The technology does exist. Not quite like the device they've got, but they're really just creating a gadget or toy, maybe. Good for gaming, basic phone functions, maybe. The tech that exists comes at a much higher price point and is developed by supremely skilled teams...not quite the storage closet in an insurance office, by 2 dudes checking out their tan lines in the mirror...http://www.extremetech.com/extreme/184159-mind-controlled-exoskeleton-prepares-to-kick-off-the-world-cup
Eeg waves have been recorded since the 50s. A wave has a peak and valley. That makes it binary. A Binary signal can be recorded and mapped. Given time why coukd it not be?
Light waves were tecorded and mspped in just such a manner when it was discovered that colored light on solar cellls gave slightly different wave lengths which evolved into digital colored pixels which became a picture on a computer or phone.