May 16, 2014
Effect of Cognitive Activity Level on Duration of Post-concussion Symptoms
Brown NJ, Mannix RC, O'Brien MJ, et al
Current guidelines, agreed upon by international professional organizations, recommend cognitive rest after concussion. Randomized data to answer the question of whether cognitive rest will speed concussion recovery are not available, so current recommendations are based primarily on observational studies. This study by Brown and colleagues is also observational, but it was conducted in a prospective manner, enrolling children at a single sports concussion clinic from 2009 to 2011. Participants were enrolled early, within 3 weeks of a sport-related concussion. Children with concussions from motor vehicle accidents or significant falls were excluded. Recovery was defined as:
- being symptom-free at rest;
- being symptom-free with exertion after being off all medications prescribed for concussion symptoms; and
- balance scores and computerized neurocognitive test scores, when available, were back to baseline values.
The primary outcome was the duration of postconcussion symptoms, which were evaluated at each follow-up clinic visit. The primary outcome assessment was the child or adolescent's score on a standardized instrument that collected information on 22 postconcussion symptoms. To be considered symptom-free, the patient was required to report a zero for each of the 22 symptoms. The children self-reported their cognitive activities for the previous interval at each of the follow-up visits, using a cognitive activity scale that ranged from "complete cognitive rest" to "full cognitive activity." Descriptive anchors were provided for each of the 5 levels of cognitive activity. From this, the investigators calculated cognitive activity quartiles and grouped the children accordingly for analyses.
This report includes the analysis of data on 335 children (mean age, 15 years; 62% boys) who met the enrollment criteria, 39% of whom had experienced a previous concussion. A loss of consciousness at the time of concussion occurred in 19%, and 37% reported amnesia for the event. The mean duration of the children's symptoms was 43 days. The Kaplan-Meier curves for duration of symptoms among the cognitive activity quartiles are striking. Children in the lowest 3 quartiles of cognitive activity had almost overlapping curves, with the large majority experiencing recovery by approximately 100 days, and 50% by 50-60 days. However, looking at the children in the highest quartile of cognitive function, 50% experienced resolution by 100 days, and in 75%, recovery took at least 300 days, suggesting a much longer duration of symptoms in the group with the highest cognitive activity levels during the recovery period. Brown and colleagues concluded that this study supports the recommendation for cognitive rest as a treatment for postconcussion symptoms.
Research on postconcussion cognitive impairment is picking up steam, and it is very helpful to pediatric practitioners to have such data available. I would like to have seen a greater dose-response relationship among the quartiles of cognitive activity to feel reassured that, even though these are observational data, randomized trial findings might be similar. However, the data are very clear that the group with the highest cognitive activity levels had different recovery profiles, perhaps putting themselves at greater risk for harm.
Another factor that I want to emphasize, which was not covered well in this article but has been emphasized very well by the American Academy of Pediatrics, is the importance of relying on neurocognitive testing to clear athletes after concussion.
Brown and colleagues relied on self-reported symptom scores, which are validated and important to collect, I suspect because neurocognitive data were not available for every subject. The neurocognitive testing may have provided more definitive data for symptom resolution. However, data increasingly show that cognitive impairment detected on computerized neurocognitive testing can be very subtle and more difficult to detect using symptom checklists. I wonder whether a greater dose–response effect would have been found if the outcome in this study had been computerized neurocognitive testing for all children.ABSTRACT: http://www.ncbi.nlm.nih.gov/pubmed/24394679
Halstead ME, Walter KD; The Council on Sports Medicine and Fitness.
Sport-Related Concussion in Children and Adolescents. Pediatrics. 2010;126:597-615.
Medscape Pediatrics © 2014 WebMD, LLC
Cite this article: William T. Basco. Cognitive Rest, Activity, and Recovery After Concussion. Medscape. May 16, 2014.