- NEW YORK (Reuters
Health) - A mild blow to the head may cause more brain damage than previously
thought. California researchers have found that head injuries that cause
concussion can lead to changes that resemble brain damage in the comatose,
and these changes can last for weeks.
- The finding is important for athletes, especially those
in contact sports such as football and ice hockey, who may be at risk for
repeated concussions in short frames of time if they continue to play.
- ``We were very surprised,'' said Dr. Marvin Bergsneider
from the University of California, Los Angeles, lead author of the study
published in the Journal of Neurotrauma. ``It really defies standard physiology.''
- The researchers took positron emission tomography (PET)
scans that show glucose uptake indicating brain activity of 42 people who
had suffered mild head injuries such as concussion within the previous
month. Most of the head injuries were due to motor vehicle accidents or
falls. The results of the study showed that 84% of the patients (36) had
a reduction in the metabolic rate of glucose uptake in the brain.
- The investigators performed Glasgow Coma Scale (GCS)
tests on these study participants. The GCS assesses a person's ability
to answer simple questions, such as who and where they are, Bergsneider
explained. A level of 3 is deeply comatose, while 15 is the best score.
- The team found that 22 of the 36 patients had comatose-level
GCS scores (3 to 8). Of the 14 that had higher scores, six had initial
scores that were likely lower than 8 but had improved by the time of the
PET scan, Bergsneider said. These patients may have appeared to have mild
concussions but truly had more severe injury since small blood clots could
be detected on the scan, Bergsneider noted.
- It was remarkable that these people functioned as well
as they did with such low GCS scores, he said. ``They were awake'' and
able to answer simple questions, but had really intense testing been done,
``we would probably find deficits,'' Bergsneider said.
- It seems that the brain shuts off some functions in order
to heal, he suggested, although more research needs to be conducted to
confirm that this is what is happening. The changes in glucose use by the
brain seen on the PET resolved itself in all patients by the end of the
month, he noted.
- The significance of this finding lies in the fact that
many people, particularly athletes, suffer repeated concussions and may
be severely damaging their brain, Bergsneider told Reuters Health. Furthermore,
they often put themselves at risk by continuing to play after a period
of unconsciousness. Once the brain has been injured, it ``just can't respond
to another injury or insult.... There's not a lot of knowledge about this
vulnerability to a second concussion,'' he said. ''We're raising a little
alarm. This needs to be studied better.''
- SOURCE: Journal of Neurotrauma 2000;17:389-401.
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