How is the sleep study of a person with fatal familial insomnia different from another person with insomnia?
The sleep studyEEG of a person who has insomnia but not fatal familial insomnia (FFI) shows mainly delta wave activity (high-amplitude slow waves of sleep stage 3 or deep sleep) and episodes of “micro-sleep”. There are also brief bursts of K-complexes (large waves in sleep stage 2 or light sleep) and sleep spindles (small bursts of activity in sleep stage 2). Insomnia with this pattern is associated with perceiving something that isn't there (disturbed perception), moments of not being aware of self or surroundings (lapses of consciousness), and quickly changing and often extreme behavior or emotions (erratic behavior).
In people with FFI, sleep study EEGs contain a mixture of rhythms that are neither typical of wake nor of light sleep, and may be called “subwakefulness.” There is a clear absence of sleep spindles and K-complexes. Total sleep time is shorter and the sleep study shows only slow activity or desynchronization without rapid eye movements (REM).
Last updated: 1/20/2017
How can I learn more about the normal stages of sleep?
You can lean more about sleep stages and the importance of sleep at the following resources: