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Sleep and Sleep Disorders.ppt

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					 The Science of Sleep

     Robert Averbuch, MD
Assistant Professor of Psychiatry
          Lecture Outline
• Physiology of Normal Sleep
  – Non-REM
  – REM
  – Normal patterns of sleep
• Sleep Disorders
  – Dyssomnias
  – Parasomnias
Physiology of Normal
       Sleep
 2 Phases: REM and Non-REM
            Sleep
          Non-REM Sleep
• 4 stages of progressively deeper sleep
• Normal muscle tone
• Associated with increased 5HT
  (serotonin)
• Decreased autonomic activity:
  – Lower BP, Pulse, respirations slow
             Stage One
• Brief transition between wakefulness
  and sleep (accounts for only 5% of
  sleep time)
             Stage Two
• Light sleep
• Accounts for 50% of total sleep time
• ElectroEncephaloGram (EEG) shows
  some characteristic findings…
EEG in Stage 2
              Stages 3,4
• Most restful, restorative stages of sleep
• Aka: Delta wave sleep/ slow wave sleep
• Greatest proportion is in the first 1/3 to
  1/2 of night
 NREM Sleep: Theories of its
        purpose…
• The decrease in metabolic demand on
  the brain during NREM allows glycogen
  stores to replenish
• Allows for consolidation of memories
  and learning
         REM (dreamland)
• 10-20 min. cycles consisting of:
  – Rapid Eye Movements
  – ElectroEncepahaloGram shows fast activity
    very similar to wakeful EEG pattern
  – Suppression of peripheral muscle tone
  – Penile Tumescence
  – Often increased autonomic tone- ie,
    increased blood pressure, resp, heart rate
        REM (dreamland)
• Where dreaming occurs
• REM is marked by increased cholinergic
  activity
  – Thus REM-supression seen with anti-
    cholinergic drugs (ex. some
    antidepressants)
     Normal Sleep Pattern
• Sleep cycles between NREM and REM
  approx. 4-5 times/night
• Cycles last approx. 90min
• REM duration and frequency increase
  thru night
• Proportion of slow wave sleep (stages
  3,4) decreases thru night
   Normal Sleep Parameters
• Sleep Onset Latency- the time it takes
  one to fall asleep, averages 10-20min
• REM Latency- time between sleep
  onset and the first REM period,
  averages 90-120min
   Normal Sleep Distribution
• REM sleep accounts for approximately
  25% of total sleep time
• Non-REM sleep accounts for 75% of
  sleep time, with 25% of that spent in
  Stages 3,4 (most restful portion)
             Sleep Onset
• Mediated by increased Serotonergic
  activity in the Dorsal Raphe Nuclei of
  the Pons
  – Dampens activity in the ascending reticular
    activating system (RAS), inducing sleep
• Dopamine has opposite effect-
  promotes wakefulness
     Age-Related Changes
• Decreases in dreaming, total sleep time,
  REM, and slow-wave (deep sleep)
• Increases in early morning awakening,
  fragmentation, daytime napping, and
  phase advancement-
  – Ie, earlier to bed, and awaken earlier
“Measuring” Sleep

 Polysomnography
      The Polysomnogram
• EEG, ECG
• EOG (oculogram)
• Chin EMG
  (myelogram)
• Ant. Tibialis EMG
• Pulse Oxymeter
• Blood Pressure
Sleep Disorders
 Sleep Disorders- 2 Divisions
• Dyssomnias- disorders of quality,
  timing, or amount of sleep (quantity)
• Parasomnias- abnormal behaviors
  associated with sleep or sleep-wake
  transition, that often produce arousals
            Dyssomnias
• Primary Insomnia
• Narcolepsy
• Sleep Apnea
• Circadian Rhythm Sleep Disorder (jet
  lag, et al.)
• Restless Legs Syndrome (RLS)
• Medical/Substance related insomnia
         Primary Insomnia
• “Primary”, meaning no underlying
  medical cause
• Onset often with stressor or disruption
  to sleep schedule or environment
• Results from poor sleep hygiene, along
  with classical conditioning-
  – Faulty learning/association of sleep
    environment with state of arousal
   INSOMNIA- an epidemic?
• Definition: “Subjective” experience of
  poor sleep quality or quantity that
  adversely affects daily functioning
• Extremely common complaint in general
  practice
• 30-40% adults have occasional poor
  sleep
• 15-20% adults have chronic insomnia
    Consequences of Insomnia
•   Depression
•   Irritability
•   Decreased cognitive functioning
•   Decreased productivity
•   Injuries and accidents
             Narcolepsy
• A dyssomnia characterized by poor
  sleep quality (restless, fragmented) and
  dysfunction in the transitions between
  sleep and wakefulness
• Presents with Excessive Daytime
  Sedation (EDS)
        Narcolepsy Tetrad
• Classic tetrad of associated
  findings:
  – 1. Sleep attacks
  – 2. Cataplexy
  – 3. Sleep paralysis
  – 4. Sleep hallucinations
        1. Sleep Attacks
• Most common symptom of the tetrad
• Brief (10-20min) “power-naps”-
  refreshing and restful
• Average 10-20/wk
            2. Cataplexy
• Sudden loss of muscle tone (rarely full
  body paralysis) caused by intrusion of
  REM activity into daytime wakefulness
• Triggered by heightened emotion
• Average duration: 30 seconds
• No loss of consciousness
        3. Sleep Paralysis
• Brief paralysis upon waking
• Remain alert with full eye movements
  Can occur in the absence of Narcolepsy
  (ie, normal variant)
     4. Sleep Hallucinations
• Hypnogogic hallucinations- occur during
  transition into sleep
• Hynopompic hallucinations- occur upon
  awakening from sleep
• Can occur in the absence of Narcolepsy
  (ie, normal variant)
      Narcolepsy: Etiology
• CNS lesions: brain trauma, stroke,
  tumor, Multiple Sclerosis
• Familial/idiopathic: onset in
  adolescence or young adulthood
           Sleep Apnea
• Dyssomnia characterized by poor sleep
  quality due to frequent awakenings
  (apneas)
• Apneas last sec-minutes- produce brief
  arousal
• Presents with excessive daytime
  sedation- EDS
   Sleep Apnea: Two Types
• Obstructive Sleep Apnea: most
  common
• Central Sleep Apnea
   Obstructive Sleep Apnea
• Classic- obese, middle-aged male with
  thick neck or enlarged tonsils
• Apneas- brief gasps…silence, followed
  by loud “resuscitative” snores, and
  sometimes body movements (restless)
• Usually unaware of snoring,
  arousals…but sleep partner is aware
      Central Sleep Apnea
• Apneas- episodic cessation of central
  ventilation drive
  – Thus snoring is less common
• More in elderly, with underlying CNS
  lesions- ex. tumor, stroke
    Sleep Apnea: Consequences
•   Depression
•   Anxiety
•   Morning headaches
•   Cognitive dysfunction
•   Hypertension
   Restless Legs Syndrome
• Paresthesias and/or dysesthesias in the
  legs, relieved by movements
• Usually occur in transition from
  wakefulness to sleep
              RLS Causes
•   Peripheral neuropathies
•   Peripheral vascular disease
•   Medication side effects
•   Anemia
•   Pregnancy
•   Renal failure
Circadian Rhythm Disorders
             • Delayed Sleep
               Phase Syndrome
             • Jet Lag
             • Accelerated Sleep
               Phase Syndrome
             • Shift Work Sleep
               Disorder
       Insomnia from Medical
            Conditions
•   Reflux (GERD)
•   Nocturia
•   Peripheral neuropathies
•   Breathing problems- Asthma, COPD
•   Heart Disease/Failure
•   Pain conditions
        Psychiatric Causes of
             Insomnia
•   Depression
•   Anxiety
•   Psychosis
•   Substance intoxication/withdrawal
The End

				
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