From blows to the head on the sports field, to car crashes and playground falls, concussion is a common brain injury notoriously difficult to diagnose -- until now, researchers said Thursday.
A US-based team unveiled a fast, portable and reliable test measuring differences in brain activity in response to sound.
"Our measure... can take the guesswork out of concussion diagnosis," study co-author Nina Kraus of Northwestern University in the United States, told AFP.
"We have found that concussions disrupt how the brain processes sound and this disruption, which can be non-invasively measured, can potentially diagnose and manage concussions."
Concussion occurs when a hard blow causes the brain -- a soft organ cushioned by a layer of fluid inside our protective skull -- to jolt violently.
In severe cases it can lead to bruising, as well as injury to the nerves and blood vessels.
A concussion can be mild to severe, with symptoms ranging from loss of consciousness or amnesia to headache and confusion.
Severe cases may require surgery to relieve brain swelling or a buildup of blood in the skull.
For diagnosis, doctors need to know what happened to the patient, and consider a vast basket of symptoms -- some of them obvious, others not.
X-rays and other scans often fail to pinpoint the damage, and telltale signs such as disorientation, slurred speech or memory loss may be absent or hard to spot.
- Same sound, different waves -
Diagnosis "requires judgment and balancing many potential factors," said Kraus. "Our discovery makes it more like a thermometer -- yes or no, is there a concussion here."
The new test involves placing three small sensors on the skull, having a person listen to a sound, then measuring brain activity.
For this study, two groups of children -- some diagnosed with concussion and the rest healthy -- were exposed to the same sound.
"What differed is the amount of brain activity that their brains generated in response to that sound," Krause explained.
The concussed children -- previously diagnosed by a different physician -- showed less brain activity, the researchers found.
The team was confident the technique would work in adults too.
The new tool represents "a single, fast test that does not require advanced training to administer," said Kraus.
It can also be used to track recovery in a patient, allowing doctors to better determine when the patient can resume normal activities after a period of rest and recovery -- the main course of treatment.
Previous research had shown that the risk of suicide among adults who suffer a concussion triples, while survivors of traumatic brain injury are three times as likely to die younger.
The study was published in the Nature journal Scientific Reports.
A video explaining the method can be watched here: http://brainvolts.northwestern.edu/demonstration.php