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)  min. cycles consisting of:  Rapid Eye Movements  ElectroEncepahaloGram 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

REM (dreamland)  Where dreaming occurs  REM is marked by increased brainwave 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 min

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)

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

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  3. Sleep paralysis  4. Sleep hallucinations

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

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

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)

Sleep Apnea  Dyssomnia characterized by poor sleep quality due to frequent awakenings (apneas)  Apneas last sec-minutes  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

Psychiatric Causes of Insomnia  Depression  Anxiety  Psychosis  Substance intoxication/withdrawal