A Japanese startup has invented a compact EEG called Sleep Scope that only uses two electrodes, TechinAsia reports.

“There’s no difference when monitoring for wake, REM, and the three sleep stages,” he says, claiming that the results have been consistent across more than 22,000 tests in Japan. PSG tests, known as polysomnograms, can detect sleep disorders like insomnia, narcolepsy, and sleep apnea.

Far from Japan, Sleep Scope is being utilized by Antarctic researchers to examine the difference in sleep patterns during months-long periods where there is continuous sun or continuous darkness. It’s even helping Japanese JAXA astronauts monitor their sleep patterns from inside the International Space Station.