sleep Flashcards Preview

BD 2 > sleep > Flashcards

Flashcards in sleep Deck (22)
Loading flashcards...

definitions of sleep

  1. the natural periodic suspension of consciousness during which the powers of the body are restored
  2. the intermediate state between wakefulness and death
  3. a reversible behavioral state of perceptual disengagement from and unresponsiveness to the environment


average hours needed for sleep

7-9 hours 


REM:NREM ratios






  • REM:NREM 50:50 
  • Enter sleep through SOREM (Sleep Onset REM Periods)


  • ~REM:NREM ~50:~50 
    • as children age, they experience more NREM
    • By 3 months, children enter sleep via NREM


  • NREM:REM ~75:~25
  • REM cycles every 90-120 minutes



NREM sleep predominates in first half of sleep and is linked to prior level of wavefulness

REM predominates in last half of sleep and is circadian linked


Homeostatic Sleep Drive model

Sleep responses are proportional to the duration of prior wakefullnes

  • Increased sleepiness
  • Increased sleep
  • Increased depth and maintenance of sleep


Circadian Rhythm model

circadian rythm model

  • Rythem generated by circadian pacemaker located in the suprachismaltic nuclei of the hypothalamus
    • common to the specific organism (each organism has its own sleep cycle i.e nochturnal)
  • Rythem is set by photic and Non-photic stimuli 

retinal blindness blocks light that drives biological clock no circadian rythem 


Systems controlled by the circadian rythem

[*] Airway function

[*] Cardiovascular activity

[*] Hematology

[*] Neoplastic cells

[*] Wake/sleep

[*] Hormonal

[*] Temperature

[*] Immune

[*] Drug metabolism

[*] Renal function


Determiniants of sleep

  • Circadian
  • Homeostatic
  • Age
  • Others
  • drugs
  • sleep disorders
    • Total sleep requirement and the timing of the wake/sleep cycle are inherent characteristics of an individual


Sleep deprevation epidemic

  • As a society, we now get 20% less sleep than our ancestors only 100 years ago.
  • College students oversleep their alarms 50% of the time.


Sleep Debt stats

 Sleep deprivation is cumulative.

  • A person does not come to require less sleep or get used to being sleep-deprived.
  • sleep deprevation creates sleep debt that must be resotred inorder to feel refreshed 
    • The payback requirement is less than the debt at a ratio of about 2.5h of debt to 1h sleep. 


Social cost of sleep debt

  •  Major industrial disasters e.g. Chernobyl, Three Mile Island, and Bhopal, and serious accidents, e.g Exxon Valdez and Challenger, have been officially attributed to errors in judgment caused by lack of sleep.
  • Car crashes, in the US, due to falling asleep at the wheel exceed 100,000/year and result in 1,500 deaths



Polysomnography: Scoring and Staging




Polysomnography: Scoring and Staging

  • overnight sleep study
  • measures:  EEG, EOG, EMG, Leg EMG, Airflow, Respiratory Effort, ECG



Stages of sleep

Stage W (Wakefulness)


  • Stage N1 (NREM 1)
  • Stage N2 (NREM 2)
  • Stage N3 (NREM 3)

Stage R (REM)


Multiple Sleep Latency Test

Five 20-minute nap opportunities are given at two-hour intervals. 

Parameters measured are:

  • average latency to sleep onset
  • appearance of REM sleep

Norms for sleep latency(time to fall asleep):

  • 0-5 minutes indicative of severe hypersomnia
  • <5 and >10 borderline
  • 10 to 20 normal
    • 2 or more naps with REM periods: abnormal
      • ​indicates narcolepsy


Maintenance of Wakefulness Test

  • Designed to test the patent’s ability to stay awake
  • The patient is seated upright in bed in a dimly lighted room and asked to stay awake for 40 minutes
  • Test is repeated 4 times throughout the day



 Used to track activity and determine if asleep or not asleep 

  • pt wears a device on wrist that has an accelerometer and measures movement to detect sleep


Psychophysiological Insomnia


  • Meets Criteria for insomnia
  • Present for at least one month
  • Evidence of conditioned sleep difficulty and/or heightened arousal in bed



  • Cognitive Behavioral Therapies
  • Stimulus Control
  • Sleep Restriction
  • Medications


Obstructive Sleep Apnea

Symptoms & Signs

  • Loud snoring, observed apneas, daytime sleepiness
  • Morning sore throat or headache
  • Elevated BMI, crowded oropharynx, hypertension


  • •Polysomnography is the gold standard

​Tx - surgery, devices to support airway 


Restless leg syndrome


U--Unpleasant limb sensations with urge to move

 R--Symptoms precipitated by rest

 G-Better with movement (getting up)

 E--Symptoms worse in the evening or at night

treatment - medication



Characterized by sleepiness and symptoms due to the abnormal regulation of REM sleep

Symptom Prevalence

  • Excessive Daytime Sleepiness  100%
  • Cataplexy  70%
  • Hypnagogic Hallucinations  66%
  • Sleep Paralysis  60%
    • ​typically diagnosed in adolecense 

Secondary narcolepsy can occur in patients with head trauma, stroke, MS, brain tumors, CNS infections


Circadian Rhythm Sleep Disorders  

  • Delayed Sleep Phase Type
  • Advanced Sleep Phase Type
  • Irregular Sleep-Wake Type
  • Non-entrained type(Free Running)
  • Jet Lag Type
  • Shift Work Type
  • Due to Medical Condition, Substance, Alcohol or other



Disorders that intrude into the sleep process and are not primarily disorders of sleep and wake state

  • Parasomnias are undesirable physical events or experiences that arise from sleep or sleep - wake transition
  • Encompass movements, behaviors, emotions, perceptions, and dreaming
    • Sleepwalking (wide range of behaviors—getting dressed, leaving house, driving)

    • Sleep Terrors

    • Sleep-Related Eating Disorder (eating in sleep)