Your child just took a hard hit on the playing field.

Maybe they’re lying on the ground, maybe they’re stumbling around, maybe they look just fine.

You need to know, as soon as possible – do they have a concussion?

There are indeed specific signs of concussion in children that can be used to quickly suss out who might be in danger, researchers reported in the Journal of the American Medical Association.

“This study provides strong evidence as to which signs and symptoms strongly indicate that a child has a concussion,” study co-author Haley Chizuk, a research assistant professor of orthopedics at the University at Buffalo, said in a news release.

An estimated 1.1 million to 1.9 million children and teenagers suffer a concussion each year, researchers said in background notes.

Most kids shake off a concussion within a month, but about 30% experience persistent symptoms, researchers said. Left untreated, concussions can have long-term effects on a child’s healthy development.

For the new paper, researchers pooled data from 23 prior studies on concussion, all of which involved children. The kids were 5 to 18 years old in 22 of the studies, and 2 to 12 in the other study.

Headache and dizziness are key signs that increase the likelihood a child is concussed, the study showed.

On the other hand, a lack of headache lowers the odds of concussion in kids, researchers found.

“The absence of headache was the most useful symptom for decreasing the likelihood of concussion,” researchers wrote in their paper.

Mental fog, nausea, sensitivity to light and noise, drowsiness, fatigue and memory problems also proved to be key clues that a child has a concussion, researchers found.

Eye movements are another way to test for concussion, researchers said.

People can slowly wave an object – a finger, a tongue depressor – in front of a child to see how their eyes track its movement. Abnormal or jerky eye tracking is a sign of concussion.

“Presence of any of these symptoms should prompt removal from play and evaluation by a trained medical professional,” researchers wrote.

Chizuk said these signs should be known by everyone attending a youth athletic event – parents, coaches, trainers, doctors and even bystanders.

“Accurate and timely recognition of pediatric concussion is undoubtedly critical for improving patient outcomes,” she said.