Just as an athlete recovering from a concussion needs to get physical rest, he needs cognitive (mental) rest as well, at least in the first few critical days after injury.
Because a concussion impacts the brain's cognitive function (those that involve thinking, concentrating, learning and reasoning), not its structure, it makes sense that engaging in cognitive activities (in other words, doing something that requires thinking or paying attention) is likely to make an athlete's concussion symptoms worse, and even delay recovery (although no link has been established to adverse long-term health effects).
As a result, recent concussion management guidelines, including the most recent international consensus statement of concussion experts ("Zurich consensus statement"), as well as guidelines issued by the American Academy of Pediatrics ,  the American Academy of Neurology,  the American College of Sports Medicine,  and the American Medical Society for Sports Medicine  all recommend that athletes limit scholastic and other cognitive activities, especially in the first several days after injury, to allow the brain time to heal.
While the Zurich consensus statement highlights the "concept of 'cognitive rest' ... with special reference to a child's need to limit exertion with activities of daily living that may exacerbate symptoms," including school, such recommendations are not without dissenters, most notably Christopher Randolph, PhD of the Department of Neurology at Loyola University Medical Center in Maywood, Illinois, who continue to question the idea that the rest needs to be "complete" and last until an athlete is entirely asymptomatic.
Writing in an editorial in the September 2012 issue of the Clinical Journal of Sports Medicine,  Randolph and his co-authors pointed to the lack of empirical data to that point in time showing that physical or cognitive activity after sport-related concussion exacerbated concussive injury, citing to studies of athletes suggested that re-engaging in activities in the days after injury was likely to have no detrimental effect or even a beneficial one; findings consistent with the view that total bed rest is generally contraindicated for most medical conditions.
Cognitive rest makes sense - in theory
A 2013 systematic review of the literature on the effects of rest and treatment following sport-related concussion  also took a somewhat cautious approach on cognitive rest, but one that leaned towards recommending cognitive rest in the first few days after concussion.
It noted that, while mental and physical rest in the initial days following a concussion have been strongly encouraged, and resting until symptom free widely recommended, there had been to that point only three published studies[9-11] evaluating the effects of cognitive rest in athletes who have suffered a sport-related concussion, and with specific reference to the Moser 2013 study,  noted the absence of a control or comparison group, "so that improvements could have been attributed to a diverse range of factors."
The authors acknowledged that the belief that rest was very likely beneficial following injury was "largely based on animal research, theory and expert consensus:" [4,11]
"First, concussions can have a large adverse effect on physical and cognitive functioning in the first few days postinjury, as the brain is in a state of metabolic crisis, [5,11] at which time increased energy demand may hinder the restorative process, and it is believed that rest might facilitate recovery."
"Second, in animal injury models, there appears to be a 'temporal window' of vulnerability in which a second overlapping injury results in greater levels of traumatic axonal injury and magnified cognitive and behavioral deficits. Thus, a rest period will reduce the likelihood of the athlete experieincing an overlapping injury."
"Finally, it has been demonstrated in rodent models that exercise appears to be good for the injured brain; however, animals that are allowed to exercise too soon after injury do not show the expected exercise-induced increases in molecular markers of neuroplasticity [the ability of the brain to rewire itself after injury]."
In the absence of further studies evaluating the effects of a resting period and the optimal duration of this period, the Zurich consensus statement thus recommended taking a "sensible approach involv[ing] a gradual return to school and social activities (prior to contact sports) in a manner that does not result in a significant exacerbation of symptoms." [1,4]
New empirical evidence supports cognitive rest recommendation
Since the Zurich consensus statement issued in March 2013, it has found important additional support in a 2014 study finding that teens who continue to engage in full cognitive activity after sport-related concussion take longer to recover than those who limit such activity, but that only those concussed athletes who engaged in the most cognitive activity experienced a significantly longer recovery as measured by the duration of concussion-related symptoms, while those who engaged in less cognitive activity - ranging from complete cognitive rest to significant, but reduced cognitive activity (see table below) - all recovered more quickly, but at about the same pace.
William P. Meehan, III, MD, Director of the Micheli Center for Sports Injury Prevention, MomsTEAM concussion expert emeritus, and a study co-author, noted that "While vigorous cognitive exertion appears detrimental to recovery, more moderate levels of cognitive exertion do not seem to prolong recovery substantially," findings which researchers said were similar to those in a 2008 study  finding that those who engaged in moderate levels of activity had better outcomes than those engaging in the highest and lowest levels of activity.
"This seems to suggest that while limiting cognitive activity is associated with a shorter duration of symptoms, complete abstinence from cognitive activity may be unnecessary," write Dr. Meehan and colleagues in the study.
Because the effect of cognitive rest may vary over time, such that cognitive activity may have more of an effect on recovery during its earlier phases, current concussion guidelines as well as the expert opinion of many clinicians involved in the assessment and management of sport-related concussion, including Dr. Meehan and Rosemarie Scolaro Moser, PhD, the author of a 2012 study showing the benefit of strict cognitive rest, and Director of the Concusssion Center of New Jersey, continue to recommend a period of near full cognitive rest in the first three to five days after injury, followed by a gradual return to cognitive activity, so long as it does not trigger a return of symptoms.
Post-concussion classroom accommodations
Once physical symptoms clear, but before exercise is allowed, a gradual return to a full academic day can begin, with classroom accommodations.
At the Lawrenceville School, a New Jersey prep school, for instance, a concussed athlete must stay in the infirmary on "strict rest in a darkened room with no iPod, no computer, and no reading" until his or her physical symptoms of concussion are at or close to their pre-injury baseline. At that point, he or she is gradually allowed to return to a full academic day, says former Medical Director, Dr. Robin Karpf.
"Their short-term memory and processing speed may continue to be off their baseline, but as long as they are not experiencing significant physical symptoms, I allow them back to the classroom with academic accommodations." (An e-mail is sent to all the athlete's teachers with information on the possible need for such accommodations).
"We need to do more to educate teachers that adjustments may need to be made for a concussed athlete," Dr. Karpf said. Kids who don't get cognitive rest, she has found, are more likely to have concussion symptoms that linger longer. If the increased cognitive challenges of the classroom bring about a recurrence of their physical symptoms, Dr. Karpf says, she returns them to rest. She does not start their gradual return to exercise or sports until they have returned to their neurocognitive baseline.
The approach taken at Lawrenceville is consistent with that recommended by the American Academy of Pediatrics in a 2013 clinical report recommending a gradual, symptom-limited, return to the classroom, a process now commonly called "return to learn."
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