Empirical Evidence Supports Cognitive Rest After Concussion

January 6, 2014

This morning, I sat down with the lead author of a new study that measures the effect of cognitive activity on the duration of post-concussion symptoms, published this week in the journal Pediatrics. The lead author, Naomi Brown, MD, recently joined the Sports Medicine practice at The Children’s Hospital of Philadelphia after completing her sports medicine fellowship at Children’s Hospital Boston, which is where the research took place. Beyond discussing the key methods and findings, I was most interested in hearing what she considers as important for future research on how cognitive activity (or cognitive rest) affects pediatric concussion recovery, as well as the utility of the scale Dr. Brown and her colleagues developed to measure self-reported cognitive activity.

Study Methods and Key Findings

Among the 335 participants ages 8-23 years that were included in the analyses, Dr. Brown and her team assessed self-reported concussion symptoms at each visit using an established instrument called the Post-Concussion Symptom Scale (PCSS). To assess cognitive activity, the research team developed a new scale with five levels of cognitive activity (0- complete cognitive rest, 1- minimal cognitive activity, 2- moderate cognitive activity, 3- significant cognitive activity, 4- full cognitive activity.) Each level had examples on what constituted that amount of activity. Participants used the scale to report their cognitive activity level at each follow-up visit. Cognitive activity-days were then calculated by multiplying the average cognitive activity level reported by the patient by the days between the visits. 

Cognitive activity-days were divided into quartiles and the relationship to time to symptom resolution was determined. Dr. Brown and her colleagues found that only the total score on the PCSS at the initial visit and the cognitive activity-days were independently associated with duration of symptoms. Specifically, patients in the highest quartile of activity (on the scale 4s and 3s) took statistically longer to recover than those on the 1st to 3rd quartiles (0-3s). It’s worth noting that the number of prior concussions was not a predictor in this analysis, perhaps because approximately 40% of the study population reported previous concussions. The analyses also controlled for all the usual predictor variables such as gender, age, amnesia and loss of consciousness at time of injury.

The study supports the recommended use of cognitive rest for treating concussion and the consensus opinion that limiting cognitive activity following a concussion injury reduces the duration of concussion symptoms.

What are the implications for future research that would be practical to clinicians?

Dr. Brown: From this analysis we learned that the highest levels of cognitive activity prolonged the timeline for recovery. We also learned that complete cognitive rest for the entire duration of recovery probably isn’t necessary. What we don’t know is the specific threshold of cognitive activity that is safe and doesn’t prolong recovery. It is likely that this answer varies by individual. It would be great to get to the point where we can predict who is most at-risk for prolonged recovery and who is less at-risk early in diagnosis. That way we could prescribe more rest for those more at-risk and allow others to return to normal levels of activity sooner. I think we’d all like to know when is the time to tell a patient to start using their brain to help with recovery- much like we do with ankle sprains. Research is needed.

Does the Cognitive Activity Scale add to our tools for data collection?

Dr. Brown: One of the biggest challenges in concussion research is the difficulty in collecting objective data about cognitive activity/rest. This is especially so among children who may not be able to understand what is “cognitive activity” as well as among adolescents who are not always forthcoming about symptoms. The Cognitive Activity Scale was developed by expert concussion clinician-researchers for the purposes of this study and it brings us closer to objectivity by its simple language, definitions and basic 5 levels. Today, it’s likely the best tool we have for assessing cognitive activity, but I need to stress that this scale is not validated.  More research using the tool is needed before we can call this instrument “validated.”

Dr. Brown completed her residency at CHOP in 2009 and we are so happy she has returned to CHOP to build her sports medicine practice (and life) here in the Philadelphia area. Welcome home, Naomi!