Definition

A short period of time (seconds) when the brain disengages from the environment (it stops processing visual information and sounds) and slips uncontrollably into light non-REM sleep. Micro-sleeps are a sign of extreme physiological sleepiness.

Source: ICAO Doc 9966: Manual for the Oversight of Fatigue Management Approaches

Description

Micro-sleep is normally defined as a sleep episode lasting 15 seconds or less. The person may or may not close their eyes during that time but in any case the processing of external information is interrupted. Also, the person is normally not aware of what they have just experienced and has no memory of their actions (or lack thereof) during the episode. They often assume that they stopped paying attention to their environment rather than recognizing that they have fallen asleep for a short time.

Common symptoms of micro-sleep include: