Multiple mild concussions have a cumulative, lasting effect
(Medical Xpress) -- Repeated concussions, even mild ones, can result in profound problems with learning and memory, suggests a study led by William Meehan, MD, director of the Sports Concussion Clinic at Boston Childrens Hospital, and Michael Whalen, MD, director of the Acute Brain Injury Laboratory at MassGeneral Hospital for Children. Using a mouse model, the study documents cumulative, long-lasting impairment of brain function after repeated mild concussions, especially when they occur in close succession.
The study, conducted at Massachusetts General Hospital, also suggests that the more time allowed for recovery between concussions, the lower the likelihood of long-term impairment of brain function. Results appear in the journal Neurosurgery (online June 27).
According to Meehan and Whalen, the findings support the practice of keeping concussed athletes out of play until they recover. Our model showed that even concussions that individually have no demonstrable effect on brain function can have profound detrimental effects if repeated, especially multiple times at close intervals, says Meehan, first author on the paper and also director of research for the Brain Injury Center at Boston Childrens.
Meehan, Whalen and colleagues at Massachusetts General Hospital compared cognitive function in a total of 156 mice that sustained different numbers of mild concussions (while under anesthesia to avoid pain at the time of injury) at different time intervals. To test cognitive function, they had the mice swim through a Morris water maze and find a hidden platform using spatial memory.
After a single concussion, injured mice performed as well as uninjured control mice (which were also anesthetized) in the maze.
After three concussions, the injured mice performed worse than controls; this became markedly worse after five concussions.
When mice sustained a series of five concussions, they performed worse than controls when the concussions were one day or one week apart. But when concussions were one month apart, they performed just as well after the fifth concussion as the uninjured mice.
Concussions sustained at short time intervals had long-term effects: Even after a month-long recovery period, mice that sustained a total of five concussions at daily and weekly intervals continued to perform worse than uninjured mice. One year later, those sustaining concussions just a day apart still performed worse than controls.
Concussion is a disturbance of normal brain function that results from rapid rotational acceleration of the brain. While there is no visible structural injury (no bleeding, swelling or visible changes on CT or MRI), cognitive effects are immediate and can include blunted reaction time, slowed thinking and difficulty learning. If there is no further injury and athletes are allowed both physical and cognitive rest, most will recover on their own over time.
We found that there is a vulnerable time frame in which multiple concussions, even if they are mild, can cause long-term and likely permanent cognitive deficits, says Meehan. Our findings support the idea that athletes should be allowed time for full recovery after a concussion before returning to play. They need to have protected rest time.
A critical question that remains unanswered, however, is exactly how much rest time an individual player needs between concussions to avoid long-term effects on cognition, says Whalen, the papers senior author. This safe rest time is likely related to concussion severity, number, and genetic makeup of the individual.
Previous published studies suggest that younger athleteshigh school as compared with college athletes, for examplemay be slower to recover from concussion.
Provided by Children's Hospital Boston
- Pro-bowler suicide raises questions of early concussion detection May 07, 2012 | not rated yet | 0
- NY to require benching students with concussions Sep 30, 2011 | not rated yet | 0
- Concussed high school athletes who receive neuropsychological testing sidelined longer Dec 15, 2010 | not rated yet | 0
- Female and younger athletes take longer to overcome concussions May 08, 2012 | not rated yet | 0
- Ban bodychecking in youth hockey to prevent concussions Apr 18, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
(AP)—Alabama health officials say a mysterious respiratory illness has left five people hospitalized and two dead in the southeastern part of the state.
Diseases, Conditions, Syndromes 11 minutes ago | not rated yet | 0
A paper recently published in the New England Journal of Medicine and co-written by physicians and scientists at the University of Colorado School of Medicine finds that an important genetic risk factor for pulmonary fibros ...
Diseases, Conditions, Syndromes 13 hours ago | not rated yet | 0
Using the Department of Defense Serum Repository (DoDSR), University of Cincinnati (UC) researchers have identified a number of biomarkers for inflammatory bowel disease (IBD), which could help with earlier diagnosis and ...
Diseases, Conditions, Syndromes 13 hours ago | 5 / 5 (1) | 0
(HealthDay)—Three-quarters of public schools in the metro Atlanta area contain microbes, including bacteria indicating the presence of fecal matter, according to research published in the May 17 issue of ...
Diseases, Conditions, Syndromes 14 hours ago | not rated yet | 0
(HealthDay)—Factors such as increased case finding may explain why Michigan had half of the total spinal infections associated with contaminated methylprednisolone acetate in the recent fungal meningitis ...
Diseases, Conditions, Syndromes 15 hours ago | not rated yet | 0
Italian lawmakers on Wednesday gave their final approval to a law that allows limited use of a controversial type of stem cell therapy which has been condemned by many scientists but has given hope to families of terminally-ill ...
1 minute ago | not rated yet | 0
(AP)—The mayor of Portland, Ore., has conceded defeat in an effort to add fluoride to the city's drinking water.
30 minutes ago | not rated yet | 0
Is it permissible to harm one to save many? Those who tend to say "yes" when faced with this classic dilemma are likely to be deficient in a specific kind of empathy, according to a report published in the scientific journal ...
2 hours ago | not rated yet | 0 |
Phthalates: Study links chemicals widely found in plastics, processed food to elevated blood pressure in children, teens
Plastic additives known as phthalates (pronounced THAL-ates) are odorless, colorless and just about everywhere: They turn up in flooring, plastic cups, beach balls, plastic wrap, intravenous tubing and—according to the ...
3 hours ago | not rated yet | 1 |
(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...
19 hours ago | 4.2 / 5 (5) | 0 |