Just in time for the summer doldrums: Fresh evidence from a prominent Minnesota researcher that kids who spend too many hours with TV and video games can be at risk for attention problems.

Children whose total screen time exceeds two hours a day are almost twice as likely as other kids to develop attention problems, according to a study co-authored by Twin Cities psychologist David Walsh and published in the August issue of Pediatrics.

The study found equal risks whether children exceed the daily time limit with television, video games or both -- making it one of the first to substantiate gaming as a risk factor in attention problems.

Midsummer is the ideal time to call attention to the link, Walsh said.

"For some kids, this becomes a time when their media diet gets even more out of balance," he said. "It's such a temptation for kids to while away the hours just playing a video game or watching TV."

Not everyone buys the link between gaming and attention problems. Some studies have pointed out benefits from certain types of gaming, including improved problem-solving skills and hand-eye coordination.

The American Academy of Pediatrics, however, already recommends that parents limit children to fewer than two hours of non-educational screen time each day.

Walsh said his study advances the science in several ways, including its unique look at gaming. "Video games are for this generation of kids what television was for previous generations," he said. He said even this study is behind the times because it doesn't account for texting and social media.

The study is also one of the largest and longest to examine the issue. It monitored 1,300 elementary school-age children over 13 months. The researchers surveyed teachers at four points on whether students were developing attention problems. They also asked 200 young adults to self-report their levels of screen time and attention problems for comparison.

Twin Cities parents didn't need a new study to fret about screen time.

Walt Madden, a former special education teacher from Bloomington, sets a timer to 25 minutes when his two kids watch TV at night -- giving them a five-minute warning before it goes off. (Sometimes they earn extra viewing time if they exercise or play nice.) He also has his 12-year-old son and 8-year-old daughter turn in their portable games and phones at night.

Summer is trickier, he said, because both he and his wife work and the kids are home, watched some days by their grandmother. Madden's wife sets the TV to turn off after a certain amount of time during the day, but that isn't surefire.

"The TV turns off," Madden said. "It doesn't mean the DS [a hand-held game] turns off."

Trish Doede of Stillwater worries more about school performance than video games for her boys, now that they're 17 and 15. "During the school year, it's easy to manage," she said. "We watch the grades every day and if the grades slip, it's bye-bye to the games for a little while."

The summer presents a bigger challenge, she said. While the boys have weight training for school sports and yard work at their grandmother's house, they have "ample" free time, she said. Still, Doede said she'll "pull the plug" if the boys aren't getting chores done.

Some days her sons invite friends over for marathon Xbox parties. Each friend brings his own TV and game system so they can play "Call of Duty" online together. Often a break from gaming means watching a movie. The bright side?

"They're at my house," Doede said, "and I know what they're doing."

Walsh's study, released last week in advance of publication, was criticized on the Pediatrics website by a Harvard psychiatrist and a psychologist from Texas A&M. They argued the study, at best, found a weak correlation between gaming and attention problems and used an unproven method for surveying teachers about attention problems in kids.

Walsh wasn't aware of the specific criticisms but acknowledged limitations of the study, which was co-written by researchers at Iowa State University. The researchers couldn't prove cause-and-effect; it's possible, for example, that kids with attention problems are more predisposed to like video games or TV. Also, the study assesses only perceived attention problems in kids, not whether screen time leads to disorders such as attention deficit-hyperactivity disorder.

Walsh stressed, however, that the findings are consistent with other studies about TV time for children.

Doede, the Stillwater mom, also wonders sometimes if gaming has benefits.

"They're memorizing, like, all of these 300 Pokemon [characters] and this one has this power and that one has that power," she said. "Maybe they'd be better off memorizing presidents, but they're still using their heads."

Walsh said the study isn't an indictment of screen time, just a call for moderation. "We're not talking about the smoking gun," he said. "The common sense reaction to a study like this is that balance is important."

Jeremy Olson • 612-673-7744