Severe injuries can also cause lasting effects that vary — including memory loss, paralysis, seizures, and lasting behavioral or cognitive changes — depending on the areas of the brain affected. But in those cases, unconsciousness is a symptom of the injury, not a cause of long term deficits.

Can getting knocked out cause brain damage?

CHICAGO (Reuters) - A blow to the head that knocks a person unconscious can result in widespread loss of brain tissue, Canadian researchers said on Monday, explaining why some people who suffer head injuries are never quite the same. The more severe the injury, the more brain tissue is lost, they said.

How long can you be knocked out before brain damage?

A moderate brain injury is defined as loss of consciousness for between 15 minutes and 6 hours, or a period of post-traumatic amnesia of up to 24 hours.