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Full Cognitive Activity After Concussion Delays Recovery, Study Finds

Take 2 to 5 times longer to recover than those who limit cognitive activity after concussion

Teens who continue to engage in full cognitive activity after sport-related concussion take from two to five times longer to recover on average than those who limit such activity, says a 2014 study.[1]

Researchers found that those who engaged in the most cognitive activity after concussion took approximately 100 days on average to recover from their symptoms compared to approximately 20 to 50 days for patients who limited cognitive exertion.

Boy playing on laptop computer

Significantly, researchers from Boston Children's Hospital, Children's Hospital of Philadelphia and the University of Pittsburgh Medical Center found 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 - and that those who engaged in less cognitive activity - ranging from complete cognitive rest to moderate cognitive rest (see table below) - all recovered at about the same pace.

The findings, published online in the journal Pediatrics provide important support for current concussion guidelines [2-6] recommending cognitive rest during the initial stages of recovery from concussion, and add to a small but growing body of empirical evidence demonstrating the benefits of such rest for children and adolescents. [7,8]  

"While vigorous cognitive exertion appears detrimental to recovery, more moderate levels of cognitive exertion do not seem to prolong recovery substantially," said William P. Meehan, III, MD, Director of the Sports Concussion Clinic at Boston Children's Hospital and one of the study's authors, similar to those in a 2008 study [7] which found that those who engaged in moderate levels of activity after concussion 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," said Dr. Meehan. 

Researchers suggested that cognitive activity may have more of an effect on recovery in the period immediately after injury, and said additional research would be needed to determine how the effect of cognitive activity changes over time.

Current concussion guidelines [2-6], 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, Director of the Concusssion Center of New Jersey and the author of a 2012 study showing the benefit of strict cognitive rest [8], who was not involved in the current study), 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. 

"For the first three to five days, we tell our patients with concussions that they should really aim to be at a zero level or complete cognitive rest," said Meehan in an interview with the Boston Globe.  [11] That means no reading, homework, text messaging, or video game playing; basically, it's fine to lie in bed quietly, watching TV or listening to music with the volume on low. Those experiencing severe symptoms may prefer to be resting anyway," he said, "but those with mild symptoms may think they can go back to school or resume exercise right away, which may delay their recovery."

After a few days, kids can slowly add mental activities such as doing a crossword puzzle or sending a few text messages to see how they feel. "If symptoms exacerbate, they should go back to resting," Meehan said. If they're feeling OK, they can continue to
gradually add mental challenges, resuming some school work on a lighter schedule. Throughout, they should continue to assess their symptoms and cut back if the headaches or dizziness return. 

Important first step in concussion recovery 

The study also provides data to support the practice of putting academic accommodations [9,10] in place for student-athletes suffering sport-related concussions to allow for relative cognitive rest in a school setting, an important first step in the management of concussion. "Given our findings, it is likely that academic accomodations can speed the recovery process," the study says.

Neal McGrath, PhD, Director of the Sports Concussion Center New England, who was not involved in the study, said it "provides important findings that help more firmly establish what clinicians who work with concussion patients see on a daily basis: sufficient cognitive rest is crucial, both in getting recovery on track in the early days post-injury and in facilitating recovery as students re-engage with academic challenges and information processing demands in their everyday lives."  

Dr. McGrath, the author of a seminal 2010 article in the Journal of Athletic Training on supporting the student-athlete's return to the classroom after a sport related concussion,[10] said that, "the data provide the most sophisticated glimpse yet of a phenomenon that has been easy to describe clinically but hard to quantify. The study's average duration of symptoms - 43 days - reminds us as well that concussion recovery is a process that often takes considerable time in the life of a young person."

Study details 

Researchers obtained data from 335 participants seen at the Sports Concussion Clinic at Boston Children's Hospital within 3 weeks of diagnosed concussion.  

  • Patients ranged from age 8 to 23 with a mean age of 15 ± 2.6 years;
  • 39% reported at least 1 previous concussion
  • 19% reported a loss of conciousness at the time of injury
  • 37% reported amnesia.  
  • Most concussions occurred while playing ice hockey, American football, basketball and soccer.

At intake and each follow-up visit, study participants were instructed to (a) rate the severity of symptoms that started at the time of their concussion and that they were still experiencing within 24 hours of their clinic visit using the PCSS, a 22-item post-concussion symptom scale included in the Sport Concussion Assessment Tool version 2 (SCAT2); (b) record the date they last had concussion symptoms in the event they were symptom-free; and (c) estimate their average level of cognitive activity in which they had participated since their last visit using the following scale developed by 2 clinician-researchers experienced in concussion management.  Cognitive-activity days were then calculated by multiplying the average cognitive activity level reported by the patient by the days between visit.

 Cognitive Activity Scale
 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 hour 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 less than you would normally do, but more than listed at level 2.
4 Full cognitive a activity   You have not limited cognitive activity at all.


Athletes were considered recovered when (1) they were symptom-free at rest; (2) they were symptom-free with exertion and after discontinuing medications prescribed for post-concussion symptoms; (3) their balance error symptom scores were back to baseline, when available, and (4) their computerized neurocognitive test scores were at or above baseline values, when available.  When baseline neurocognitive scoresd were unavailable, scores with in the age-adjusted published norms and consistent with estimates of pre-injury levels of functioning obtained by eliciting history regarding previous neuropsychological testing, academic performance, patient subjective reporting, and parental observations, were used.

Because the balance error scores and computerized neurocognitive assessments are not routinely performed outside of the office and typically occur only at clinic visits, determining when actual recovery occurred was difficult, so that duration of post-concussion symptoms - defined at the time between the date of injury and the athlete's last date of symptoms, which was queried at each visit, was used as the primary outcome.

Only total score on the PCSS at the initial visit and cognitive-activity days were independently associated with duration of symptoms. Gender, age, loss of consciousness, amnesia, and number of previous concussions were not independently associated with time to symptom-resolution. 

1. 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.

2. McCrory P, Meeuwise W, Aubry 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.

3. Halstead, M, Walter, K. Clinical Report - Sport-Related Concussion in Children and Adolescents. Pediatrics. 2010;126(3):597-615.

4. 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.

5. 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.

6. 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.

7. 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. 

8. 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.

9. Halstead ME, et al. Clinical Report - Returning to Learning Following a Concussion. Pediatrics doi:10.1542/peds.2013-2867 (epub October 27, 2013).

10. McGrath N. Supporting the student-athlete's return to the classroom after a sport-related concussion.  J Athl Train. 2010;45(5):492-498.  

11. Deborah Kotz. "Children's Concussions and Brain Rest." Boston Globe. January 26, 2014,  http://www.bostonglobe.com/lifestyle/health-wellness/2014/01/06/brain-re..., accessed January 10, 2013.