NEW YORK - Researchers are reporting the first treatment to speed recovery from severe brain injuries caused by falls and car crashes: a cheap flu medicine whose side benefits were discovered by accident decades ago.

Severely injured patients in the United States, Denmark and Germany who were given amantadine got better faster than those who received a dummy medicine. After four weeks, more people in the flu drug group could give reliable yes-and-no answers, follow commands or use a spoon or hairbrush - things that few of them could do at the start. Far fewer patients who got amantadine remained in a vegetative state, 17 percent versus 32 percent.

"This drug moved the needle in terms of speeding patient recovery, and that's not been shown before," said neuropsychologist Joseph Giacino of Boston's Spaulding Rehabilitation Hospital, co-leader of the study. He added: "It really does provide hope for a population that is viewed in many places as hopeless."

Many doctors began using amantadine for brain injuries years ago, but until now there's never been a big study to show that it works. The results of the federally funded study appear in Thursday's New England Journal of Medicine.

A neurologist who wasn't involved in the research called it an important step. But many questions remain, including whether people less severely injured would benefit, and whether amantadine actually improves patients' long-term outcome or just speeds up their recovery.

Each year, an estimated 1.7 million Americans suffer a traumatic brain injury. Falls, car crashes, colliding with or getting hit by an object, and assaults are the leading causes. About three-quarters are concussions or other mild forms that heal over time. But about 52,000 people with brain injuries die each year and 275,000 are hospitalized, many with persistent, debilitating injuries, according to government figures.

With no proven remedies to rely on, doctors have used a variety of medicines approved for other ailments in the hopes that they would help brain injury patients. Those decisions are based on "hunches and logic rather than data", said Dr. John Whyte, of the Moss Rehabilitation Research Institute in suburban Philadelphia. He led the study along with Giacino.

Amantadine, an inexpensive generic, was approved for the flu in the mid-1960s. The first hint that it might have other uses came a few years later when it appeared to improve Parkinson's symptoms in nursing home patients. It was found to have an effect on the brain's dopamine system, whose many functions include movement and alertness, and it was later approved for Parkinson's.

It's now commonly used for brain injuries, and the researchers felt it was important to find out "whether we're treating patients with a useful drug, a harmful drug or a useless drug," Whyte said.

The study involved 184 severely disabled patients, about 36 years old on average. About a third were in a vegetative state, meaning unconscious but with periods of wakefulness. The rest were minimally conscious, showing some signs of awareness. They were treated one to four months after getting injured, a period when a lot of patients get better on their own, Giacino noted.

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