TOKYO - A new app that aims to improve both the quantity and quality of sleep uses brainwaves to track the amount of time spent in different stages of sleep.

Called Sleep Manager, the app synchronizes with a headset that measures brain activity, eye movement and other signals in light, deep and REM (rapid eye movement) sleep.

"The thing about sleep is that it's not just about how much you get - it's about the quality of your sleep," said Ben Rubin, co-founder of Zeo, which makes the app.

"In general, you want to optimize to get as much REM and deep sleep as possible."

A soft-sensor headband measures brainwave activity, muscle tone and eye movements, the same signals that would be taken by a professional sleep lab, but at a consumer level.

The signals are relayed through Bluetooth to the user's iPhone, iPad, or Android smartphone and uploaded to Zeo's website.

Rubin said that sleep tracking is only the beginning. After benchmarking sleep quality, Zeo uses this information to coach the user's sleep habits.

Studies have shown that when people wake up during the light sleep phase they are more refreshed, so the app has the ability to rouse users while in this state.

It also syncs with other apps such as RunKeeper, a running application, and DailyBurn, a nutrition planning app, to allow users to see how their sleep quality relates to their fitness and diets.

But not everyone is convinced that Zeo can provide accurate sleep data.

Rubin agrees there are limitations to the measurements that can be done but he said the app comes close to replicating a sleep lab.

"If you have two experts in a sleep lab scoring the same record, they agree with each other about 83 percent of the time," said Rubin. "Zeo agrees with those guys about 75 percent of the time. So we're about 7/8th as accurate as a full sleep lab," he added.

The company has an in-house sleep expert on their team, as well as an advisory board made up of sleep experts from Harvard University and the University of Colorado Bolder.