive of
cumulative, lingering effects of multiple concussions. In addition, athletes with
multiple concussions showed worse on-field severity markers associated with their
next concussion as compared with athletes who were experiencing their first con-
cussion. They were six times more likely to experience post-traumatic amnesia and
approximately eight times more likely to experience 5 or more min of mental status
disturbance, broadly defined (i.e. RTA, PTA or disorientation). Finally, athletes
with multiple concussions had more adverse consequences in the acute recovery
period (i.e. 2 days) from their next concussion. That is, multiply concussed players
performed much lower on the memory testing at 2 days post-injury than the singly
concussed players. Athletes with multiple concussions were eight times more likely
Baseline 1-2 Days Post Injury
No Concussions Multiple Concussions
Figure 2. ImPACT memory composite scores for the two groups.
440 G. L. Iverson et al.
to evidence a marked drop in memory functioning from baseline to 2 days post-
injury (i.e. a 1.5 pooled SD drop in functioning). A major strength of this study was
the careful matching of athletes on important demographic variables. Major limita-
tions include the retrospective, quasi-experimental component of the study and the
small sample sizes.
The present findings are consistent with those of Gaetz et al. [23] who reported
that at baseline, subjects who sustained three or more concussions reported greater
numbers of post-concussion symptoms than those who had never sustained a con-
cussion. Variables such as headache, memory problems, and problems with ‘the
ability to think’ were more highly endorsed by those with multiple concussions.
In addition, athletes had significant increases in event-related potential latency
compared with the group with no concussions. The results are also consistent
with the findings of Collins et al. [11] in a large sample of college football players.
Those with two or more concussions reported more symptoms and performed
more poorly on two information processing speed tests than athletes with no
prior concussions.
The results of the present study have potentially important implications for the
clinical care of concussed athletes. If indeed multiple concussive injuries result in a
decline in neuropsychological performance over time, this information may be
important in helping athletes and there families make informed decisions about
the risk of continued participation in contact sports.
Not all recent studies reported evidence for cumulative effects. For example,
Macciocchi et al. reported that in matched groups of football players with either one
or two concussions, no statistical differences were observed on neuropsychological
tests such as the PASAT, Trails A and B, or the Symbol Digit Test [34]. However,
their sample sizes were very small (i.e. n ¼ 12). Perhaps there is a point where
statistical increases in symptoms occur following multiple concussions. There
might be a linear progression where cognitive problems and subjective symptoms
increase with the number of concussions sustained. Of course, severity of concus-
sion is likely as important, or even more important, than number of concussions.
Further research is required to understand these issues better.
Researchers have reported post-concussion symptoms in trauma patients who
are 1 or more years post-injury [35–37]; however, the underlying causes of these
persistent, long-term symptoms are subject to considerable debate. Moreover,
a carefully controlled, large-scale, prospective study of trauma patients with uncom-
plicated mild traumatic brain injuries demonstrated that long-term post-concussion
symptoms were rare [38]. In addition, it is well known that the so-called post-
concussion symptoms are non-specific; they occur in day-to-day life and are associ-
ated with multiple other factors and conditions such as depression, chronic pain, life
stress and personal injury litigation [39–46]. Therefore, it is possible that due to
some unknown sampling bias, the present study has inadvertently selected a group
of multiply concussed players who have increased baseline symptom reporting as
a result of other factors. Although possible, this seems unlikely. Nonetheless, repli-
cation of the current results, ideally with a larger sample, is recommended.
In conclusion, this study provides preliminary and provocative evidence to
suggest that young athletes with multiple concussions might have cumulative
effects. Specifically, these athletes are more likely to report ongoing post-concussion
symptoms, and they performed slightly worse on preseason memory testing.
Moreover, they appear to be more susceptible to sustaining injuries of greater
Cumulative effects of concussion in amateur athletes 441
severity in the future. Finally, those athletes with multiple concussions had greater
adverse consequences in the acute recovery period (i.e. 2 days) from their next
1. POWELL, J. W. and BARBER-FOSS, K. D.: Traumatic brain injury in high school athletes. Journal of
the American Medical Association, 282: 958–963, 1999.
2. H
UGENTOLTZ, H., STUSS, D. T., STETHEM, L. L. and RICHARD, M. T.: How long does it take to
recover from mild concussion? Neurosurgery, 22: 853–858, 1988.
3. L
W. M. and F
RANKOWSKI, R. F.: Neurobehavioral outcome following minor head injury: A three-
center study. Journal of Neurosurgery, 66: 234–243, 1987.
4. M
ACCIOCCHI, S., BARTH, J., ALVES, W., RIMEL, R. and JANE, J.: Neuropsychological functioning
and recovery after mild head injury in collegiate athletes. Neurosurgery, 39: 510–514, 1996.
5. P
and N
G, K.: Factors influencing outcome following mild traumatic brain injury in adults. Journal of
the International Neuropsychological Society, 6: 568–579, 2000.
6. D
IKMEN, S. S., MACHAMER, J. E., WINN, H. R. and TEMKIN, N. R.: Neuropsychological outcome
at 1-year post head injury. Neuropsychology, 9: 80–90, 1995.
7. G
OLDSTEIN, F. C., LEVIN, H. S., GOLDMAN, W. P., CLARK, A. N. and ALTONEN, T. K.: Cognitive
and neurobehavioral functioning after mild versus moderate traumatic brain injury in older adults.
Journal of the International Neuropsychological Society, 7: 373–383, 2001.
8. P
and N
G, K.: Cognitive and behavioral outcome following mild traumatic head injury in children.
Journal of Head Trauma Rehabilitation, 14: 360–372, 1999.
9. G
OLDSTEIN, F. C. and LEVIN, H. S.: Neurobehavioral outcome of traumatic brain injury in older
adults: initial findings. Journal of Head Trauma Rehabilitation, 10: 57–73, 1995.
10. C
ANTU, R. C. and VOY, R.: Second impact syndrome: a risk in any sport. Physician Sport Medicine,
2327–2336, 1995.
11. C
M., C
D. B.: Relationship between concussion and neuropsychological performance in college football
players. Journal of the American Medical Association, 282: 964–970, 1999.
12. E
CHEMENDIA, R. J., PUTUKIAN, M., MACKIN, S., JULIAN, L. and SHOSS, N.: Neuropsychological test
performance prior to and following sports-related mild traumatic brain injury. Clinical Journal of
Sport Medicine, 11: 23–31, 2001.
13. H
INTON-BAYRE, A. D., GEFFEN, G. and MCFARLAND, K.: Mild head injury and speed of informa-
tion processing: a prospective study of professional rugby league players. Journal of Clinical and
Experimental Neuropsychology, 19: 275–289, 1997.
14. M
ARTLAND, H. S.: Punch-drunk. Journal of the American Medical Association, 19: 1103–1107, 1928.
15. S
EREL, M. and JAROS, O.: The mechanisms of cerebral concussion in boxing and their conse-
quences. World Neurology, 3: 351–358, 1962.
16. M
AWDSLEY, C. and FERGUSON, F. R.: Neurological disease in boxers. Lancet, ii: 795–801, 1963.
17. P
EERLESS, S. and REWCASTLE, N.: Shear injuries of the brain. Canadian Medical Association Journal,
96: 577–582, 1967.
18. K
ELLY, J. P. and ROSENBERG, J. H.: Diagnosis and management of concussion in sport. Neurology,
48: 575–580, 1997.
19. T
EGNER, Y. and LORENTZON, R.: Concussion among Swedish elite ice hockey players. British
Journal of Sport Medicine , 30: 251–255, 1996.
20. G
evidence of impaired neurocognitive performance in college soccer players. American Journal of
Sport Medicine, 30: 157–162, 2002.
21. M
ATSER, E. J. T., KESSELS, A. G., LEZAK, M. D., JORDAN, B. and TROOST, J.: Cumulative problems
with memory and planning in amateur soccer. Journal of the American Medical Association, 282: 971–
973, 1999.
22. G
RONWALL, D. and WRIGHTSON, P.: Cumulative effects of concussion. Lancet, ii: 995–997, 1975.
442 G. L. Iverson et al.
23. GAETZ, M., GOODMAN, D. and WEINBERG, H.: Electrophysiological evidence for the cumulative
effects of concussion. Brain Injury, 14: 1077–1088, 2000.
24. O
MMAYA, A. A. and GENNARELLI, T. A.: Cerebral concussion and traumatic unconsciousness:
correlation of experimental and clinical observations on blunt head injury. Brain, 97: 633–654,
25. G
ENNARELLI, T. A.: The spectrum of traumatic injury. Neuropathology and Applied Neurobiology, 22:
509–513, 1996.
26. G
OVLISHOCK, J. T.: The use of antibodies targeted against the neurofilament subunits for the
detection of diffuse axonal injury in humans. Journal of Neuropathology and Experimental
Neurology, 52: 143–152, 1993.
27. O
PPENHEIMER, D. J.: Microscopic lesions of the brain following head injury. Journal of Neurology,
Neurosurgery, and Psychiatry, 31: 299–306, 1968.
28. P
OVLISHOCK, J. T.: Pathobiology of traumatically induced axonal injury in animals and man.
Annals of Emergency Medicine, 22: 980–986, 1993.
29. Y
AGHMAI, A. and POVLISHOCK, J.: Traumatically induced reactive change as visualized through the
use of monoclonal antibodies targeted to the neurofilament subunits. Journal of Neuropathology and
Experimental Neurology, 51: 158–176, 1992.
30. U
NTERHARNSCHEIDT, F. J.: About boxing: review of the historical and medical aspects. Texas
Reports on Biology and Medicine, 28: 421–495, 1970.
31. U
NTERHARNSCHEIDT, F. J.: Injuries due to boxing and other sports. In: P. J. Vinken and G. W.
Bruyn (editors) Handbook of Clinical Neurology (Amsterdam: North Holland), pp. 527–593, 1975.
32. L
OVELL, M. R. and COLLINS, M. W.: Neuropsychological assessment of the college football player.
Journal of Head Trauma Rehabilitation, 13: 9–26, 1998.
33. L
OVELL, M. R.: Evaluation of the professional athlete. In: J. Bailes, M. R. Lovell and J. C. Maroon
(editors) Sports-related Concussion (St Louis: Quality Medical Publ.), 1999.
34. M
ACCIOCCHI, S. N., BARTH, J. T., LITTLEFIELD, L. and CANTU, R. C: Multiple concussions and
neuropsychological functioning in collegiate football players. Journal of Athletic Training, 36: 303–
306, 2001.
35. B
outcome of mild head injury: results from a controlled postal survey. Brain Injury, 8: 701–708,
36. D
EB, S., LYONS, I. and KOUTZOUKIS, C.: Neuropsychiatric sequelae one year after a minor head
injury. Journal of Neurology, Neurosurgery, and Psychiatry, 65: 899–902, 1998.
37. R
UTHERFORD, W. H., MERRETT, J. D. and McDONALD, J. R.: Symptoms at one year following
concussion from minor head injuries. Injury, 10: 225–230, 1978.
38. A
LVES, W., MACCIOCCHI, S. N. and BARTH, J. T.: Postconcussive symptoms after uncomplicated
mild head injury. Journal of Head Trauma Rehabilitation, 8: 48–59, 1993.
39. D
UNN, J. T., LEES-HALEY, P. R., BROWN, R. S., WILLIAMS, C. W. and ENGLISH, L. T.: Neurotoxic
complaint base rates of personal injury claimants: implications for neuropsychological assessment.
Journal of Clinical Psychology, 51: 577–584, 1995.
40. F
OX, D. D., LEES-HALEY, P. R., EARNEST, K. and DOLEZAL-WOOD, S.: Post-concussive symptoms:
Base rates and etiology in psychiatric patients. Clinical Neuropsychologist, 9: 89–92, 1995.
41. G
OUVIER, W. D., UDDO-CRANE, M. and BROWN, L. M.: Base rates of post-concussional symp-
toms. Archives of Clinical Neuropsychology, 3: 273–278, 1998.
42. I
VERSON, G. L. and MCCRACKEN, L. M.: ‘Postconcussive’ symptoms in persons with chronic pain.
Brain Injury, 11: 783–790, 1997.
43. L
EES-HALEY, P. R. and BROWN, R. S.: Neuropsychological complaint base rates of 170 personal
injury claimants. Archives of Clinical Neuropsychology, 8: 203–209, 1993.
44. M
ACHULDA, M. M., BERGQUIST, T. F., ITO, V. and CHEW, S.: Relationship between stress, coping,
and postconcussion symptoms in a healthy adult population. Archives of Clinical Neuropsychology,
13: 415–424, 1998.
45. S
AWCHYN, J. M., BRULOT, M. M. and STRAUSS, E.: Note on the use of the Postconcussion
Syndrome Checklist. Archives of Clinical Neuropsychology, 15: 1–8, 2000.
46. W
ONG, J. L., REGENNITTER, R. P. and BARRIOS, F.: Base rate and simulated symptoms of mild
head injury among normals. Archives of Clinical Neuropsychology, 9: 411–425, 1994.
Cumulative effects of concussion in amateur athletes 443
... De nombreuses études ont depuis été mises en place dans les championnats professionnels et universitaires américains pour évaluer les risques de survenue de commotions cérébrales chez les joueurs, notamment pour ceux en ayant déjà subi au moins une au cours de la saison (Guskiewicz et al. 2003(Guskiewicz et al. , 2000Iverson et al. 2004;Kuo et al. 2017;Pellman et al. 2003). Il a ainsi été observé sur une cohorte de 17549 joueurs que la survenue d'une commotion était liée au niveau de pratique du joueur ; plus il est élevé, moins le risque de survenue est important (Guskiewicz et al. 2000). ...
... Il a ainsi été observé sur une cohorte de 17549 joueurs que la survenue d'une commotion était liée au niveau de pratique du joueur ; plus il est élevé, moins le risque de survenue est important (Guskiewicz et al. 2000). L'incidence observée est 3 fois plus importante chez les joueurs ayant subi une commotion dans la saison que chez les autres, 7.7 pour (Iverson et al. 2004), et si 8.9% de ces accidents ont engendré une perte de connaissance, 86% des joueurs ont déclaré souffrir de maux de tête les jours qui ont suivi. Enfin, il a été montré d'après (Guskiewicz et al. 2000) que 30.8% des joueurs ayant subi une commotion cérébrale restaient en jeu. ...
La commotion cérébrale est un traumatisme fréquemment rapporté dans les sports de contact mais dont la physiopathologie demeure un sujet d’étude notamment dans ses modalités de survenue. La modélisation éléments finis constitue alors une approche particulièrement adaptée pour évaluer plus localement l’état mécanique des structures étudiées. Bien que le mécanisme lésionnel de la commotion cérébrale soit directement lié aux conditions limites appliquées au sujet, l’influence de la variabilité morphologique des structures mises en jeu n’a en revanche jamais été évaluée. L'objectif de ces travaux est de contribuer à la compréhension du mécanisme lésionnel à travers une modélisation géométrique paramétrée, et personnalisable, du crâne et des principales structures qu’il contient [cerveau, cervelet, tronc cérébral, faux du cerveau et tente du cervelet, ventricules, principaux sinus]. Après avoir évalué l’inter variabilité morphologique des composants étudiés et développé une méthode de génération automatique des maillages de ces structures, pouvant être personnalisés à partir d’imagerie médicale, une étude préliminaire a ensuite été réalisée pour évaluer l’influence de la géométrie structurelle, pour des cas d’impacts référencés, sur la réponse biomécanique de la tête.
... found that individuals who had suffered either 2+ or 3+ mTBIs had significantly worsened cognitive outcomes [27][28][29] several years following the injury, although several others have found no association. 30,31 Most of these studies examining the cognitive effect of multiple mTBI examined only athletes, focussed on those in their 20s, were crosssectional in design, and did not follow participants for more than 7 years. ...
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Traumatic brain injury (TBI) causes cognitive impairment but it remains contested regarding which cognitive domains are most affected. Further, moderate-severe TBI is known to be deleterious, but studies of mild TBI (mTBI) show a greater mix of negative and positive findings. This study examines the longer-term cognitive effects of TBI severity and number of mTBIs in later life. We examined a subset (n = 15,764) of the PROTECT study, a cohort assessing risk factors for cognitive decline (ages between 50 and 90 years). Participants completed cognitive assessments annually for 4 years. Cognitive tests were grouped using a principal components analysis (PCA) into working memory, episodic memory, attention, processing speed, and executive function. Lifetime TBI severity and number were retrospectively recalled by participants using the Brain Injury Screening Questionnaire (BISQ). Linear mixed models (LMMs) examined the effect of severity of head injury (non-TBI head strike, mTBI, and moderate-severe TBI) and number of mTBI at baseline and over time. mTBI was considered as a continuous and categorical variable (groups: 0 mTBI, 1 mTBI, 2 mTBIs, 3 mTBIs, and 4+ mTBIs). Of the participants 5725 (36.3%) reported at least one mTBI and 510 (3.2%) at least one moderate-severe TBI, whereas 3711 (23.5%) had suffered at worst a non-TBI head strike and 5818 (32.9%) reported no head injuries. The participants had suffered their last reported head injury an average (standard deviation, SD) of 29.6 (20.0) years prior to the study. Regarding outcomes, there was no worsening in longitudinal cognitive trajectories over the study duration but at baseline there were significant cognitive deficits associated with TBI. At baseline, compared with those without head injury, individuals reporting at least one moderate-severe TBI had significantly poorer attention (B = -0.163, p < 0.001), executive scores (B = -0.151, p = 0.004), and processing speed (B = -0.075, p = 0.033). Those who had suffered at least a single mTBI also demonstrated significantly poorer attention scores at baseline compared with the no head injury group (B = -0.052, p = 0.001). Compared with those with no mTBI, those in the 3 mTBI group manifested poorer baseline executive function (B = -0.149, p = 0.025) and attention scores (B = -0.085, p = 0.015). At baseline, those who had suffered four or more mTBIs demonstrated poorer attention (B = -0.135, p < 0.001), processing speed (B = -0.072, p = 0.009), and working memory (B = -0.052, p = 0.036), compared with those reporting no mTBI. TBI is associated with fixed, dose, and severity-dependent cognitive deficits. The most sensitive cognitive domains are attention and executive function, with approximately double the effect compared with processing speed and working memory. Post-TBI cognitive rehabilitation should be targeted appropriately to domain-specific effects. Significant long-term cognitive deficits were associated with three or more lifetime mTBIs, a critical consideration when counseling individuals post-TBI about continuing high-risk activities.
... Professional AFL players often report numerous concussions during their sporting careers 72 , and there is increasing evidence regarding the deleterious effects of repeat concussions 96,97 . ...
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Sports-related concussion, a form of mild traumatic brain injury, is characterised by transient disturbances of brain function. There is increasing evidence that functional brain changes may be driven by subtle abnormalities in white matter microstructure, and diffusion MRI has been instrumental in demonstrating these white matter abnormalities in vivo. However, the reported location and direction of the observed white matter changes in mild traumatic brain injury are variable, likely attributable to the inherent limitations of the white matter models used. This cross-sectional study applies an advanced and robust technique known as fixel-based analysis to investigate fibre tract-specific abnormalities in professional Australian Football League players with a recent mild traumatic brain injury. We used the fixel-based analysis framework to identify common abnormalities found in specific fibre tracts in participants with an acute injury (≤ 12 days after injury; n = 14). We then assessed whether similar changes exist in subacute injury (> 12 days and < 3 months after injury; n = 15). The control group was 29 neurologically healthy control participants. We assessed microstructural differences in fibre density and fibre bundle morphology and performed whole-brain fixel-based analysis to compare groups. Subsequent tract-of-interest analyses were performed within five selected white matter tracts to investigate the relationship between the observed tract-specific abnormalities and days since injury and the relationship between these tract-specific changes with cognitive abnormalities. Our whole-brain analyses revealed significant increases in fibre density and bundle cross-section in the acute mild traumatic brain injury group when compared to controls. The acute mild traumatic brain injury group showed even more extensive differences when compared to the subacute injury group than to controls. The fibre structures affected in acute concussion included the corpus callosum, left prefrontal and left parahippocampal white matter. The fibre density and cross-sectional increases were independent of time since injury in the acute injury group, and were not associated with cognitive deficits. Overall, this study demonstrates that acute mild traumatic brain injury is characterised by specific white matter abnormalities, which are compatible with tract-specific cytotoxic oedema. These potential oedematous changes were absent in our subacute mild traumatic brain injury participants, suggesting that they may normalise within 12 days after injury, although subtle abnormalities may persist in the subacute stage. Future longitudinal studies are needed to elucidate individualised recovery after brain injury.
... 9 However, athletes with 3 or more concussions had more reported symptoms and reduced performance on the computerized ImPact test. 10 Other studies have produced mixed and mostly undetectable effects of preceding concussions on baseline neurocognitive tests. [11][12][13] Symptom resolution and normal baseline performance of neurologic tests, however, cannot adequately address the issue of lingering impairment of a concussed brain. ...
Objective: Patients who are fully recovered from a concussion may still be more vulnerable in the face of subsequent concussions. This study examines symptoms associated with repeated concussions in young and otherwise healthy adults. Design: Cross sectional. Setting: Institutional study at a university setting. Participants: University students with a history of concussion. Independent variables: Participants were grouped based on numbers of concussions. Main outcome measures: The impact of incremental concussion on symptom clusters in Sport Concussion Assessment Tools 5 and Spearman ranking correlation coefficients between symptom clusters. Results: One hundred thirty-five participants reported having had 1 concussion, 63 reported 2 concussions, 50 reported 3 concussions, and 43 reported 4 to 6 concussions. Total severity scores over the range of concussion number (1, 2, 3, and greater than 3) did not show a clear incremental effect. However, average scores of cognitive symptoms rose with each subsequent concussion (P ≤ 0.05). The largest incremental effect observed was that of second concussions on emotional symptom scores (t = 5.85, P < 0.01). Symptoms in the emotional and cognitive clusters were the most correlated regardless of the number of reported concussions; the correlations were lowest with symptoms associated with sensitivity to light or noise. Conclusions: The incremental rise of cognitive symptom scores with each concussion affirms the importance of cognitive impairment in concussion assessment and implies a cumulative brain vulnerability that persists even after symptom resolution. The cognitive-emotional symptom clusters may reflect underlying concussion-induced impairments in the corticostriatothalamocortical (CSTC) networks, although sensitivity symptoms are potentially attributable to different neural correlates.
Sports-related concussions (SRC) are frequent injuries occurring in most contact and collision sports across all ages and all levels of play. Once thought of as a “ding” or simply “part of the game,” it is now understood that concussions are brain injuries that can have significant neurocognitive consequences if not evaluated and managed appropriately. This chapter reviews the definition of concussion, mechanism of injury, the pathophysiology underlying the injury, epidemiology, and the clinical management of players who have sustained a concussion. The focus then turns to prevention of the injury and, more importantly, the prevention of deleterious consequences from improper management. Various prevention strategies are discussed ranging from education to legislative reform.KeywordsSports concussionNeuropsychological assessmentConcussion pathophysiologyConcussion advocacyConcussion prevention
American football remains one of the most popular sports for young athletes. The injuries sustained during football, especially those to the head and neck, have been a topic of intense interest recently in both the public media and medical literature. The recognition of these injuries and the potential for long-term sequelae have led some physicians to call for a reduction in the number of contact practices, a postponement of tackling until a certain age, and even a ban on high school football. This statement reviews the literature regarding injuries in football, particularly those of the head and neck, the relationship between tackling and football-related injuries, and the potential effects of limiting or delaying tackling on injury risk.
Background: Nearly 2 million youth seek acute medical care following concussion in the U.S. each year. Current standard of care recommends rest for the first 48 h after a concussion. However, research suggests that prolonged rest may lengthen recovery time especially for patients with certain risk profiles. Research indicates that physical activity and behavioral management interventions (sleep, stress management) may enhance recovery. To date, there is limited empirical evidence to inform acute (<72 h) concussion recommendations for physical activity and behavioral management in adolescents. Objective: To determine the effectiveness of physical activity and behavioral management for acute concussion in adolescents and young adults, and to evaluate the role of patient characteristics on treatment response. Methods: This multicenter prospective randomized controlled trial will determine which combination of physical activity and behavioral management is most effective for patients 11-24 years old who present to the emergency department or concussion clinic within 72 h of injury. Participants are randomized into: 1) rest, 2) physical activity, 3) mobile health application (mHealth) behavioral management, or 4) physical activity and mHealth app conditions. Assessments at enrollment, 3-5 days, 14 days, 1 month, and 2 months include: concussion symptoms, balance, vestibular-ocular and cognitive assessments, quality of life, and recovery time. Somatic symptoms and other risk factors are evaluated at enrollment. Compliance with treatment and symptoms are assessed daily using actigraph and daily self-report. The primary study outcome is symptoms at 14 days. Conclusion: Prescribed physical activity and behavioral management may improve outcomes in youth following acute concussion.
Background: The symptom presentation after sport-related concussion is highly subjective, while the clinical test of reaction time (RT) has been presented as an objective tool to the effects of sport-related concussion. A multimodal assessment approach supports concussion management; therefore, it is appropriate to explore the relationship between modals. The aim of the present study is to investigate the relationship of clinical RT and post-concussion symptom (PCS) score, number of experienced concussions, and time since concussion. Methods: Based on retrospective concussion history, 53 athletes were selected for this study. Athletes were questioned using a standardized questionnaire to obtain concussion history data, such as number of cumulative concussions and date of most recent concussion. Symptom scores were gathered through Sport Concussion Assessment Tool. A clinical RT test was used to obtain RT data. Results: A significant positive correlation was found between RT and the PCS score. A linear regression revealed that the PCS score but neither the cumulative number of experienced concussions, nor the time post-concussion significantly predicts increased RT. Reaction time positively correlates with the symptoms neck pain, dizziness, balance problems, light sensitivity, feeling slowed down, feeling like in a fog, do not feel right, drowsiness, and irritability. Conclusions: This study presents that the PCS score particularly predicts increased RT after sport-related concussions. Furthermore, a specific set of symptoms significantly impacts the RT of athletes. The results suggest that not a single symptom drives the relationship between PCS score and RT, highlighting the heterogeneity of this injury.
Objective: International consensus statements highlight the value of neuropsychological testing for sport-related concussion. Computerized measures are the most frequently administered assessments of pre-injury baseline and post-injury cognitive functioning, despite known measurement limitations. To our knowledge, no studies have explored the convergent validity of computerized Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) and traditional, well-validated paper and pencil (P&P) neuropsychological tests in high school student athletes. This study aimed to assess a "hybrid" adolescent test battery composed of ImPACT and P&P measures to determine the extent of shared variance among ImPACT and P&P tests to inform comprehensive yet streamlined assessment. Method: Participants included male and female high school student athletes in the Southeastern United States participating in American football, hockey, and soccer who completed a battery of ImPACT and P&P tests (N = 69). Results: We performed principal component analysis with ProMax rotation to determine components of the hybrid battery that maximally accounted for observed variance of the data (Kaiser-Meyer-Olkin factor adequacy = 0.71). Our analysis revealed four independent factors (Verbal Learning and Memory, ImPACT Memory and Speed, Verbal Processing Speed/Executive Functions, and Nonverbal Processing Speed/Executive Functions) explaining 75% of the variance. Conclusions: Findings of this study in adolescent student athletes support those from the adult literature demonstrating the independence of ImPACT and P&P tests. Providers should be aware of limitations in using standalone ImPACT or P&P measures to evaluate cognitive functioning after concussion. If confirmed in a larger, clinical sample, our findings suggest that a hybrid battery of computerized and P&P measures provides a broad scope of adolescent cognitive functioning to better inform recovery decisions, including return to play after concussion.
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This study was intended to provide a normative comparison base for estimating the rates of neuropsychological symptoms in psychiatric patients. Four hundred individuals seeking psychotherapy were administered a checklist composed of symptoms reported to be common in the post-concussional syndrome (PCS). Of the entire sample, 9% of the patients reported a recent history of bumping their head (BUMP), 3.5% reported being knocked out (LOC), and 9% were involved in a lawsuit (LITS). Many, but not all of the PCS symptoms were as common among the BUMP and LITS groups as the LOC group. There are suggestions that some PCS symptoms are related to head trauma while others reflect situational variables or general psychological distress.
The known risk of second impact syndrome (SIS) in football has elevated the importance of postconcussion and precompetition exams of injured football players. Six case reports demonstrate that the same mechanism of injury—minor head trauma in a player who still has symptoms from a previous concussion—can cause second impact syndrome in any contact sport. It is important to monitor postconcussion symptoms, which include headache, light-headedness, and impaired consciousness. Return-to-play guidelines for football and boxing provide a basis for making safe activity recommendations for other sports.
Purpose: A study was initiated with the intent of demonstrating the cumulative effects of concussion in junior hockey players using visual event-related potentials and post-concussion syndrome (PCS) self-reports. Methods: Players were assessed at the beginning of the season (pre-injury) and at various times post-injury. Results: The results suggest that players with three or more concussions differed significantly on the several cognitive PCS symptoms as well as for the latency of the P3 response compared to those with no concussion history. Discussion: Event-related potentials are useful indices of the cumulative damage that can occur following multiple concussions. These measures correlate significantly with cognitive self-reports of PCS symptoms. Conclusions: This pattern of results is consistent with the position that each concussion potentially causes brain damage. Cumulative damage can be detected using electrophysiological measures of brain function.
Context Soccer players incur concussions during matches and training sessions, as well as numerous subconcussive blows to the head from impacts with the soccer ball (headers). The combination of soccer-related concussions and the number of headers may be a risk for chronic traumatic brain injury (CTBI).Objective To determine whether amateur soccer players have evidence of CTBI.Design, Setting, and Participants Cross-sectional study of 33 amateur soccer players and 27 amateur athletes involved in swimming and track (controls) in the Netherlands who underwent interviews and neuropsychological testing.Main Outcome Measures Performance of soccer players vs controls on 16 neuropsychological tests having 27 outcomes.Results Compared with control athletes, amateur soccer players exhibited impaired performance on tests of planning (39% vs 13%; P=.001) and memory (27% vs 7%; P=.004). Among soccer players, 9 (27%) had incurred 1 soccer-related concussion and 7 (23%) had had 2 to 5 concussions during their career. The number of concussions incurred in soccer was inversely related to the neuropsychological performance on 6 of the neuropsychological tests.Conclusions Our results indicate that participation in amateur soccer in general and concussion specifically is associated with impaired performance in memory and planning functions. Due to the worldwide popularity of soccer, these observations may have important public health implications.
For some time fight fans and promoters have recognized a peculiar condition occurring among prize fighters which, in ring parlance, they speak of as "punch drunk." Fighters in whom the early symptoms are well recognized are said by the fans to be "cuckoo," "goofy," "cutting paper dolls," or "slug nutty."Punch drunk most often affects fighters of the slugging type, who are usually poor boxers and who take considerable head punishment, seeking only to land a knockout blow. It is also common in second rate fighters used for training purposes, who may be knocked down several times a day. Frequently it takes a fighter from one to two hours to recover from a severe blow to the head or jaw. In some cases consciousness may be lost for a considerable period of time.The early symptoms of punch drunk usually appear in the extremities. There may be only an occasional
Neuropsychological outcome at 1 year postinjury was examined prospectively in representative groups of 436 adult head-injured participants and 121 general-trauma control participants. A comprehensive battery of neuropsychological measures was administered. The head-injured group performed significantly worse than the trauma controls on most measures (p < .01). However, the magnitude and pervasiveness of the impairments depended on the severity of the head injury. This study provides information about expected ranges of impairment as a function of different severity levels and appropriate comparison values. The findings raise important questions about clinically held beliefs of differential sensitivity of neuropsychological measures. Furthermore, the substantial variability in outcome observed underscores the importance of examining factors that seem to exacerbate or mitigate the effects of brain damage.
Postconcussive symptomatology was studied in 587 patients with uncomplicated mild head injury. There was a linear decrease in symptomatology over the 1-year follow-up period. Headache was the most frequently reported postconcussive symptom. Symptom constellations consistent with postconcussive syndrome were rare. A number of patients reported symptoms at 1 year follow-up. Interventions designed to provide education and support appeared to be associated with symptom resolution in some patients. Implications of these findings are discussed. (C) Williams & Wilkins 1993. All Rights Reserved.