Sleep Disorders  Hypersomnias    Disorders of Excessive Sleepiness •     Recall that Dyssomnias include disorders of     excessive sleepiness – also known as Hypersomnias:     • Narcolepsy - characterized by extreme          sleepiness Sleep attacks - sleep at inappropriate     times  (such as during a conversation, while     driving)  Cataplexy - loss of muscle tone during      the day (often occurs during experiencing of     strong emotions, causes collapse)         Hypnagogic hallucinations - seeing or     hearing things while falling asleep         Sleep paralysis - when waking from sleep,     having sensation of paralysis (usually a     frightening experience)     •     There are different forms of Narcolepsy of         lesser severity, such as Idiopathic         Hypersomnia      •        Must first tease out medical problems (e.g.,         hypothyroidism), psychological problems         (e.g., depression) and potential medication         issues      Hypersomnias - Diagnosis &   Treatment           To diagnose a hypersomnia, one must have      a normal overnight PSG, followed by a      Multiple Sleep Latency Test (MSLT) the      following day.  A MSLT involves a series of      nap trials throughout day (~ 20 minutes,      every two hours). A diagnosis of Narcolepsy      requires that one fall asleep on average      within five minutes during the nap trials, and      that REM sleep is observed on at least two      of the nap trials. Other hypersomnias are      diagnosed similarly, with different criteria.      One in two thousand Americans have      Narcolepsy. The onset of Narcolepsy      usually occurs by adolescence and often      takes years to diagnose. This disorder is      likely under-diagnosed. Narcolepsy and      other hypersomnias are treated most often      with stimulant medication. Behavioral      treatments are also utilized, such as      scheduling naps.