UPDATED
Because a concussion impacts the brain's cognitive functions (those that involve thinking, concentrating, learning and reasoning), the four most recent concussion guidelines, [1,2,9-11] a number of recent studies,[3,12, 13, 16, 17, 18] and the expert opinions of many clinicians involved in the assessment and management of sport-related concussion, recommend cognitive rest in the immediate period after injury to allow the brain time to heal and speed recovery.
An athlete should avoid strenuous activity until the athlete has no post-concussion symptoms at rest because physical activity may make symptoms worse and has the potential to delay recovery. While strict bed rest is not necessary, and while the effect of physical activity on concussion recovery has not been extensively studied (indeed, there is some evidence to suggest that mild physical exertion may actually help concussion recovery, especially for those suffering from post-concussion syndrome [1]), the consensus of experts recommends broad restrictions on physical activity in the first few days after a concussion, including:
Just as an athlete recovering from a concussion needs to get physical rest, he needs cognitive (mental) rest as well.
Because a concussion impacts the brain's cognitive function (those that involve thinking, concentrating, learning and reasoning), not its structure, engaging in cognitive activities (in other words, engaging in activities that requires a great deal of thinking or paying concentrated attention) may make an athlete's concussion symptoms worse, and, as a 2014 study[12] (discussed in greater detail below) finds, lengthy recovery time by from 2 to 5 times.
As a result, many experts recommend that concussed student-athletes limit scholastic and other cognitive activities, at least in the first several days after concussion, to allow the brain time to heal.
Cognitive rest means:
The concept of cognitive rest was introduced at the Second International Conference on Concussion in Sport held in Prague in 2004.[14] The Prague statement recognized cognitive rest as a "need to limit exertion with activities of daily living and to limit scholastic activities while symptomatic," and went on to state that, "During this period of recovery in the first few days after an injury, it is important to emphasize to the athlete that physical and cognitive rest is required. Activities that require concentration and attention may exacerbate the symptoms and as a result delay recovery."
At conferences in Zurich in 2008 and 2012, and the respective consensus statements issued shortly thereafter, [1,15] the concept of cognitive rest was reinforced, with physical and cognitive rest being described in both statements as the "cornerstone" of concussion management.
A 2013 systematic review of the literature on the effects of rest and treatment following sport-related concussion [7] 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 [3,13,16] evaluating the effects of rest in athletes who have suffered a sport-related concussion, and with specific reference to the Moser study [3], stated the absence of a control or comparison group, "so that improvements could have been attributed to a diverse range of factors."
"For these reasons," the study 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 post-injury, as the brain is in a state of metabolic crisis, [4] at which time increased energy demand [for a chemical in the brain called adenosine phosphate (ATP)] may hinder the restorative process, and it is believed that rest might facilitate recovery.[8]
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 experiencing 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]. For these reasons, it is believed that rest is very likely beneficial following injury. However, this is largely based on animal research, theory and expert consensus." [7]
The number of studies supporting the current consensus opinion that limiting extensive cognitive activity reduces the duration of concussion symptoms has, however, been growing.
In a 2012 study of concussed high school students published in the Journal of Pediatrics, [3] researchers - led by MomsTeam concussion expert neuropsychologist Rosemarie Scolaro Moser, PhD [2] - found that, after one week of strict cognitive and physical rest, concussed athletes scored significantly better on the ImPACT neurocognitive test [3] and reported statistically significant decreases in the number and severity of post- [4]concussion symptoms [4].
Perhaps surprisingly, the beneficial effects of the week of rest were seen whether the rest came soon after a concussion or weeks to months later. Indeed, more than a quarter of the group which continued to experience concussion symptoms past the 31-day mark (defined by some as the point at which a diagnosis of post-concussion syndrome [1] is appropriate) still demonstrated improvements with prescribed rest comparable to those experienced by concussed athletes in the study who were still in the early stages of concussion recovery.
"Our results represent the first data documenting the efficacy of prescribed rest for the treatment of post-concussion symptoms and cognitive dysfunction, whether the rest is applied in the early or prolonged stages of recovery," Moser observed. The idea that cognitive and physical rest may help improve the condition of patients with post-concussion syndrome [1] is [also] noteworthy," she writes, because "there may be a perception among clinicians that once the 7- to 10-day time period in which the neurometabolic "cascade" [4] has passed, and a patient continues to experience concussive symptoms, cognitive and physical rest is of limited use."
"Without evidence to support the case for rest, especially when weeks or months have passed since the injury, clinicians are met with resistance from athletes, parents, and school and athletic officials who do not see the therapeutic value of missing school or sports when many weeks have already passed," Moser's 2012 study notes. "Athletes, parents, and coaches may balk at the need for, or effectiveness of, rest and inactivity. Without supportive empirical data, patient compliance is threatened and clinician judgments are often challenged and threatened," says Dr. Moser.
Commenting on the finding that even delayed cognitive rest may be beneficial, William P. Meehan, III, MD, former Director of the Sports Concussion Clinic in the Division of Sports Medicine at Boston Children's Hospital and Director of the Micheli Center for Sports Injury Prevention, says that the practice in his clinic has been "always to initiate [cognitive rest], even late in the course [of treatment], if it had not been attempted already." He thus found Dr. Moser's conclusions "reassuring."
"Our research now provides clinicians with solid evidence to show athletes, parents, schools and teams that rest really helps and should not be underestimated, no matter how long the time from injury," says Moser. "I hope it helps us debunk the mistaken philosophy that it is better to push through the pain, than to take the time to heal."
In a second study, published online ahead of print in October 2014 in the journal Brain Injury [17], Dr. Moser sought to replicate and extend her first study, while attempting to control for spontaneous recovery (because there was only a single follow-up period for the athletes in her earlier study, the number who had sustained improvement, recovery and return to their normal lives spontaneously with prescribed rest was unknown).
To do that she studied a small group of thirteen youth athletes who (i) were diagnosed at their school or another facility as having sustained a concussion and had undergone post-concussion testing there, (ii) either were not encouraged to rest following their injury, or did not follow their doctor's orders to rest, and (iii) were later referred for clinical assessment and treatment because they were continuing to experience concussion symptoms.
"Because you can't tell one group of concussed athletes to rest and the other group to not rest but to continue playing in contact sports while they are symptomatic", noted Dr. Moser, the study's design fortuitously allowed the athletes "in a sense [to] serve as their own controls," because they themselves had not rested initially.
Based on the results of her earlier study, Dr. Moser and her colleagues anticipated that the athletes would show significant improvement on neurocognitive testing and self-reporting of concussion-related symptoms after engaging in a week of comprehensive rest (which did not mean bed rest, time spent in a dark room (e.g. so-called "cocoon therapy"), or socially isolation, but did involve staying home from school and avoiding exercise and mentally/physically stimulating activities for 1 week, which represented a major change in their lifestyle).
As in the earlier study, Dr. Moser and her colleagues found that symptoms improved following rest in 54% overall and in 87% of those who had elevated total scores on a post-concussion symptom scale [5] before being prescribed rest. Three-quarters of patients showed statistically reliable improvement in scores on one or more tests of neurocognitive function and four of the thirteen (31%) showed reliable improvements on two or more cognitive domain scores. If reliable improvement on two or more cognitive test scores or improved symptoms scores was used as a measure for improvement, then 61% had evidence of improvement following prescribed rest.
What factors led to the athletes' improvement in cognitive function and symptoms after prescribed rest is still unknown, says Dr. Moser. She noted that the athletes in the study were not typical of the general population, as nearly half had a pre-existing neurodevelopmental problem such as ADHD [6] or learning disability and half reported a history of two prior concussions [7], both of which previous studies have found to be complicating factors [8] for concussion recovery. Thus she cautioned against generalizing her findings to adolescent athletes without these pre-injury risk factors for longer recovery.
Other factors may also have contributed to the athletes' improvement. Previous studies on mild traumatic brain injury and mental health treatment suggest that some of the improvement may have been the result of (i) education and reassurance provided at the specialty clinic;(ii) non-specific treatment effects (clinician effects, other unmeasured effects); and (iii) placebo effects.
"Given that many adolescents and young adults have stressful and pressured daily lives," Dr. Moser and her colleagues wrote, "it is suspected that being completely ‘unplugged' from all their activities (and much of their stressors) for a few days and getting much more sleep and rest than usual, at least in part, drove the improvements." "In addition, being optimistic that rest would improve their condition may have been another factor in improvement (although it is not uncommon for adolescents to be initially doubtful and resistant to foregoing school and friends for a week)."
"Unfortunately, there is ... much push back to the idea of resting after a concussion because we live such outrageously hurried, busy lives that are technologically and electronically bombarded each day," said Dr. Moser in an email interview. "Years ago, there were no computers, no video games, no cell phones, no texting. TV had a limited number of channels in black and white that were not on 24 hours a day. Moms were not sports taxis and kids stayed home after school and on weekends. Homework was reasonable, and missing school was not perceived as jeopardizing your chances of getting into Harvard. 'Friday Night Tykes' did not exist. We rested on Sundays and lived 'unplugged' lives. Brains had time to rest and recover naturally."
"While the study has limitations, which the authors lay out nicely in the paper, this study does certainly highlight the importance of guided and supervised rest in the recovery process following concussion," said Dr. Johna Register-Mihalik, an assistant professor of Exercise and Sport Science and member of the faculty at the Matthew Gfeller Sport-Related TBI Research Center at the University of North Carolina at Chapel Hill, who was not involved in the study. " Future research should build off of studies such as this to include prospective designs across multiple study sites, adequate control groups and additional, perhaps functional outcome measures."
"There is still so much we don't know about the use of rest for concussion treatment," said Dr. Moser, including how much rest, what kind of rest, who benefits from rest, when should exercise be introduced, and what are the emotional consequences of rest. But, she said, one thing seems to be "a no-brainer: rest is a good thing."
At least some of the questions about how much rest were addressed in two recent studies, first a 2014 study [9] co-authored by Dr. Meehan and published in the journal Pediatrics [12] which found that teens who continue to engage in full cognitive activity in the period just after sport-related concussion take longer to recover than those who limit such activity in the first 7 to 10 days after injury.
Perhaps surprisingly, Dr. Meehan and his colleagues found that only those concussed athletes who continued to engage in full cognitive activity experienced a significantly longer recovery as measured by the duration of concussion-related symptoms, and that those who limited cognitive activity - ranging from complete cognitive rest to significant, but reduced cognitive activity (see table below) - all recovered at about the same pace.
"While vigorous cognitive exertion appears detrimental to recovery, more moderate levels of cognitive exertion do not seem to prolong recovery substantially," wrote Dr. Meehan, findings similar to those in an earlier study, [13] which found 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," says Dr. Meehan.
Because the effect of cognitive rest may vary over time, such that cognitive activity has more of an adverse effect on recovery during the 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 Drs. Meehan and Moser, recommend a period of near full cognitive rest in the first days after injury, followed by a gradual return to cognitive activity, so long as it does not trigger a return of symptoms.
Indeed, recent research [10] [5] which suggests that blood flow to the brain is still reduced in more than a third of 11- to 15-year-olds even at 1 month or more post-concussion, Dr. Moser argues, not only "supports an even longer recovery period than typically thought, but is consistent with the notion that a period of rest may be therapeutic" in treating post-concussion syndrome [1].
0 |
Complete cognitive rest | No reading, homework, text messaging, video game playing,online activity, crossword puzzles, or similar activities. The most stimulating activities at this level would be watching television, watching movies, or listening to music. |
1 | Minimal cognitive activity | No reading, homework, crossword puzzles, or similar activities.Less than 5 text messages per day, less than 20 min per day combined of online activity and video games. |
2 | Moderate cognitive activity | Reading less than 10 pages per day, less than 20 text messages per day, and doing less than 1 hr combined of homework, online activity, and video games per day. |
3 | Significant cognitive activity | Reading less, doing less homework, working less online, text messaging less, and doing crossword or other activities thanyou would normally do, but more than listed in level 2. |
4 | Full cognitive activity | You have not limited cognitive activity at all. |
*Patients were told that cognitive activities are "those activities which require you to think harder than usual. Homework, reading, playing video games, text messaging, doing crossword puzzles, playing trivia games and working online are all forms of cognitive activity." |
But while a growing body of evidence, consensus guidelines, and the expert opinion of clinicians such as Drs. Moser and Meehan supports limiting extensive cognitive activity in order to reduce duration of concussion symptoms, such recommendations are not without dissenters, and, indeed, a more recent study on the effect of strict physical and cognitive rest, published in January 2015 in the journal Pediatrics, [18] appears to support the view, also expressed by some clinicians and other experts, [19] that there may be no advantage to strict rest, beyond the first 1 to 2 days after injury.
Christopher Randolph, PhD of the Department of Neurology at Loyola University Medical Center in Maywood, Illinois, is one who continues 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, [6] Randolph and his co-authors pointed to the lack of empirical data to show that physical or cognitive rest after sport-related concussion exacerbated concussive injury, citing to studies of athletes suggesting that re-engaging in activities in the days after injury is 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. (although it is important to note that he made his comments before the 2014 Brown study that appears to show that athletes who continue to engage in full cognitive activity after concussion take longer to recover than those who limit such activity)
A 2013 clinical report by the American Academy of Pediatrics [8] likewise noted a lack of research documenting the benefits or harm of strict cognitive rest in either prolonging concussion symptoms or the ultimate outcome for the student following a concussion. The AAP even went so far as to state that, given the disruptive nature that concussion symptoms may pose for the student and his or her family, "adding additional restrictions that may not be needed has the potential to create further emotional stress during the recovery."
In the most recent study,[18] researchers at the Medical College of Wisconsin reported that strict physical and cognitive rest in the five days immediately after concussion, in fact, did not help teens recover more quickly than taking it easy for one to two days after injury and then returning to school.
Indeed, the group advised to rest for five days actually reported more daily post-concussive symptoms [5] during the first 10 days after their emergency department visit and slower resolution of symptoms than those who rested for 1 to 2 days and then returned to school.
The study was unable to explain the difference in symptom reporting, but noted that it was possible that the discharge instructions influenced the patient's' perception of illness, leading them to report more symptoms, and that the deleterious effects of strict rest they observed may have more to do with emotional distress caused by school activity and activity restriction, because missing social interactions and falling behind academically may cause concussed student-athletes to become depressed, increasing physical and emotional symptoms, just as the AAP predicted four years earlier in its 2010 clinical report[8] when it suggested that, "adding additional restrictions that may not be needed" had the "potential to create further emotional stress during the recovery."
Indeed, support appears to be growing among concussion clinicians and researchers for the view that prolonged rest may not be the best treatment for concussion. Most recently, a group of concussion experts, including Dr. Meehan, reported [11], [20] after meeting in October 2015 at a conference at the University of Pittsburgh Medical Center sponsored by the National Football League and closed to the press, that strict rest beyond the first few days after a concussion might actually delay recovery.
"Exercise is a way of treating this," Dr. Javier Cardenas, a neurologist at the Barrow Concussion and Brain Injury Center in Arizona, told the Pittsburgh Post-Gazette [12]. "Many times, we see patients who are completely restricted from any physical activity. As one of the major sources of this injury is sports and athletics, for those who are involved in athletics, this is actually a punishment. They become depressed. They become anxious. So allowing them to participate in physical activity - while keeping them out of harms' way, of course - is actually a rehabilitation method."
Another concussion expert who believes that complete cognitive rest may be over-prescribed is Elizabeth M. Pieroth, Pys. D., a clinical neuropsychologist with North Shore Medical Group in Chicago and a consultant to a number of Chicago professional sports teams, including the Bears, and an unpaid consultant to the National Football League.
Like Dr. Cardenas, in a recent video, Dr. Pieroth saw many of the same downsides to keeping concussed athletes out of school for more than a few days after injury, including social isolation, depression, and an unhealthy focus on symptoms instead of recovery:
If there is one thing on which clinicians and researchers alike agree it is this: that additional research is needed to determine how the effect of cognitive activity changes over time. In the absence of more data to establish the optimal level and duration of cognitive rest, most experts continue to recommend 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." [1,7,8,12,18,19]
This is the approach recommended by the authors of the 2014 and 2015 studies in Pediatrics,[12,18] whose findings taken together suggest that, while limiting cognitive activity is associated with a shorter duration of symptoms, a complete and extended abstinence from cognitive activity may be unnecessary, and possibly counter-productive.
This is also the approach recommended by the AAP in its 2013 clinical report on return to learning [13],[8] in which the pediatrics group calls for an "individualized approach for the student when a pediatrician is making recommendations for cognitive rest and the student's RTL [return to learning] in the school setting."
"Determining the appropriate balance between how much cognitive exertion and rest is needed is the hallmark of the management plan during cognitive recovery," says the APP.
Reviewing the results of the pediatric studies demonstrating an association with rest and outcome after concussion, the studies, taken together, showed that the "current usual care endorsing modest physical and cognitive rest after injury is an effective strategy for recovery."[18]
1. McCrory P, Meeuwisse W, Audry M, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. Br. J. Sports Med. 2013:47:250-258.
2. Halstead, M, Walter, K. Clinical Report - Sport-Related Concussion in Children and Adolescents. Pediatrics 2010;126(3):597-615.
3. Moser RS, Glatts C, Schatz P. Efficacy of Immediate and Delayed Cognitive and Physical Rest for Treatment of Sport-Related Concussion. J Pediatrics 2012;161(5):922-926.
4. Giza CC, Hovda DA, The Neurometabolic Cascade of Concussion. J. Ath Train 2001;36(3):228-235. [14]
5. Maugans TA, Farley C, Altay M, Leach J, Cecil KM. Pediatric sports-related concussion produces cerebral blood flow alterations. Pediatrics 2011;129:28-37.
6. Kirkwood MW, Randolph C, Yeates KO. Sport-Related Concussion: A Call for Evidence and Perspective Amidst the Alarms. Clin J Sports Med 2012;22(5):383-384.
7. Schneider K, Iverson G, Emery C, McCrory P, Herring S, Meeuwisse W. The effects of rest and treatment following sport-related concussion: a systematic review of the literature. Br J Sports Med 2013;47:304-307.
8. Halstead ME, et al. Clinical Report: Returning to Learning Following a Concussion. Pediatrics doi:10.1542/peds.2013-2867 (epub October 27, 2013).
9. Harmon KG, Drezner J, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. 2013;47:15-26.
10. Giza C, Kutcher J, Ashwal S, et. al. Summary of evidence-based guideline update: Evaluation and management of concussion in sports: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2013;80(24):2250-2257 DOI:10.1212/WNL.ob013e31828d57dd.
11. Herring SA, Cantu RC, Guskiewicz KM, et al. American College of Sports Medicine Concussion (mild traumatic brain injury) and the team physician: a consensus statement-2011 update. Med Sci Sports Exerc. 2011;43(12):2412-2422.
12. Brown NJ, Mannix RC, O'Brien MJ, Gostine D, Collins MW, Meehan WP. Effect of Cognitive Activity Level on Duration of Post-Concussion Symptoms.Pediatrics 2014;133(2):1-6.
13. Majerske CW, Mihalik JP, Ren D, et al. Concussion in sport: postconcussive activity levels, symptoms, and neurcognitive performance. J Athl Tr. 2008;43(3):265-274.
14. McCrory P, Johnston K, Meeuwise W, et al, Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Br J Sports Med. 2005;39(4):196-204.
15. McCrory P, Meeuwise W, Johnston K, et al. Consensus statement on concussion in sport: the 3rd International Conference on Concussion in Sport held in Zurich, November 2008. J Athl Tr. 2009;44(4):434-448.
16. Gibson S, Nigrovic LE, O'Brien M, Meehan WP, The effect of recommending cognitive rest on recovery from sport-related concussion. Brain Inj. 2013;27(7-8):839-842.
17. Moser R, Schatz P, Glenn M, Kollias K, Iverson G. Examining prescribed rest as treatment for adolescents who are slow to recover from concussion. Brain Inj. 2014; Early Online: 1-6 DOI: 10.3109/02699052.2014.964771 (e-published ahead of print October 1, 2014)
18. Thomas DG, Apps JN, Hoffman RG, McCrea M, Hammeke T. Benefits of Strict Rest After Acute Concussion: A Randomized Controlled Trial. Pediatrics 2015;135(2). DOI:10.1542/peds2014-0966 (e-published ahead of print, January 5, 2015).
19. Catherine Saint-Louis. "Limiting Rest Is Found To Help Young Concussion Patients." New York Times Jan. 5, 2015. http://www.nytimes.com/2015/01/05/us/limiting-rest-is-found-to-help-youn... [15] (most recently accessed, January 11, 2015)
20. Mike Florio. "Concussion conference suggests that rest may not be the best treatmen.t" NBC Sports Pro Football Talk. October 17, 2015 (accessed November 3, 2015 at http://profootballtalk.nbcsports.com/2015/10/17/concussion-conference-su... [11])
Updated and revised December 15, 2015
Links:
[1] https://momsteam.com/node/3310
[2] https://momsteam.com/node/3468
[3] https://momsteam.com/node/801
[4] https://momsteam.com/node/149
[5] https://momsteam.com/health-safety/concussion-signs-and-symptoms-physical-cognitive-emotional-sleep-related
[6] https://momsteam.com/health-safety/should-kids-with-adhd-avoid-contact-sports
[7] https://momsteam.com/health-safety/multiple-concussion-history-recent-concussion-increase-risk-longer-recovery
[8] https://momsteam.com/health-safety/concussion-evaluation-management-return-to-play-decision-involves-many-factors
[9] https://momsteam.com/node/7003
[10] https://momsteam.com/node/4147
[11] http://profootballtalk.nbcsports.com/2015/10/17/concussion-conference-suggests-that-rest-may-not-be-the-best-treatment/
[12] http://www.post-gazette.com/sports/steelers/2015/10/17/Rest-not-best-for-concussion-recovery-experts-conclude-during-UPMC-Concussion-Conference/stories/201510170048
[13] https://momsteam.com/node/6780
[14] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC155411/
[15] http://www.nytimes.com/2015/01/05/us/limiting-rest-is-found-to-help-young-concussion-patients.html?_r=0
[16] https://momsteam.com/cognitive-rest/new-study-shows-benefit-cognitive-physical-rest-in-concussion-recovery
[17] https://momsteam.com/strict-rest-after-concussion-does-not-improve-recovery-new-study-finds
[18] https://momsteam.com/cognitive-rest/full-cognitive-activity-after-concussion-delays-recovery-study-finds
[19] https://momsteam.com/health-safety/neuropsychologist-should-help-plan-academic-accommodations-after-concussion
[20] https://momsteam.com/academic/post-concussion-strategies-for-the-classroom
[21] https://momsteam.com/memory/recovering-from-concussion-teachers-play-important-role
[22] https://momsteam.com/health-safety/parents-critical-participants-in-recognition-treatment-recovery-concussion
[23] https://momsteam.com/pcss/teens-with-multiple-concussion-history-much-more-likely-report-continuing-symptoms
[24] https://momsteam.com/health-safety/return-to-play/concussion-return-to-play-step-by-step-approach-recommended