The test, unveiled at the American Academy of Neurology annual meeting in San Diego this week, involves autonomic reflex testing, which measures involuntary changes in heart rate and blood pressure typically seen in those with severe concussions.
 

Currently, doctors rely primarily on self-reporting of symptoms to make a diagnosis of concussion and there is no reliable test to determine when an athlete's brain has fully recovered from concussion. But research has shown there is a lag between when a patient reports that his or her symptoms have resolved and the time when the brain has actually healed.
 

As a result, the rapid, reliable, cost-effective tool developed by Mayo Clinic researchers could provide a more accurate assessment in such cases and help identify when a patient has fully recovered from concussion.
 

"This has the potential to change the way we approach concussion patients," said David Dodick, M.D., a neurologist and director of the Mayo Clinic Concussion Program. "One of the challenges of treating someone with a concussion is to reliably make a diagnosis: to know when the brain is injured and to know when the brain is actually recovered."
 

For the study, Mayo Clinic doctors monitored 21 patients after concussion, and all experienced significant abnormalities in heart rate and blood pressure during autonomic testing. The physicians concluded that these abnormalities are tied to the concussion.
 

"Contrary to popular belief, the symptoms of 'dizziness' that patients feel just after a concussion may, in some cases, be symptoms of autonomic system impairment rather than a vestibular or inner ear disturbance," noted Bert Vargas, M.D., a Mayo neurologist.
 

More research is needed, but the Mayo Clinic’s research is promising, Dr. Dodick said.
 

"This study shows a possible electrophysiological biomarker that indicates that a concussion has occurred — we are hopeful that with more research this will be confirmed and that this may also be a biomarker for recovery," he said.