Drowsiness, confusion, headaches, and sensitivity to light — it’s sometimes hard for doctors to spot the signs of a concussion based on the symptoms alone. Typically, CT or MRI head scans are ordered by physicians after a physical examination, but even these tests don’t always get it right. As a consequence, experts agree that concussion diagnoses are confusing for both neurologists and patients alike.
New research from the Penn State College of Medicine has revealed that molecules in saliva could help diagnose this traumatic brain injury in a non-invasive and non-biased way, cutting through this confusion.
Scientists obtained spit samples from a cohort of over 500 individuals and analyzed them, searching for microRNAs — tiny non-coding RNA molecules, each around 22 nucleotides in length. Cells use microRNAs to control the expression of genes, and these short fragments of genetic material are found in abundance inside cells, in the bloodstream, and, importantly, in the brain.
According to the scientists, microRNA levels present in the saliva could be altered after a concussion as there is a network of cranial nerves inside the oral cavity.
“Current methods rely on accurate symptom reporting and honest performance on neurocognitive testing,” said study lead Steve Hicks, associate professor of pediatrics. “Analyzing microRNA profiles in saliva following a head trauma is a non-invasive way to test for concussion that can’t be influenced by a patient’s feelings or motives.”
Around half of the study’s participants had reported a positive concussion diagnosis during the investigation, while the undiagnosed patients displayed symptoms such as fatigue and headaches, which could point towards the possibility of head trauma.
The scientists mapped the RNA profiles within saliva samples using sequencing technologies, creating a blueprint for what concussion-related microRNA changes look like. They then developed this into a diagnostic test, which successfully picked up concussions in 200 additional study participants.
“This method has lots of promising applications,” said Hicks. “A rapid, reliable diagnostic means that early, appropriate action can be taken to alleviate the symptoms of patients with concussions.”
A “spit test” diagnostic device for concussions would fast track clinical interventions for brain injuries, particularly for emergency first responders and for athletes.