Neurologists at Mayo Clinic in Arizona have developed a test that can help identify a concussion.

Doctors now rely primarily on self-reporting of symptoms to make a diagnosis of concussion. And there's no reliable way to test when a brain has fully recovered from concussion.

Mayo researchers found that autonomic reflex testing, which measures involuntary changes in heart rate and blood pressure, appears to demonstrate significant changes in those with concussion. The autonomic nervous system acts as an involuntary control system for heart rate, blood pressure, digestion, respiratory rate and perspiration.

In 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 conclude that these abnormalities are tied to the 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."

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