Heading off problems

Public middle schools and high schools in Massachusetts will take steps this fall aimed at keeping student-athletes in all sports off the dangerous path toward long-term damage.

Under a law passed by the Legislature last year, everyone involved with school teams - coaches, volunteers, players, parents, and other officials - must be trained annually in how to recognize concussions and get the appropriate care for students who suffer one.

Any student suspected of having a concussion now must be removed from play immediately and cleared by a doctor before returning. The law also calls for students diagnosed with a concussion to have a written plan for gradually returning to both athletics and academics.

The new rules are “a great step in the right direction,’’ said Dr. William Meehan, director of the sports concussion clinic at Children’s Hospital Boston, who sat on the state advisory panel that helped draft the rules.

While advocates agree that the changes are an important starting point, some argue that more needs to be done to keep children’s brains safe from a harm that is invisible but potentially lasting.

What exactly is a concussion? It is not a bruise on the brain. Nor does it involve swelling or bleeding. A concussion can occur when an athlete collides with another player, a goal post, or the ground, causing the brain to rattle or twist in the skull.

That prompts what is referred to as a “metabolic cascade,’’ a series of changes in which the brain’s nerve cells stop functioning as they should and blood flow is slowed. The process is not fully understood, in large part because researchers aren’t able to probe the brains of people who have suffered a concussion. And the effects are not visible on imaging tools, such as CT scans or MRIs.

If a person rests properly - meaning no physical activity beyond walking, and little cognitive activity - the brain can recover in almost all instances, said Dr. Robert Cantu, a Boston University professor of neurosurgery who has been studying concussions and advocating for better prevention among athletes for decades.