The 4 Stages of Sleep: Understanding REM and Non-REM Sleep

2. 2 Phases: REM and Non-REM Sleep

3. 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

4. Stage One Brief transition between wakefulness and sleep (accounts for only 5% of sleep time)

5. Stage Two Light sleep Accounts for 50% of total sleep time ElectroEncephaloGram (EEG) shows some characteristic findings

6. EEG in Stage 2

7. 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

8. 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

9. REM (dreamland) 10-20 min. cycles consisting of: Rapid Eye Movements E lectro E ncepahalo G ram shows fast activity very similar to wakeful EEG pattern Suppression of peripheral muscle tone Often increased autonomic tone- ie, increased blood pressure, resp, heart rate

10. REM (dreamland) Where dreaming occurs REM is marked by increased brainwave activity Thus REM-supression seen with anti-cholinergic drugs (ex. some antidepressants)

11. 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

12. 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

13. 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)

14. 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

16. 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

17. Dyssomnias Primary Insomnia Narcolepsy Sleep Apnea Circadian Rhythm Sleep Disorder (jet lag, et al.) Restless Legs Syndrome (RLS) Medical/Substance related insomnia

18. 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

19. 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

20. Consequences of Insomnia Depression Irritability Decreased cognitive functioning Decreased productivity Injuries and accidents

21. 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)

22. Narcolepsy Tetrad Classic tetrad of associated findings: 1. Sleep attacks 3. Sleep paralysis 4. Sleep hallucinations

23. 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

24. Sleep Paralysis Brief paralysis upon waking Remain alert with full eye movements Can occur in the absence of Narcolepsy (ie, normal variant)

25. 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)

26. Sleep Apnea Dyssomnia characterized by poor sleep quality due to frequent awakenings (apneas) Apneas last sec-minutes Presents with excessive daytime sedation- EDS

27. Sleep Apnea: Two Types Obstructive Sleep Apnea: most common Central Sleep Apnea

28. Obstructive Sleep Apnea Classic- obese, middle-aged male with thick neck or enlarged tonsils Apneas- brief gaspssilence, followed by loud resuscitative snores, and sometimes body movements (restless) Usually unaware of snoring, arousalsbut sleep partner is aware

29. 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

30. Sleep Apnea: Consequences Depression Anxiety Morning headaches Cognitive dysfunction Hypertension

31. Restless Legs Syndrome Paresthesias and/or dysesthesias in the legs, relieved by movements Usually occur in transition from wakefulness to sleep

32. RLS Causes Peripheral neuropathies Peripheral vascular disease Medication side effects Anemia Pregnancy Renal failure

33. Circadian Rhythm Disorders Delayed Sleep Phase Syndrome Jet Lag Accelerated Sleep Phase Syndrome Shift Work Sleep Disorder

34. Psychiatric Causes of Insomnia Depression Anxiety Psychosis Substance intoxication/withdrawal