Sleep and Sleep Histories Douglas Moul, M.D., M.P.H.
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Transcript of Sleep and Sleep Histories Douglas Moul, M.D., M.P.H.
Sleep and Sleep HistoriesDouglas Moul, M.D., M.P.H.
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“Consciousness is consciousness of an object.”
-- Jean-Paul Sartre
Death = Sleep ?
To be or not to be, that is the question-- whether it is more noble in the mind to suffer the slings and arrows of outrageous fortune, or to take arms against a sea of troubles, and by opposing, end them --
To die..., to sleep..., perchance to dream…
-- Hamlet
Modes of Sentience
• Wakefulness
• Slow Wave Sleep
• Rapid Eye-Movement Sleep
Modes of Insentience
• ComaComa
• DeathDeath
Hallucinations and Dreams
• Both often occur in the absence of a consensually validated stimulus.
• Both are experienced perceptually.
• Both can dominate awareness
• Both can be pleasant or unpleasant
• Both can at times cause overt behavior
Hallucinations vs. Dreams
• Usually during wakefulness
• Auditory > Visual• Not volitionally guided• Interferes with the stream
of thought• Usually not built from
ordinary daily events
• Usually during REM sleep• Visual > Auditory• “Lucid” Dreams can be
thematically guided• When experienced, is the
stream of thought• Often contain “day
residues.”
Myths about Sleep and Dreams
• If a person doesn’t get sleep, he or she will become psychotic.
• Everyone must get 7.5 hours of sleep.
• Psychiatrists are taught how to interpret dreams properly.
• Nightmares and hypnopompic/hypnogogic hallucinations are abnormal.
• Sleep apneas are always abnormal.
A Good Brain Anatomy Site:
http://pegasus.cc.ucf.edu/~Brainmd1/brain.html#table
Stage I Sleep: Going to Sleep
• Usually requires state of lowered autonomic arousal
• Transition from alpha to theta waves on EEG
• Is a light sleep, easily responsive to sounds
• Typically lasts from 1 to 7 minutes
• Hypnic Myoclonus may occur
Stage II Sleep: The Thalamus’ Reticular Nucleus’ Sleep Spindles
• Sleep Spindles and K complexes
• Bodily movements continue
• Lasts usually 10-25 minutes during first cycle
• Constitutes 45-55% of sleep
• Probably initiates 0.5o F temperature reduction through the Hypothalamus
Stages III-IV: Deep Sleep
• High voltage Delta waves now predominate in EEG
• High stimulus thresholds normally for arousal.
• Psychologically probably the stage that tells a person he has slept.
• Skeletal muscles still active!
REM Sleep• Usually is an arousal from Delta sleep
• Desynchrony in the EEG
• PGO waves from Pons to Thalamus to Cortex
• Theta waves in Septum and Hippocampus (related to memory/dream function?)
• Pontine reticular formation activation with skeletal muscle atonia and poikilothermia
• Lowered cardiac and pulmonary rhythms
• Periodic penile and clitoral tumescence
Wakefulness• Greater tendency to arouse from REM (REM
propensity is circadian; SWS propensity is about length-of-wakefulness)
• Septal and Hippocampal Theta waves occur during wakefulness !
• With apneas, brief awake spells can be forgotten
• Sleepiness and Fatigue can be different symptoms.
Breathing During Sleep• Sleep onset resets chemical sensitivity to PO2 and
PCO2
• In moving to new setpoints, apneas may occur, and are fairly normal
• PCO2 usually the critical setpoint for breathing during sleep
• Decreased pharyngeal tone: snoring and obstructive sleep apnea
• Greater irregularity during REM sleep
Prominent Nocturnal Hormone Patterns
• Cortisol starts out decreasing, reaches a daily minimum, then rises to a daily maximum about dawn.
• 80% of Growth Hormone can occur in the first Delta sleep period.
• Melatonin is entrained to the circadian and seasonal rhythms if not directly suppressed by bright light.
Three Physiological Factors regarding Sleep Propensity
• Previous Sleep Debt
• State of Autonomic Arousal
• Circadian Time
Effects of Sleep Deprivation
• Decreased sleep latency• Risk of microsleeps• Lowered intellectual
performance and creativity• Irritability• Decreased vigilance• Danger of switches to Mania in
Bipolar patients
• Temporarily decreased depressive mood in some depressed patients
GoodGoodNot so GoodNot so Good
Factual Pearls concerning Sleep• There is a 90-minute NonREM-REM Cycle of
sleep stages across the night
• Circadian maturity only begins to appear by 6 weeks post-partum, and may take months; Infants have a lot of REM sleep.
• Women as a group have better sleep architecture, but lower sleep quality than men.
• The elderly may not have any Delta sleep and generally have lighter sleep
Effects of Alcohol• Alcohol (affects GABA & other receptors )
induces sleep, decreases pharyngeal muscle tone encouraging obstructive sleep apneas, and initially depresses REM; later in the night REM rebounds, with possible nightmares and/or awakening.
• Sober alcoholics can expect to have poorer sleep architecture and sleep satisfaction for over a year after they have stopped drinking.
Effects of Other Layman Drugs
• Caffeine antagonizes Adenosine, a neuromodulator that decreases secretion of autonomically active chemicals (DA, NE,etc.)
• H1 Antihistamines antagonize Histamine, an activating neurochemical during wakefulness
• Nicotine is a cholinergic stimulant.
• Drugs with Anticholinergic properties may help with sleep, but impair daytime memory
Effects of Common Medications
• Benzodiazepines (e.g. Valium) (affect GABA) tend to suppress SWS
• Antidepressants and MAOIs tend to suppress REM Sleep
• Stimulants usually act on Dopamine or Norepinephrine and suppress all stages.
• Many medications hit multiple receptors, and their effects on sleep can be dose-dependent and somewhat unpredictable.