T14 Sleep-Wake Disorders

• What is the main consequence of acute or chronic sleep reduction?

  Excessive sleepiness.
• What is sleep deprivation?

  When sleep loss is accompanied by impaired functioning.
• Neurocognitive symptoms of chronic sleep deprivation can mimic what?

  Psychiatric symptoms.
• What group is most vulnerable to negative effects of sleep deprivation?

  Children and adolescents.
• Sleep deprivation can cause psychomotor impairments similar to what BAC?

  0.05 - 0.1.
• What can irregular sleep cause?

  Lower HDL cholesterol, higher waist circumference, increased blood pressure, increased total triglycerides, increased fasting glucose.
• What is considered excessive sleep?

  More than 9 hours in adults.
• Sleeping more than 9 hours and napping more than 90 minutes has the highest likelihood of having what?

  Stroke.
• How is sleep measured?

  Electroencephalography
• What are the two states of sleep?

  NREM and REM.
• What are the stages of NREM sleep?

  N1, N2, N3.
• What is stage N1?

  Transition between awake and sleep.
• What happens during N1?

  Body temperature drops, muscles relax, slow rolling eye movements, loss of awareness to environment but can be easily aroused.
• What happens during N2?

  Heart rate and respirations drop and arousal needs more stimuli.
• What is N3?

  Slow wave sleep or delta sleep.
• What happens in N3?

  Heart rate, respirations, blood pressure and response to external stimuli are further reduced.
• What stage of sleep is considered restorative sleep?

  N3.
• Which NREM stage takes up the most sleep time?

  NREM Stage 2 with 45 - 55%.
• How much sleep time does NREM sleep take?

  75 - 80%.
• What is sleep latency?

  Time taken to fall asleep.
• What tests are used to diagnose narcolepsy?

  Polysomnography (PSG), Multiple Sleep Latency Test (MSLT).
• What is cataplexy?

  Sudden loss of muscle tone.
• What is cataplexy triggered by?

  Strong emotions and can last for up to several minutes with immediate and complete recovery.
• What are two classic symptoms of narcolepsy?

  Hypnagogic hallucinations (false hallucinations), sleep paralysis.
• What are treatments for narcolepsy that are not drugs?

  Scheduled naps, exercise, and a balanced diet.
• What is the most common sleep test?

  Polysomnography.
• Which neuropeptide is affected by patients with narcolepsy?

  Orexin.
• How does polysomnography test sleep?

  Involves one or two nights of sleep in a lab with electrodes and monitors on the head, chest, and legs.
• What does polysomnography test for?

  Sleep related breathing disorders and nocturnal seizure disorders.
• What two tests are done to determine if someone has narcolepsy?

  Polysomnography and Multiple Sleep Latency Test.
• How much sleep time does REM sleep make up?

  20 - 25%
• What is REM sleep characterized by?

  Reduction and absence of skeletal muscle tone (muscle atonia), bursts of REM, myoclonic twitches of face and limb muscles, dreaming, and autonomic nervous system variability.
• Sleep normally begins where in an adult?

  NREM.
• How many NREM and REM cycles occur over 90 - 120 minute intervals across a sleep period?


  4 - 6.
• What half of sleep is NREM?

  First half.
• The shortest REM period happens when and how long does it last?

  60 - 90 minutes after sleep onset and lasts for several minutes.
• When is the longest REM period and how long does it last?

  End of sleep period and can last up to an hour.
• What is the structural organization of NREM and REM sleep called?

  Sleep architecture.
• What is a hypnogram?

  A hypnogram is a graphical representation of the stages of sleep over a period of time.
• What is sleep continuity?

  Distribution of sleep and wakefulness across the sleep period.