There’s strong evidence that children suffer from summer brain drain.

Come September, Jenny’s vocabulary and Johnny’s understanding of trapezoids will have atrophied a bit. Most students need weeks — if not months — to relearn some of what they knew in early June, studies show.

Turns out we adults suffer our own, more abbreviated version of brain drain. Call it cognition attrition or, for “Star Trek” fans, a mind melt.

Discombobulated by vacations, assailed by distractions, we forget when the kids are supposed to be at swimming lessons, we become less deft at finishing reports, we struggle to pay attention at meetings. It might be sunny outside, but our heads are in the clouds.

“If you’re lucky enough to have an office window,” said Diane Amundson, a Winona-based workplace productivity engineer, “you need to not look out it.”

Amundson cited three primary distractions: vacation, the kids being at home and — especially for those of us with prolonged winters — nice weather.

These factors wreak havoc on our work-life balance, said Naomi Pelley, regional director for the health management firm HealthFitness.

“It’s usually not brain drain, but schedule and distractions,” Pelley said. “We could say the same thing at Christmastime.”

Those distractions tend to take a higher toll on parents, Amundson said, especially with kids who are just old enough to be left at home.

“You get the phone call, ‘Mom, she looked at me,’ and you have that whole mental piece of kids being at home,” she said. “It has to have an effect.”

The uptick in vacations also creates a chain reaction.

“Often other people being on vacation works as a bottleneck to what you’re doing,” Amundson said. “You need a paper from Bob and you can’t get it, so you can’t finish this report for Cindy.”

Slide diminishes with age

A survey in 2011 found that just over a quarter of 2,600 hiring managers in the country think workers are less productive in the summer. But Pelley said there is little to no scientific research showing worker productivity dropping in the summer, just surveys.

The effects on our offspring, however, have been thoroughly recorded.

“Summer slide … is pretty well documented across the board” among elementary and high school students, said Scott McConnell, a University of Minnesota professor of educational psychology. He cited a knowledge baseline “that goes up from September to June and then dips and starts a little bit lower in September.”

That has spawned talk of all-year academic programs and “an ongoing discussion about summer,” McConnell said, especially around literacy. But he added that most research indicates that the issue diminishes as children age.

By the time we are adults, Amundson said, it’s more a matter of attention span than cognitive sliding. Sometimes in the workplace, it can even emanate from the top.

“If the boss is more laid-back in summer months, that lends itself to employees,” she said.

Some companies alter office hours in the summer, offering four-day workweeks or shorter hours on Fridays, ostensibly to boost flagging morale.

Productivity might still suffer, Pelley said. She cited a Captivate Network survey finding that 49 percent of employees working “summer schedules” report decreased productivity in the workplace, including 80 percent of those in offices that close early on Fridays.

Mind games people play

Actual time off can be a boost to our productivity — especially if we really get away from it all, Pelley said.

“We all know what happens the minute you turn on a device, or hear an e-mail ping, or start thinking, ‘I didn’t get that last document done before I left,’ ” Pelley said. And then we’re back at work.

Amundson, too, is a big believer in the rejuvenation potential of time away from work.

“Vacation is necessary and recharges us,” she said. “There are studies that say you need to get away. … But you should come back recharged and creative.”

It’s not just vacation that makes us feel better: Summer does that all by itself, but probably not as much as we think.

“Our perception is that we are more productive and more physically fit” in summer, she said. “We have longer days. We are outside more, more active. When it comes down to it, that’s just a perception, but probably not reality.”

That’s something to remember … if we can.