The high incidence of concussions in contact sports and the risk of traumatic brain injury are a major cause for concern.
Setting new standards to protect your brain
The high incidence of concussions in contact sports and the risk
of traumatic brain injury are a major cause for concern. A new
review by researchers at The Montreal Neurological Institute and
Hospital – The Neuro, McGill University, MUHC, University of
Montreal, Toronto Rehabilitation Institute, and the University of
Toronto compares the latest research and assessment tests and
presents new clinical guidelines for the prevention, diagnosis,
treatment and return-to-play, to work or to school decisions for
concussed athletes.
There are 3 million sports-related concussions in the United
States each year and among people aged 15 to 24, concussions are
now second only to motor vehicle accidents as a leading cause of
traumatic brain injury (source: Center for Disease Control).
Ice-hockey is the sport with the highest risk for sustaining a
concussion (accounting for 20% of all injuries), followed by rugby,
football, and soccer. Symptoms of concussion include
dizziness, headaches, blurred or double vision, anxiety,
depression, attention deficits, memory problems, and psychomotor
slowing. These generally resolve within one week but in a
substantial proportion of athletes, they last longer than three
months.
Neuropsychological tests that take into account injury variables
such as number of previous concussions and symptoms lack
sensitivity for detecting changes in brain function and/or guiding
return-to-play decisions. New techniques, such as ERP (event
related potential) and functional MRI, are now proving to be more
sensitive than behavioural testing to detect brain dysfunctions
following a concussion. These tests assess the activity of
neurons involved in cognitive and behavioral tasks. ERP uses
electroencephalography (EEG), a non-invasive technique, to record
the electrical activity of a group of neurons in a particular brain
region associated with a cognitive task. fMRI measures the changes
in blood oxygenation related to nerve cell activity in a given
cerebral region during a cognitive task.
“ERP and fMRI provide sensitive markers of early and late brain
dysfunction following sports concussion, says Dr. Alain Ptito,
neuropsychologist at The Neuro and lead investigator. “Until
now the absence of symptoms for a few days and normal
neuropsychological performance were considered to reflect complete
brain recovery. In fact, the changes observed in ERP and fMRI are
found not only in the acute phase (i.e. less than three months)
after concussion, but sometimes several weeks or even years after,
suggesting that the dysfunction, though qualified as mild, may
persist. This indicates that absence of symptoms is not necessarily
an absolute marker of complete brain recovery.”
These findings have important clinical implications; although
symptoms have to guide return-to-play decisions, objective measures
should be considered for better management. Return-to-play
decisions are extremely important because unresolved post
concussion symptoms increase the risk for further and more severe
concussions as well as prolonged symptoms.
ERPs and fMRI can significantly contribute to understanding the
consequences of sports concussion on brain functions and they can
help in assessing the extent of recovery and contribute to
return-to-play decisions. It is hoped that further studies
investigating clinical correlates of ERPs and fMRI will be carried
out so that these techniques can become routinely integrated in
concussion assessment. The review was published in The Physician
and Sportsmedicine USA.
About the Montreal Neurological Institute and
Hospital
The Montreal Neurological Institute and Hospital — The Neuro, is
a unique academic medical centre dedicated to neuroscience. The
Neuro is a research and teaching institute of McGill University and
forms the basis for the Neuroscience Mission of the McGill
University Health Centre. Founded in 1934 by the renowned Dr.
Wilder Penfield, The Neuro is recognized internationally for
integrating research, compassionate patient care and advanced
training, all key to advances in science and medicine. Neuro
researchers are world leaders in cellular and molecular
neuroscience, brain imaging, cognitive neuroscience and the study
and treatment of epilepsy, multiple sclerosis and neuromuscular
disorders. The Montreal Neurological Institute was named as one of
the Seven Centres of Excellence in Budget 2007, which provided the
MNI with $15 million in funding to support its research and
commercialization activities related to neurological disease and
neuroscience.