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 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 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)

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