It is a disorder charactorised by excessive day time sleepiness, often disturbed night time sleep and disturbances in the REM sleep.
Decrease REM latency is the hallmark; REM sleep occures within 10 mins of onset of sleep.
Common age of onset is 15-25 yrs and continues thoughout the life.
Tetrad of symptoms:
1) sleep attacks:
– Person is unable to resist a sleep (nap)
– attack occures during nytime of the day
– gap of 2-35hrs betn two naps
– char’ by loss of muscle tone in various parts of body. e.g. Drop jaw
– may b precipited by sudden emotion
3) hypnagogic hallucinations:
– dreal like vivid perceptions which occures at the onset of sleep and associated with fearfullness
– these occuring at the time of awakening r called as hypnopompic hallucinations
4) sleep paralysis:
– this occures either at awakening or at sleep onset
– person is concius bt unable to move his body
– episode last for 30 sec to few mins
Other associated symptoms are:
Fugue states, blackouts, blurring of vision,
Diagnosis: confirmed by polysomnography which shows decreased REM latency
– forced naps at regular times in the day
– stimulant medicatin e.g. Amphetamine or modafinil