Association of salivary microRNA changes with prolonged concussion symptoms

Johnson JJ, Loeffert AC, Stokes J, Olympia RP, Bramley H, Hicks SD. 2017. Am J JAMA Pediatr: ahead of print.

Take Home Message: Measuring levels of microRNAs in saliva may help predict who will have prolonged concussion symptoms.

Clinical tests that enable medical professionals to predict the length of concussion recovery would be helpful to curate rehabilitation programs and to decrease the athlete’s anxiety of when they can return to daily activities. Currently, no such tool exists. Epigenetic molecules known as microRNAs change after a traumatic brain injury; however, no one has examined the predictive ability for microRNA to detect prolonged concussion recovery. Therefore, the authors evaluated 52 people between ages of 7 and 21 years to determine the efficacy of salivary microRNAs to identify people with a concussion who are at risk for prolonged symptoms. The authors collected demographic and concussion history information and used the SCAT3. The participants then provided a saliva sample for microRNA analysis. They repeated the SCAT3 at 4 and 8 weeks post injury. Thirty participants had a SCAT3 score of 5 or more on self report and/or parent report at 4 weeks and were classified as having prolonged concussion symptoms. Twenty-one participants scored less than 5 on the SCAT3 at 4 weeks post injury or reported an absence of symptoms at a follow-up clinical encounter and were classified as having acute concussion symptoms. Fifteen microRNAs were analyzed and 5 microRNAs had a sensitivity of 80% and specificity of 75% for prolonged concussion symptoms. These microRNA were associated with genes related to synaptic development, neuronal migration and repair, and nervous system development. Levels of 3 miRNAs were associated with specific symptoms 4 weeks after injury (memory difficulty, headaches, fatigue).

The authors found that levels of specific microRNA may help clinicians predict who will have a prolonged recovery and what type of symptoms the athlete may suffer. An objective post-concussion tool could also inform clinical recommendations about return-to-play and school-based accommodations. Additionally, knowledge about what specific long-term signs and symptoms the athletes may suffer may help clinicians develop an individualized rehabilitation program. However, further investigation with a larger cohort is necessary. It would also be interesting to see if these microRNAs are associated with positive scores from the other assessments included in the concussion evaluation protocol (balance, vestibular ocular). At this time, medical professionals will need to continue to rely and proper education, performing a full concussion evaluation, and allowing an open line of communication to discuss recovery goals and rehabilitation plans following a concussion.

Questions for Discussion
: Would measuring microRNA levels at the time of injury to predict recovery be helpful to you in your clinical practice? What barriers do you see for measuring microRNAs from saliva?

Written by: Jane McDevitt, PhD
Reviewed by: Jeff Driban

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