Children and young adults take longer to recover from a concussion if they've suffered a previous hit to the head within a year or repeated blows at any time, according to a new study.

Doctors had assumed it was bad for kids to get multiple knocks on the head, but the new study, from Boston Children's Hospital, is the first to confirm the connection and put a time frame on recovery.

The study found that kids and young adults, ages 11-22, who came to the emergency room with a repeat concussion — either within a year, or multiple times over a lifetime — took longer to recover than those with a first concussion. A single previous concussion more than a year earlier did not increase the risk for a longer recovery.

The new study, published in the journal Pediatrics, suggests that the effects may last longer than previously thought — something coaches and parents should consider in deciding when kids should return to the athletic field, says Matthew Eisenberg, a study author and physician at Boston Children's. "This just adds another little weight to the risk side," when weighing benefits and risks, he says.

Patients without a prior concussion took 12 days on average to recover, while those with several previous concussions took 28 days. Recovery from a second concussion within a year took 35 days, the study found. About 60% had been injured playing sports.

Source: USA Today
http://www.usatoday.com/story/news/nation/2013/06/10/pediatrics-concussions-recovery/2398307/