More commonly refered to as the
MSLT, this tool in the diagnosis of
narcolepsy measures time to
sleep onset after the patient is instructed to fall asleep while lying down in a dark, quiet room.
In practice, unfortunately, there exist some problems with this test. While in my own room, falling asleep is as easy as, well, falling asleep, falling asleep in a sleep clinic with infrared cameras pointed at me, electrodes glued all over my scalp and body, a pulse sensor on my finger, and an CO2 sensor looped under my nose is not. I've done my own version of the MSLT at home, using a video camera and the "sleep latency drop test", where my average sleep latency was about six minutes; my "official" time, as recorded by the Princeton Hospital Sleep Clinic, was nearly twenty.