For humans this happens chiefly during deep sleep, stages 3 and 4, which differ in the percentage of brain activity that’s composed of big, rolling delta waves, as measured on an EEG.

If I were looking at you in a sleep lab, I could actually look at your EEG recordings and I could look at how much stage three, four and REM sleep you get because that really is the determinant of ...

InteraXon, the makers of the Muse wearable EEG, believe it’s made a big leap ... Naturally, when worn to bed, you’ll get a record of your sleep stages, including how deep your sleep is.

InteraXon, the makers of the Muse wearable EEG, believe it’s made a big leap in scanning your brain’s health. It is launching ...

"The new, FDA-approved treatments for Alzheimer's disease are effective at the earlier stages of dementia ... stimulation can alter EEG patterns in sleep and thereby slow down cognitive decline.