Newsgroup: it.sport.arti-marziali
Titolo: trauma cranico e sport (lungo)

Cari amici,
ho visto il lungo thread sul distacco di retina ... e non sono intervenuto
perchè la risposta da parte di un medico mi sembra lapalissiana :-)) - ad
ogni buon conto ho trovato questo articolo nei meandri del mio hard disk e
lo posto, per chi volesse documentarsi di più sull'argomento. Come vedete
nella bibliografia è citato il pugilato ma anche il taekwondo ... e il
football americano, il calcio e infine lo sport + pericoloso di tutti che
risulta essere : l'equitazione !!!
--
Tae Kyon
"Il fine supremo del Taekwon Do: Accrescere nell'uomo la saggezza, far
nascere e sviluppare nel suo animo la dignità, la consapevolezza delle
proprie capacità fisiche e morali, allontanandolo da qualsiasi atto di
violenza e di ingiustizia"      (Choi Hong Hi)
***********************************************************************
Mild Head Injury in Sports
Robert A. Ruchinskas, Joseph P. Francis, Jeffrey T. Barth, University of
Virginia Health Sciences Center, Charlottesville, Virginia, USA
[Applied Neuropsychology 4(1):43-49, 1997. © 1998 Lawrence Erlbaum
Associates, Inc.]
Abstract
Mild head injury has been recognized as producing numerous "postconcussive"
symptoms that temporarily reduce an individual's ability to function.
Controversy exists over the short- and long-term effects of mild head
injuries, and the effects of repeated concussive blows to the head have not
been sufficiently studied. Amateur and professional athletes provide an
excellent population for the examination of many aspects of postconcussive
syndrome. The nature, incidence, and cognitive and emotional symptoms of
mild head injury are reviewed within the framework of professional and
amateur sports. Particular attention is paid to the few available
prospective studies of amateur boxers and collegiate football players.
Introduction
A relatively rare event occurred during the 1993 National Football League's
conference playoffs. In the American Football Conference's championship
game, quarterback Joe Montana experienced what is now a common refrain:
getting hit on a play, having his head bounce off of the turf, temporarily
losing consciousness, and having a loss of memory for the incident. This was
an unusual occurrence, yet less than 3 hr later, Troy Aikman, one of the
starting quarterbacks for the day's second game, left the game early after
being kneed in the head. The team trainer called Aikman's condition a
"concussion" in that he had a brief period of unconsciousness and was
disoriented on awakening. The odds of two starting quarterbacks sustaining
mild head injuries with short losses of consciousness (concussion) on the
same day are relatively low. Among reported injuries, the chances of any
athlete incurring mild head trauma are generally between 2% and 10%, but
range as high as 91% for equestrian accidents. Although head injuries can
occur in virtually any sport or recreational activity, Table 1 lists the
sports in which head injury rates are described in the literature.
Along with the low probability of injury, an expectation of a rapid and full
recovery from a mild head injury is present (as was seen in Aikman's
performance in the Super Bowl 1 week later). However, cases of complicated
recoveries from concussions have been reported in which cognitive and
emotional sequelae are long lasting (e.g., Barth et al., 1983; Rimel,
Giordani, Barth, Boll, & Jane, 1981). In addition, recent attention has been
focused on well-publicized cases of football and hockey athletes prematurely
retiring after sustaining multiple mild head injuries. Hence, there is a
small but growing body of literature devoted to examining mild head injury
in athletes, particularly in boxing, football, and more recently, soccer.
The goals of this research are threefold: (a) to increase safety for the
athletes, (b) to aid in understanding the mechanisms and recovery from
simple (uncomplicated) and complicated mild head injuries that occur in more
common settings (automobile accidents, falls, etc.), and (c) to broaden
limited scientific knowledge regarding the effects of repeated mild head
injuries. Professional and amateur athletes tend to be good research
participants because they do not have many of the risks or complicating
factors for spontaneous cognitive decline (age, poor health, substance
abuse, etc.). Unfortunately, athletes tend to underreport head injuries, and
injuries in general, for fear of letting down the team, being seen as weak,
or reducing their probability of playing in the next game (Gerberich,
Priest, Boen, Staub, & Maxwell, 1983).
What Is Mild Head Injury?
The theory and subsequent study of mild head injury is still in its infancy.
Over the last 15 years, scientists have been examining the mechanisms of
mild head injury and resultant postconcussive syndrome. Mild head injury
refers to brief losses of or changes in consciousness (awareness) following
a blow to the head. Such injuries rarely result in identifiable cerebral
lesions, yet like moderate and severe head trauma, can be associated with
contusions (bruises), most commonly occurring on the frontal and temporal
lobes. Underlying white matter may be affected by edema, along with shearing
and cytoskeletal injury of neuronal axons (Duckett & Duckett, 1993).
Research (Dixon, Taft, & Hayes, 1993) has also suggested a myriad of acute
and chronic changes in neurochemical functions in the brain following injury
(e.g., neurotransmitter release/deficits, changes in receptor binding,
alterations in cholinergic functioning, etc.). Although CT and MRI scans are
useful in detecting bleeding and swelling in more severe traumatic injuries,
they are less able to detect the more subtle, microscopic lesions that are
more typical of mild head injury.
Classification of head injury is often accomplished by using the Glasgow
Coma Scale (GCS), which assesses motor and verbal responses along with eye
opening on command to evaluate gross levels of consciousness after head
injury. A score of 13 or above (out of 15 possible) places patients in the
"mild" category for head trauma. Length of unconsciousness (less than 20
min), less than a 48-hr stay in the hospital (Rimel et al., 1981), and lack
of neuroimaging evidence (Levin, Eisenberg, & Benton, 1989) have also been
used to categorize mild head injury. Unfortunately, a consensus for
diagnostic criteria has not been achieved (Jordan, 1989), and varying
definitions of mild head injury or mild traumatic brain injury are found in
research and clinical practice (Harrington, Malec, Cicerone, & Katz, 1993).
Still, the symptoms of problematic or complicated mild head injury, termed
postconcussive syndrome are well recognized: headaches, dizziness, memory
loss, nausea, diplopia (double vision), tinnitus (ringing in the ears),
personality change (mainly irritability), attentional deficits, and
information-processing impairment (Barth et al., 1989). Prior to 1981,
conventional wisdom held that mild head injury was rather benign and that
natural recovery from such trauma occurs quite rapidly. Rimel et al. (1981)
and Barth et al. (1983), however, found that some cognitive symptoms, as
measured by neuropsychological tests, persisted for weeks or months after
injury. A significant proportion of patients with mild head injury (34%) had
not returned to work 3 months posttrauma due to their symptoms. Although
subsequent studies (Dikmen, McLean, & Temkin, 1986; Dikmen, Menamer, Winn, &
Temkin, 1995; Levin et al., 1987; McLean, Temkin, Dikmen, & Wyler, 1983)
reported a lower rate of cognitive dysfunction and little long-term
disability, the possibility of lasting effects from relatively mild head
injury is recognized. Research (Gronwall & Wrightson, 1975) has also
suggested a cumulative effect: An individual's ability to process
information was reduced if he or she had a prior mild head injury. Some case
studies (e.g., Shell, Carico, & Patton, 1993) have even documented
life-threatening complications after two mild head injuries were incurred in
1 week. These cases of the "second-impact syndrome," in which the athlete is
believed to be still at risk while symptomatic from a previous head injury,
are helping to shape decisions about when a player should return to a game.
In years past, athletic team physicians often applied "Quigley's rule" to
evaluate potential consequences of cerebral insult. Essentially, the rule
recommends discontinuing play after receiving three concussions (Schneider,
1973). Some of this research suggests that this heuristic may not be
conservative enough to protect athletes from incurring lasting cognitive
deficits, and more specific decision rules have been proposed (Cantu, 1986;
Saal & Sontag, 1987).
Moderate and Severe Head Injury in Boxing
Boxing is one of the few sports in which, detractors claim, the primary goal
is to render the opponent unconscious, cause a concussion, or inflict brain
damage (Jordan, 1987). Due to the sometimes brutal nature of the sport,
there have been many calls to abolish boxing.
Although severe head injury in boxing has many names (e.g., dementia
pugilistica, punch drunk syndrome, etc.) and has long been recognized,
science has only recently begun to examine mild head injury and the effects
of repeated blows to the head. Although the chances of a boxer dying in the
ring (0.13 per 1,000 participants, according to McCunney & Russo, 1984) are
less than those of athletes dying in horse racing, parachuting, hang
gliding, mountaineering, scuba diving, motorcycle racing, or football, the
professional boxer is at risk for chronic brain injury (Haglund & Eriksson,
1993). Reportedly, 9% to 25% of professional boxers eventually become "punch
drunk." Ryan (1987) concluded that "[studies] indicate clearly a significant
relationship between the numbers of bouts fought and the presence of
severity of chronic encephalopathy [brain damage]" (p. 38). Physicians have
observed that punch-drunkenness occurs more often in professionals than in
amateurs and in boxers notorious for being able to "take a punch," who are
sluggers rather than tacticians. Although the syndrome occurs across all
weight classes, it appears to occur in smaller men who fought heavier
opponents. Symptoms typically present in three stages, in which initial
disturbances are noted in coordination and affect or emotionality. As the
syndrome progresses, psychiatric symptoms increase along with dysarthria
(speech difficulties) and a resting tremor. The third stage includes hearing
problems, increased tremors, worsening incoordination, and decreased ability
to think clearly and to remember. Changes in personality and decreased
social skills have also been described. Symptoms similar to Parkinson's
disease can be observed and the course of this syndrome is generally
progressive (Jordan, 1987). Postmortem studies often find Alzheimer-like
levels of apolipoprotein E and amyloid plaques (Jordan et al., 1995).
Professional boxers without dementia pugilistica also display a higher rate
of cortical atrophy than do controls on neuroimaging studies (CT and MRI)
and cognitive abnormalities on neuropsychological tests (Haglund & Eriksson,
1993). Ross, Casson, Siegel, and Cole (1987) found deficits in attention,
memory, and visuospatial abilities, which correlated with the number of
professional bouts. The amount of sparring done by professionals has also
correlated with poorer performance on tests of attention, concentration, and
memory (Jordan, Matser, Zimmerman, & Zazula, 1996). Because abnormalities
may not always be evident through neurological examinations or structural
neuroimaging, neuropsychological tests are often considered the most
sensitive diagnostic methods and have been proposed as part of the routine
screening examinations of boxers (Levin & Jordan, 1993).
Mild Head Injury in Boxing
Although the mechanisms of injury (linear acceleration, rotational and
deceleration forces, and carotid injuries due to blows) remain the same for
professionals and amateurs, stricter rules offer more protection for the
amateur (Lampert & Hardman, 1984). Such boxers have fought fewer and shorter
fights than have professionals, have engaged in less sparring, and also have
worn headgear. Knockout rates are also low in amateur boxing; for instance,
1% to 4% of all fights end in a knockout (McCunney & Russo, 1984). In
addition, a certain amount of self-selection may take place in the amateur
ranks; poor boxers will lose early and often and leave the sport, whereas
proficient boxers may choose to become professionals. Generally, the punch
drunk syndrome of permanent and irreversible dysfunction seems rare for
amateurs (Jordan, 1987), making them excellent candidates for the study of
simple and repeated mild head injuries.
A large-scale retrospective study of amateur boxers in Sweden, where
professional boxing is banned, found no differences between amateur boxers
and controls with regard to general mental status, physical and neurological
examinations, neuroimaging, and personality functioning. After factoring in
age, education, and vocabulary, neuropsychological deficits were minimal
(decreased fine motor speed). The number of abnormal EEGs (a measure of
gross brain activity) for boxers was slightly higher than normal. In
general, the researchers found no clinical evidence of deficits due to
repeated blows to the head. There is, however, some question if Swedish
amateur boxing rules are stricter than their European and American
counterparts, which may have limited many potential harmful effects of
boxing (Haglund & Bergstrand, 1990; Haglund, Edman, Murelius, Oreland, &
Sachs, 1990; Haglund & Eriksson, 1993; Haglund & Persson, 1990). Holzgraefe,
Lemme, Funke, Felix, and Felton (1992) reported further evidence that only a
minority of amateur boxers demonstrate signs of structural damage to the
brain.
At the other end of the spectrum, research with 20 active boxers revealed 7
amateurs with abnormal neurological examinations, 8 with EEG abnormalities,
and 9 with deficiencies on neuropsychological testing, especially in the
areas of attention and verbal and visual memory (McLatchie et al., 1987).
Performance on neuropsychological measures before and after a fight have
also been examined. Verbal and incidental memory skills were diminished
after an amateur bout, whereas the boxers' "executive functions" (higher
order problem solving) and motor functions were found to be enhanced. This
study, however, lacked a matched control group to examine the effects of
exercise on general mental and motor abilities or practice effects
(Heilbronner, Henry, & Carson-Brewer, 1991).
Two prospective studies have attempted to address the weaknesses of the
previously noted research. Butler, Forsythe, Beverly, and Adams (1993) used
neuropsychological assessment prebout, immediately postbout, and follow-up
within 2 years. The authors found no evidence of neuropsychological
dysfunction, although their participants were relatively inexperienced (less
than 20% with 30 or more contests). A much larger (N = 393 at 2-year
follow-up) study found statistically significant tests of trend between the
total number of bouts incurred before baseline examination and changes in
memory, visuoconstructive skills, and perceptual and motor ability (although
the changes were not considered clinically significant). No significant
findings were present at follow-up, suggesting that stricter safety rules
enacted just prior to the study may be a confound. The examiners will
continue to follow this cohort to examine possible late effects of repeated
blows to the head (Stewart et al., 1994).
Finally, a recent study has attempted to integrate functional neuroimaging
and neuropsychology (Kemp, Houston, Macleod, & Pethybridge, 1995). This
research found abnormalities in neuropsychological measures and cerebral
single-photon emission computed tomography (SPECT) perfusion scans in
amateur boxers when compared with controls. Individuals with a greater
number of bouts tended to have poorer neuropsychological test scores,
although those divided into abnormal versus normal SPECT imaging did not
differ on psychometric testing. Correlating abnormal SPECT scans with number
of bouts unfortunately was not addressed.
Mild Head Injury in Football
Numerous studies have been published that report the incidence rate of
concussion in football at 2% to 5% of all injuries incurred (DeLee & Farney,
1992; Karpakka, 1993; Zemper, 1989). These rates may underestimate the
actual occurrence of head trauma, however, because "injuries" were often
defined as those reported to the trainer or those that kept a player out of
a game or practice for a day or more. One team physician titled his article
"When a Knee Injury Becomes a Head Injury" to underscore that the
grogginess, temporary amnesia, and confusion that accompany a Grade 1
concussion or "ding," are often missed, not reported, or dismissed (Magnes,
1990). It has been estimated that 85% to 90% of all sports-related
concussions are Grade 1, defined by Cantu (1986) as no loss of consciousness
and posttraumatic amnesia less than 30 min in duration.
A study of Minnesota secondary school varsity football players again
revealed that approximately 5% of injuries were diagnosed as "concussions"
requiring temporary removal from play (Gerberich et al., 1983). However, one
in five (20%) players indicated that they had previously suffered a loss of
consciousness or change in awareness consistent with undiagnosed mild
concussions. Generalizing this percentage to all high school football
players would indicate approximately 250,000 concussions each year. The
study also found that individuals who had previously sustained a loss of
consciousness were at a four times greater risk for sustaining another head
injury. On follow-up, approximately 3% of players stated some lingering
cognitive symptoms 6 to 9 months after injury. Still, most athletes surveyed
requested to return to play the same day of their injury.
In an attempt to characterize the nature, incidence, and consequences of
mild head injury, the University of Virginia prospective study evaluated
2,350 players from eight Ivy League schools, the University of Pittsburgh,
and the University of Virginia football teams (Alves, Rimel, & Nelson, 1987;
Barth et al., 1989). The 195 (8% of total sample) players who sustained a
mild head injury, defined as a change in or loss of consciousness for less
than 2 min and immediate demonstration of attention and memory problems,
were evaluated by neuropsychological testing and self-report questionnaires
up to four times postinjury. The injured players were compared with 59
players suffering orthopedic injuries and 48 non-football-playing student
participants to control for the effects of repeated testing. Forty-two
percent of the football players with head injuries indicated a history of at
least one prior minor head trauma and 12% had sustained three or more such
injuries. Results of the study generally indicate that a single mild head
injury can cause deficits in global cognitive functioning and information
processing within 24 hr of the insult. Rapid recovery generally takes place
over the next 5 to 10 days. Symptoms unique to postconcussive syndrome, such
as headache, nausea, dizziness, weakness, and memory problems, also appeared
to resolve over the 5- to 10-day postinjury period. Consistent with other
studies, more than 90% of head trauma was mild (a "ding"); hence, football
players have significantly greater chances of incurring injuries to a knee,
arm, or other body part than cerebral trauma. If mildly concussed, the odds
are that rapid recovery will ensue, although some data suggest that this
recovery can take longer. The effects of multiple mild insults were
unresolved by this study because the number of players sustaining multiple
concussions in the same season was not large enough to offer meaningful
evaluation.
Soccer
The frequency of soccer players "heading" a hard and fast-moving ball has
caused some concern regarding possible lasting effects of repeated mild head
trauma. Head injuries are believed to account for 4% to 22% of soccer
injuries. As with other sports, limited, but growing, mild concussion data
are available and the results are mixed. For example, no abnormalities were
found on neuroimaging (CT and MRI scans) or on a brief neuropsychological
battery administered to active and former professional soccer players
(Haglund & Eriksson, 1993). Mild EEG disturbances have been found in soccer
players, along with complaints of chronic postconcussive syndrome (Tysvaer,
Storli, & Bachen, 1989). Among studies finding more cognitive deficits, 69
active players and 37 former Norwegian soccer players were examined, and 30%
of the retired players complained of chronic postconcussive symptoms
(Tysvaer, 1992). One third of the former players displayed unexpected
cerebral atrophy on a CT scan. Eighty-one percent of former players were
found to have mild to moderate deficits on neuropsychological tests,
especially in the areas of memory, attention, concentration, and judgment,
as opposed to a 40% impairment rate in age-appropriate controls. As with
other studies, the inadequacies of a standard neurological examination for
detecting subtle cognitive changes were revealed, and screening through
neuropsychological assessment was recommended. Witol and Webbe (1994) also
suggested subtle cognitive dysfunction in collegiates associated with
repeated heading of a soccer ball. Further longitudinal research and control
for variables such as body contact and body-ground contact are necessary to
answer the question of soccer-related cognitive deficits.
Other Sports and Head Injuries
Surprisingly, the sport with the highest reported rate of head injuries is
horseback riding. One of the earliest examinations of equestrian head
injuries found five National Hunt Jockeys to have significant neurologic
impairment (Foster, Leiguarda, & Tilley, 1976). A review of medical records
of three Alberta, Canada hospitals indicated that 91% of all horseback
riding accidents involved a head injury. Although mild head injuries
dominated the clinical picture (83% of head injuries), 3% and 14%
respectively received moderate to severe injuries. The majority of accidents
were associated with falling or being thrown from a horse (Hamilton &
Tranmer, 1993). A study of pediatric equestrian head injuries found a
significantly lower rate of injury (3%-11%), perhaps because children wore
headgear more frequently than did adults (Bixby-Hammett, 1992).
The use of protective helmets is recommended in all sports in which a
possibility of head injury exists. Ice hockey officials currently report
that 3% to 7.5% of all reported injuries are concussions and these figures
have apparently declined over the years due to helmet use (Pelletier,
Montelpare, & Stark, 1993; Tegner & Lorentzon, 1991). Sports in which
helmets have not been adopted (i.e., rugby, Australian rules football, and
tae kwon do) report a 2% to 11% concussion rate, although the incidence of
minor concussions could be as high as 25% (Gibbs, 1993; O'Brien, 1992;
Seward, Orchard, Hazard, & Collinson, 1993; Zemper & Pieter, 1989).
Increased attention to safety features has reduced the rate of
automobile-racing-related head injuries, yet 10.5% of all hospitalizations
still involve head trauma. Competitive and recreational cycling also have
head injury rates up to 13.8% (Fullerton & Becker, 1991; Jordan, 1989).
Summary
It is difficult to reach general conclusions from the overall research on
mild head injury in sports regarding deficits, symptoms, recovery, and
outcome. This lack of consensus results because concussion depends on the
magnitude and direction of impact, the physical reaction and structural
features of the skull, and the position of the head at the moment of impact.
Hence, each impact can cause unique injuries (Jordan, 1989). The mixed
effects and recovery from mild head injury also depend on many individual
factors such as age, health, previous head injuries, intellectual reserve,
emotional status, and so on. Many studies suffer from methodological
problems, for example, failure to account for base rates of postconcussive
symptoms (e.g., Lees-Haley & Brown, 1993). In addition, attempting to
compare boxers who in some studies had an average education of approximately
8 to 9 years to higher achieving controls is a major confound.
For the majority of individuals, mild head injury in sports is rare and is
characterized by a brief loss or alteration of consciousness. Postconcussive
symptoms can result from mild concussion, although in most cases, there is
rapid recovery from these deficits. Considerable variability among group
data exists, and some individuals with complicated mild head injuries
experience symptoms for more than 1 year. In addition, the cumulative
effects of numerous mild head injuries are presently not well understood.
The amateur boxing literature suggests some ability of the brain to
withstand intermittent blows and manifest only minimal neurological or
neuropsychological deficits. When protections are lessened and the force and
number of blows increases, as in professional boxing or sparring with a
professional, the risks increase for greater brain dysfunction. It is hoped
that ongoing prospective research, such as Stewart and colleagues' study,
will clarify the long-term effects of repeated mild head injury in boxers.
Continued integration of functional neuroimaging methods and neuropsychology
will also contribute to better understanding of mild head trauma outcome.
Although many of the previously discussed studies of sports-related head
injuries have yielded inconclusive results, the use of professional and
amateur sports as a laboratory to study mild head injury should continue.
Professional and amateur sports remain arenas in which phenomena such as the
acceleration and deceleration forces commonly seen in automobile accidents
can be prospectively and innocuously examined. In addition, although mild
head injuries are infrequent and downplayed by athletes, the effects of
sports-related trauma have spurred the development of protective equipment
that has filtered into everyday life (e.g., bicycle helmets, automobile
design, etc.). Accordingly, the hope is that the number of head injuries in
the general public will decline. Ongoing study of this relatively small
sample of the population should reap continued benefits for society as a
whole.
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Mi faresti un enorme favore se mi dicessi dove scaricare tutte le medline
complete
Grazie di cuore
Coach