According to new research published in JAMA Pediatrics, molecules in saliva might be able to diagnose, predict the length of concussions in children. Researchers measured the levels of microRNAs in the saliva of concussion patients. The team found that the presence of certain microRNAs in saliva was able to better identify concussions and more accurately predict the length of concussion symptoms than relying solely on patient surveys.

Previous research has focused on proteins, but this approach is limited because proteins have a hard time crossing the blood-brain barrier. The current study looked at microRNAs instead of proteins and looked in saliva rather than blood.

Concussions usually occur after a blow to the head that could cause a headache, nausea, confusion, amnesia or lack of consciousness. While most concussions clear up within two weeks, about one-third of patients will experience symptoms longer.

Patients are usually advised to rest and stay away from such physical activity as sports or gym class until their symptoms subside. Hicks said that while it is important to give the brain enough time to heal, it is difficult to accurately predict how long patients should rest.

The tools that used to diagnose and manage concussions are subjective. Researchers do a physical exam and then have them answer a survey about their symptoms. Then, make an educated guess about how long that child might continue to have a headache or feel nauseous. However, the guesses are not evidence-based and are not always accurate.

MicroRNAs are found throughout the body and affect how genes are expressed depending on different conditions (disease or injury). The researchers suspected these biomarkers might be able to predict the presence and length of concussions.

The researchers recruited concussion patients (n=52, age=7-21). Each participant was evaluated using the Sports Concussion Assessment Tool (SCAT-3, a common tool that doctors use to inventory concussion symptoms and severity) within two weeks of their injury.

In the study, the researchers also collected saliva from each participant and analyzed for levels of different microRNAs and compared the microRNA profiles to the patient's symptoms at both the initial and follow-up assessments.

The researchers isolated five microRNAs that could accurately identify the participants who would experience prolonged symptoms. The microRNAs could correctly identify if a participant would have prolonged symptoms or not for 42 of 50 participants.

The microRNAs were able to predict whether symptoms would last beyond four weeks with about 85% accuracy. In comparison, using the SCAT-3 report of symptoms alone is about 64% accurate.

Predicting the length of concussions as early as possible would help ensure patients get the right care, and advise patients and parents on how long to expect symptoms to continue. While further studies are required to determine that measurement of microRNAs in saliva could be an accurate, quick way to diagnose and manage concussions.

The final goal is to identify that a concussion has happened and then predict how long the symptoms will go on for. Then the knowledge could be used to improve the care that provides for children who have concussions, either by starting medicine earlier or holding them out of activities for longer.