It's possible that not all screen time is equally bad for your child's performance at school. A new review of 58 studies from 23 countries found only the time spent watching television and playing video games negatively impacted a child's academics.

That's not really good news. On average, a typical child plays video games for 40 minutes a day and watches between 1.8 and 2.8 hours of TV each day. Almost a third of children and adolescents spend more than four hours a day on screens, with boys outpacing girls.

Impact of TV and video games

The study, published Monday in JAMA Pediatrics, compared the academic achievements of 106,000 children and adolescents, ages 4 to 18, to the amount of time spent on the internet, mobile phones, television, video games and overall screen media use.

Unlike previous research, this meta-analysis found overall screen time had no association with a child's performance at school. But when each type of screen time was broken down, the study found time spent on television viewing and video games was associated with poorer academic achievement.

Watching more TV impacted language and math abilities as well as an overall academic composite for teens; just language and math abilities were impacted in younger children. Teen scores appeared to be worse than those of younger children when the amount of time spent watching TV went up.

That makes sense, as studies have shown television viewing replaces time kids might spend studying, sleeping, talking and getting some exercise. Prior studies show excessive TV viewing reduces the ability of children to pay attention and think clearly, while increasing poor eating habits and behavioral problems.

In this study, playing video games seemed to only impact the academic composite score in teens. Video gaming has been linked to declines in verbal memory and restorative slow-wave sleep in school-aged children, but it has also been shown to improve motor performance and spatial abilities.

In prior studies, overall time spent on any screen has been linked to poor grades at school and various unhealthy behaviors. Based on this study, the authors feel that its time science examines the role of each type of screen, in the hopes that might help focus interventions by parents and educators.

More research is definitely needed, pediatrician Dr. Jenny Radesky, lead author on the American Academy of Pediatrics 2016 guidelines on screen use by children and adolescents, wrote in an email.

"The major limitation of this meta-analysis is that it examined studies from as far back as the early 1980s. Screens and digital media have changed so much since then," said Radesky, who was not involved in the study.

"Kids are immersed in digital media throughout the day now, and we need better measurement tools -- like apps that track what kids are doing on their device -- to truly measure children's interactions with, and reactions to, technology."

What's a parent to do?

The 2016 updates on the AAP's guidelines on screen time were in response to the growing prevalence of screens in our society. To help parents follow the guidance, the AAP has created an online family media planner, in which you can input your child's age and personalize a plan for his or her use.

Babies and toddlers

No baby under 18 months of age should be exposed to screen media, other than video-chatting with friends and family, the AAP says. Babies need to interact with caregivers and their environment, and not be placed in front of media as a babysitter.

In fact, a study found that even having the TV on in the same room with a baby or toddler negatively impacted their ability to play and interact.

By the time a baby turns 2 years old, they can learn words from a person on a live-video chat and some interactive touchscreens. The chief factor in facilitating a toddler's ability to learn from baby videos and interactives, studies show, is when parents watch with them and reteach the content.

Preschoolers

Children from ages 3 to 5 can benefit from quality TV shows, such as "Sesame Street," the AAP says. A well designed show can improve a child's cognitive abilities, help teach words, and impact their social development. But the AAP warns that many educational apps on the market aren't developed with input from developmental specialists and can do more harm than good when they take a child away from playtime with caregivers and other children.

"More than 80,000 apps are labeled as educational, but little research has demonstrated their actual quality," the academy says in its media planner. "Products pitched as "interactive" should require more than 'pushing & swiping.' Look to organizations like Common Sense Media for reviews about age-appropriate apps, games & programs to guide you in making the best choices for your children."

Just like toddlers, preschoolers learn much better from any educational materials when they are co-viewed, and the caregiver interacts with the child about the material.

"Feeling more socially connected and understood at home is positively associated with school success," Radesky wrote.

"Both TV and video games can have a social component -- when you play or watch with someone else -- and this can be a positive way that family members or peers engage with each other -- especially if it is intellectually stimulating content or has positive social messages."

Children 6 and older

Use the elementary years to set consistent limits on screen time as well as educating your child about the different types of content they can encounter on the internet. Starting now will make it much easier when they are heading into the teen years.

Radesky suggests not using the term "dangers" when teaching about the pitfalls of the web, but instead instilling a healthy skepticism through both teaching and role-modeling about disinformation and the persuasive power of the internet.

"This applies to advertisements, whatever is showing up in their video or social media feeds, or what other people are posting," Radesky suggests.

"It's still important to teach them about hacking, trolls, and people who are pretending to be someone they are not, but at the same time they should also be aware of when more minor design differences are trying to change their behavior -- persuasive design features that make them stay on devices longer, post one more thing, or feel compelled to check notifications."

Keep activity levels up

Make sure that screen time of any sort doesn't take the place of quality sleep, exercise and healthy eating habits. Eating in front of the TV has been linked to the growing obesity epidemic in America. A lack of sleep, which is also becoming an epidemic, can cause poor attention, bad grades, irritability and depression and increased risk-taking behaviors.

Continue co-viewing

Parents shouldn't stop co-viewing television or playing video games with their children just because they are growing up. If you stay connected to what your child is doing, there will be excellent teaching moments.

"As games have diversified in their content, they contain excellent opportunities to have conversations about everything from perseverance, to dating, and even grief," said Marientina Gotsis, who directs the Creative Media & Behavioral Health Center in Los Angeles, which produces games for health, sports and wellness.

Radesky points out that many children with ADHD or other learning disabilities who struggle in school will often seek out video games "as a way to 'zone out' after a hard day at school -- or as a way to feel more successful, since video games have carefully planned rewards and are inherently satisfying."

"So my first takeaway for parents is: if your child is struggling in school, expressing that they don't like school, and are avoiding schoolwork -- then try to avoid letting them spend their afternoons all in front of video games or streaming videos," she wrote.

"A little bit is fine, but it's important for children with learning challenges to develop other areas of confidence -- such as music or sports -- that help them feel effective.

Mobile devices

Radesky points out that watching TV or playing games on mobile devices is a solo experience, and too much of it can be isolating. (Parents, that applies to you too.)

"We all need a little alone time, but parents should try not to let kids only watch on their individual devices," Radesky said. "Kids learn a lot more from media when they can talk about what they're seeing -- the good and the bad -- with their parents or siblings."

Good quality sleep

Because kids wind up when they are sleep deprived, it can be tough for a parent to stay on top of their sleep deficit, according to the National Sleep Foundation. Kids ages 6 to 13 need 9 to 11 hours of sleep a night; while teenagers age 14 to 17 need between 8 and 10 hours of daily sleep.

Ban use of the devices one hour before bedtime, as everyone (parents too) need time away from the blue light and interactivity of screens to create a mindset for sleep. Blue light affects the release of melatonin, the sleep-hormone, so using an electronic device before bed means it will take your child longer to fall asleep, and disrupt it's quality.

Instead, read a book to your young child or and have older ones listen to soft music. Meditation is excellent -- it's a great skill to teach a teen.

Screen-free times and zones

Another tip from the AAP's family media plan is creating screen-free zones and times. Don't allow your child to recharge their cellphone or laptop in the bedroom, as the dings from incoming messages (and the blue light) can keep waking them up. Even slight awakenings can disrupt the quality of sleep.

Make the kitchen and dining room table screen-free zones. Studies show that children are healthier and do better at school when families eat together and talk. And don't eat in front of the TV.

In the end, screens are not a threat, it's the overuse of them that is. Use them appropriately, Gotsis explained, and your child will benefit.

"When technology facilitates social connectedness, pleasure, learning and leisure, it is positive for development," Gotsis said. "But technology is merely a magnifying lens for what exists. It is policy and human relationships that make all the difference."