Pablo Cano-Lopez told detectives he was at "the breaking point" when he lifted his crying stepson, 4-month-old Elijah Llanos, and shook him four or five times. The baby stopped crying and whimpered before falling asleep.

Six hours later, Elijah's lips had turned blue. He was rushed to a hospital, but by the next day, Feb. 19, 2006, he was pronounced dead.

"He just kept on crying again, and that's when I … I just got irritated, man," Cano-Lopez told police, according to transcripts. "That's when I shook him."

Lopez, 23, of Lake Worth, Fla., confessed and was convicted in May of manslaughter and aggravated child abuse. He was sentenced July 11 to 20 years in prison.

"It's hard to understand," says Robert Gershman, Cano-Lopez's defense attorney. "He loved his children and, in a moment, shook the child out of not only frustration but irrational thinking. Not until it's over does he realize it's wrong, and he should have walked away."

HEALTH BLOG: News and research on caring for kids

Armed with data linking shaken baby incidents to periods of increases in infant crying, researchers in North Carolina and Pennsylvania are teaching parents how to cope with crying babies instead of simply saying, "Don't shake your baby."

"We don't think that shaken baby is the same kind of child abuse as battered-child abuse," says Desmond Runyan, a pediatrician at the University of North Carolina-Chapel Hill who is leading the state's prevention efforts. "It's somebody who lost it for 30 seconds and changed their life and life of the child.

"We're trying to prevent that unfortunate event."

Horrific damage

When a child is shaken, the head whips back and forth and the brain crashes against the skull. Typically, there are no outward signs of abuse, but the child may have bleeding in the brain or eyes.

Shaken-baby syndrome kills 15% to 35% of all victims. Half the survivors often suffer severe brain damage, such as the 10-year-old girl named Winter who was shaken by her father when she was 9 weeks old.

The father told investigators Winter had stopped breathing and he shook her to revive her, says Chris DeMartino, the district attorney in San Antonio who prosecuted the case. The father was convicted in 2000 of felony child neglect, fined $10,000 and sentenced to five years' probation.

Winter cannot speak, eat solid food and is blind because of damage to her optic nerve. She needs oxygen to breathe at night and medication to sleep.

"He made a horrible, tragic mistake, and in the five seconds it took to shake Winter, he ruined her life," says Care Burpee, Winter's mother.

Official numbers are hard to come by, but since the National Center for Shaken Baby Syndrome launched a victim database in 1998 by cobbling together information from news reports, 3,286 victims have been identified in the USA.

'The right time' for action

"Parents already knew that violent shaking was a bad thing," says Mark Dias, a neurosurgeon who developed prevention programs in New York and Pennsylvania. The program has parents review information about the syndrome, and they have one-on-one counseling with a nurse after the baby's birth. "They needed to be reminded in the right time and in the right setting."

Researchers are hoping to replicate results of a pilot program created by Dias in upstate New York that reduced such cases by 47% from 1998 to 2003.

In North Carolina, every family with a new baby now receives a DVD and a booklet describing the "period of PURPLE crying," an acronym that helps parents understand all children increasingly will cry uncontrollably from about 2 weeks old until about 5 or 6 months. P stands for peak of crying; U for unexpected; R for resists soothing; P for pain-like face; L for long-lasting; E for evening.

The message is repeated by a nurse after the birth and again by a pediatrician at the child's checkups at 2 months and 4 months.

Message received

"We're trying to get people — the whole society, not just mothers and fathers … to understand early infant crying is not because the baby is bad or because the parents are bad," says Ron Barr, who created the PURPLE program and studied the link between shaken babies and crying.

The programs encourage parents to put a crying child in a safe place and walk away before they get too frustrated.

"What I see here is the relief when a parent hears (uncontrollable crying) is normal," says Cindy Brown, a pediatrician at Mission Hospital in Asheville, N.C., one of the first medical centers in the state to distribute the prevention materials.

Both programs, which are financed for five years in part by the Centers for Disease Control and Prevention, will track infant head traumas until 2012.

Says Runyan, "It's our view that the majority of shaken babies are not premeditated but a desperate parent who has run out of gas who needs the kid to be quiet."